Microsoft Version Numbering

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Software Versioning


Software versioning is the process of assigning either unique version names or unique version numbers to unique states of computer software. Within a given version number category (major, minor), these numbers are generally assigned in increasing order and correspond to new developments in the software. At a fine-grained level, revision control is often used for keeping track of incrementally different versions of information, whether or not this information is computer software.

Modern computer software is often tracked using two different software versioning schemes—internal version number that may be incremented many times in a single day, such as a revision control number, and a released version that typically changes far less often, such as semantic versioning or a project code name.

1 Schemes
1.1 Sequence-based identifiers
1.1.1 Change significance
1.1.2 Degree of compatibility
1.1.3 Designating development stage
1.1.4 Incrementing sequences
1.1.5 Separating sequences
1.1.6 Number of sequences
1.1.7 Using negative numbers
1.2 Date of release
1.3 Alphanumeric codes
1.4 TeX
1.5 Apple
1.6 Other schemes
2 Internal version numbers
3 Pre-release versions
4 Modifications to the numeric system
4.1 Odd-numbered versions for development releases
4.2 Apple
5 Political and cultural significance of version numbers
5.1 Version 1.0 as a milestone
5.2 To describe program history
5.3 Matching competitor’s numbers
5.4 Apple
6 Dropping the most significant element
6.1 Superstition
6.2 Geek culture
7 Overcoming perceived marketing difficulties
8 Significance in software engineering
9 Significance in technical support
10 Version numbers for files and documents
11 Version number ordering systems
12 Use in other media


A variety of version numbering schemes have been created to keep track of different versions of a piece of software. The ubiquity of computers has also led to these schemes being used in contexts outside computing.

Sequence-based Identifiers

In sequence-based software versioning schemes, each software release is assigned a unique identifier that consists of one or more sequences of numbers or letters. This is the extent of the commonality; however, schemes vary widely in areas such as the quantity of sequences, the attribution of meaning to individual sequences, and the means of incrementing the sequences.

Change Significance

In some schemes, sequence-based identifiers are used to convey the significance of changes between releases: changes are classified by significance level, and the decision of which sequence to change between releases is based on the significance of the changes from the previous release, whereby the first sequence is changed for the most significant changes, and changes to sequences after the first represent changes of decreasing significance.

For instance, in a scheme that uses a four-sequence identifier, the first sequence may be incremented only when the code is completely rewritten, while a change to the user interface or the documentation may only warrant a change to the fourth sequence.

This practice permits users (or potential adopters) to evaluate how much real-world testing a given software release has undergone. If changes are made between, say, 1.3rc4 (a release candidate) and the production release of 1.3, then that release, which asserts that it has had a production-grade level of testing in the real world, in fact contains changes which have not necessarily been tested in the real world at all. This approach commonly permits the third level of numbering (“change”), but does not apply this level of rigor to changes in that number: 1.3.1, 1.3.2, 1.3.3, 1.3.4… 1.4.1, etc.

In principle, in subsequent releases, the major number is increased when there are significant jumps in functionality such as changing the framework which could cause incompatibility with interfacing systems, the minor number is incremented when only minor features or significant fixes have been added, and the revision number is incremented when minor bugs are fixed. A typical product might use the numbers 0.9 (for beta software), 0.9.1, 0.9.2, 0.9.3, 1.0, 1.0.1, 1.0.2, 1.1, 1.1.1, 2.0, 2.0.1, 2.0.2, 2.1, 2.1.1, 2.1.2, 2.2, etc. Developers may choose to jump multiple minor versions at a time to indicate significant features have been added, but are not enough to warrant incrementing a major version number; for example Internet Explorer 5 from 5.1 to 5.5, or Adobe Photoshop 5 to 5.5. This may be done to emphasize the value of the upgrade to the software user, or, as in Adobe’s case, to represent a release halfway between major versions (although levels of sequence based versioning are not limited to a single digit, as in Drupal version 7.12).

A different approach is to use the major and minor numbers, along with an alphanumeric string denoting the release type, e.g. “alpha”, “beta” or “release candidate”. A software release train using this approach might look like 0.5, 0.6, 0.7, 0.8, 0.9 == 1.0b1, 1.0b2 (with some fixes), 1.0b3 (with more fixes) == 1.0rc1 (which, if it is stable enough) == 1.0. If 1.0rc1 turns out to have bugs which must be fixed, it turns into 1.0rc2, and so on. The important characteristic of this approach is that the first version of a given level (beta, RC, production) must be identical to the last version of the release below it: you cannot make any changes at all from the last beta to the first RC, or from the last RC to production. If you do, you must roll out another release at that lower level.[dubious – discuss]

However, since version numbers are human-generated, not computer-generated, there is nothing that prevents arbitrary changes that violate such guidelines: for example, the first sequence could be incremented between versions that differ by not even a single line of code, to give the (false) impression that very significant changes were made.

Other schemes impart meaning on individual sequences:




Again, in these examples, the definition of what constitutes a “major” as opposed to a “minor” change is entirely subjective and up to the author, as is what defines a “build”, or how a “revision” differs from a “minor” change.

Shared libraries in Solaris and Linux may use the current.revision.age format where

current: The most recent interface number that the library implements.
revision: The implementation number of the current interface.
age: The difference between the newest and oldest interfaces that the library implements.
A similar problem of relative change significance and versioning nomenclature exists in book publishing, where edition numbers or names can be chosen based on varying criteria.

In most proprietary software, the first released version of a software product has version 1.

Degree of Compatibility

Some projects use the major version number to indicate incompatible releases. Two examples are Apache APR and the FarCry CMS.

Semantic Versioning is a formal convention for specifying compatibility using a three-part version number: major version; minor version; and patch. The patch number is incremented for minor changes and bug fixes which do not change the software’s application programming interface (API). The minor version is incremented for releases which add new, but backward-compatible, API features, and the major version is incremented for API changes which are not backward-compatible. For example, software which relies on version 2.1.5 of an API is compatible with version 2.2.3, but not necessarily with 3.2.4.

Often programmers write new software to be backward compatible, i.e., the new software is designed to interact correctly with older versions of the software (using old protocols and file formats) and the most recent version (using the latest protocols and file formats). For example, IBM z/OS is designed to work properly with 3 consecutive major versions of the operating system running in the same sysplex. This enables people who run a high availability computer cluster to keep most of the computers up and running while one machine at a time is shut down, upgraded, and restored to service.

Often packet headers and file format include a version number – sometimes the same as the version number of the software that wrote it; other times a “protocol version number” independent of the software version number. The code to handle old deprecated protocols and file formats is often seen as cruft.

Designating development stage
Some schemes use a zero in the first sequence to designate alpha or beta status for releases that are not stable enough for general or practical deployment and are intended for testing or internal use only.

It can be used in the third position:

  • 0 for alpha (status)
  • 1 for beta (status)
  • 2 for release candidate
  • 3 for (final) release

For instance:

  • instead of 1.2-a1
  • instead of 1.2-b2 (beta with some bug fixes)
  • instead of 1.2-rc3 (release candidate)
  • instead of 1.2-r (commercial distribution)
  • instead of 1.2-r5 (commercial distribution with many bug fixes)

Incrementing Sequences

There are two schools of thought regarding how numeric version numbers are incremented. Most free and open-source software packages, including MediaWiki, treat versions as a series of individual numbers, separated by periods, with a progression such as 1.7.0, 1.8.0, 1.8.1, 1.9.0, 1.10.0, 1.11.0, 1.11.1, 1.11.2, and so on. On the other hand, some software packages identify releases by decimal numbers: 1.7, 1.8, 1.81, 1.82, 1.9, etc. Decimal versions were common in the 1980s, for example with NetWare, DOS, and Microsoft Windows, but even in the 2000s have been for example used by Opera and Movable Type. In the decimal scheme, 1.81 is the minor version following 1.8, while maintenance releases (i.e. bug fixes only) may be denoted with an alphabetic suffix, such as 1.81a or 1.81b.

The standard GNU version numbering scheme is major.minor.revision, but emacs is a notable example using another scheme where the major number (1) was dropped and a user site revision was added which is always zero in original emacs packages but increased by distributors. Similarly, Debian package numbers are prefixed with an optional “epoch”, which is used to allow the versioning scheme to be changed.

Separating Sequences

When printed, the sequences may be separated with characters. The choice of characters and their usage varies by scheme. The following list shows hypothetical examples of separation schemes for the same release (the thirteenth third-level revision to the fourth second-level revision to the second first-level revision):

  • A scheme may use the same character between all sequences: 2.4.13, 2/4/13, 2-4-13
  • A scheme choice of which sequences to separate may be inconsistent, separating some sequences but not others: 2.413
  • A scheme’s choice of characters may be inconsistent within the same identifier: 2.4_13

When a period is used to separate sequences, it may or may not represent a decimal point, — see “Incrementing sequences” section for various interpretation styles.

Number of Sequences

There is sometimes a fourth, unpublished number which denotes the software build (as used by Microsoft). Adobe Flash is a notable case where a four-part version number is indicated publicly, as in Some companies also include the build date. Version numbers may also include letters and other characters, such as Lotus 1-2-3 Release 1a.

Using Negative Numbers

Some projects use negative version numbers. One example is the SmartEiffel compiler which started from -1.0 and counted upwards to 0.0.

Date of Release

The Wine project formerly used a date versioning scheme, which uses the year followed by the month followed by the day of the release; for example, “Wine 20040505”. Ubuntu Linux uses a similar versioning scheme—Ubuntu 11.10, for example, was released October 2011. Some video games also use date as versioning, for example the arcade game Street Fighter EX. At startup it displays the version number as a date plus a region code, for example 961219 ASIA.

When using dates in versioning, for instance, file names, it is common to use the ISO 8601 scheme: YYYY-MM-DD, as this is easily string sorted to increasing/decreasing order. The hyphens are sometimes omitted.

Microsoft Office build numbers are an encoded date: the first two numbers is the number of months passed from the January of the year the project started (with each major Office release being a different project), and the last two numbers are the day of that month. So 3419 is the 19th day of the 34th month after the month of January of the year the project started.

Other examples that identify versions by year include Adobe Illustrator 88 and WordPerfect Office 2003. When a date is used to denote version, it is generally for marketing purposes, and an actual version number also exists. For example, Microsoft Windows 95 is internally versioned as MS-DOS 7.00 and Windows 4.00, Microsoft Windows 2000 Server is internally versioned as Windows NT 5.0 (“NT” being a reference to the original product name).

Alphanumeric codes


Macromedia Flash MX


TeX has an idiosyncratic version numbering system. Since version 3, updates have been indicated by adding an extra digit at the end, so that the version number asymptotically approaches π; this is a form of unary numbering – the version number is the number of digits. The current version is 3.14159265. This is a reflection of the fact that TeX is now very stable, and only minor updates are anticipated. TeX developer Donald Knuth has stated that the “absolutely final change (to be made after my death)” will be to change the version number to π, at which point all remaining bugs will become permanent features.

In a similar way, the version number of METAFONT asymptotically approaches e.


Apple has a formalised version number structure based around the NumVersion struct, which specifies a one- or two-digit major version, a one-digit minor version, a one-digit “bug” (i.e. revision) version, a stage indicator (drawn from the set development/prealpha, alpha, beta and final/release), and a one-byte (i.e. having values in the range 0–255) pre-release version, which is only used at stages prior to final. In writing these version numbers as strings, the convention is to omit any parts after the minor version whose value are zero (with “final” being considered the zero stage), thus writing 1.0.2 (rather than 1.0.2b12), 1.0.2 (rather than 1.0.2f0), and 1.1 (rather than 1.1.0f0).

Other Schemes

Some software producers use different schemes to denote releases of their software. For example, the Microsoft Windows operating system was first labelled with standard version numbers for Windows 1.0 through Windows 3.11. After this Microsoft excluded the version number from the product name. For Windows 95 (version 4.0), Windows 98 (4.10) and Windows 2000 (5.0), year of the release was included in the product title. After Windows 2000, Microsoft created the Windows Server family which continued the year-based style with a difference: For minor releases, Microsoft suffixed “R2” to the title, e.g., Windows Server 2008 R2. This style had remained consistent to this date. The client versions of Windows however did not adopt a consistent style. First, they received names with arbitrary alphanumeric suffixes as with Windows ME (4.90), Windows XP (5.1) and Windows Vista (6.0). Then, once again Microsoft adopted incremental numbers in the title, but this time, they were not version numbers; the version numbers of Windows 7, Windows 8 and Windows 8.1 are respectively 6.1, 6.2 and 6.3. In Windows 10, the version number leaped to 10.0.

The Debian project uses a major/minor versioning scheme for releases of its operating system, but uses code names from the movie Toy Story during development to refer to stable, unstable and testing releases.

BLAG Linux and GNU features very large version numbers: major releases have numbers such as 50000 and 60000, while minor releases increase the number by 1 (e.g. 50001, 50002). Alpha and beta releases are given decimal version numbers slightly less than the major release number, such as 19999.00071 for alpha 1 of version 20000, and 29999.50000 for beta 2 of version 30000. Starting at 9001 in 2003, the most recent version as of 2011 is 140000.

Internal Version Numbers

Software may have an “internal” version number which differs from the version number shown in the product name (and which typically follows version numbering rules more consistently). Java SE 5.0, for example, has the internal version number of 1.5.0, and versions of Windows from NT 4 on have continued the standard numerical versions internally: Windows 2000 is NT 5.0, XP is Windows NT 5.1, Windows Server 2003 and Windows XP Professional x64 Edition are NT 5.2, Windows Server 2008 and Vista are NT 6.0, Windows Server 2008 R2 and Windows 7 are NT 6.1, Windows Server 2012 and Windows 8 are NT 6.2, and Windows Server 2012 R2 and Windows 8.1 are NT 6.3. Note, however, that Windows NT is only on its fourth major revision, as its first release was numbered 3.1 (to match the then-current Windows release number).

Pre-release Versions

In conjunction with the various versioning schemes listed above, a system for denoting pre-release versions is generally used, as the program makes its way through the stages of the software release life cycle.

Programs that are in an early stage are often called “alpha” software, after the first letter in the Greek alphabet. After they mature but are not yet ready for release, they may be called “beta” software, after the second letter in the Greek alphabet. Generally alpha software is tested by developers only, while beta software is distributed for community testing.

Some systems use numerical versions less than 1 (such as 0.9), to suggest their approach toward a final “1.0” release. This is a common convention in open source software. However, if the pre-release version is for an existing software package (e.g. version 2.5), then an “a” or “alpha” may be appended to the version number. So the alpha version of the 2.5 release might be identified as 2.5a or 2.5.a.

An alternative is to refer to pre-release versions as “release candidates”, so that software packages which are soon to be released as a particular version may carry that version tag followed by “rc-#”, indicating the number of the release candidate – and when the final version is released, the “rc” tag is removed.

Modifications to the Numeric System

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Various modifications have been introduced to distinguish versions or sets of versions. A set of releases or versions having the same major or minor version number may be collectively referred to as .x, for example version 2.2.x to refer to versions 2.2, 2.2.1, 2.2.2, and all other versions in the 2.2 branch of that software.

Odd-numbered versions for development releases

Between the 1.0 and the 2.6.x series, the Linux kernel used odd minor version numbers to denote development releases and even minor version numbers to denote stable releases; see Linux kernel: Version numbering. For example, Linux 2.3 was a development family of the second major design of the Linux kernel, and Linux 2.4 was the stable release family that Linux 2.3 matured into. After the minor version number in the Linux kernel is the release number, in ascending order; for example, Linux 2.4.0 → Linux 2.4.22. Since the 2004 release of the 2.6 kernel, Linux no longer uses this system, and has a much shorter release cycle.

The same odd-even system is used by some other software with long release cycles, such as GNOME.


Apple had their own twist on this habit during the era of the classic Mac OS: although there were minor releases, they rarely went beyond 1, and when they did, they twice jumped straight to 5, suggesting a change of magnitude intermediate between a major and minor release (thus, 8.5 really means ‘eight and a half’, and 8.6 is ‘eight and a half point one’). The complete sequence of versions (neglecting revision releases) is 1.0, 1.1, 2.0, 2.1, 3.0, 3.2 (skipping 3.1), 4.0, 4.1, 5.0, 5.1, 6.0, 7.0, 7.1, 7.5, 7.6, 8.0, 8.1, 8.5, 8.6, 9.0, 9.1, 9.2.

Mac OS X (since renamed macOS) departed from this trend, in large part because “X” (the Roman numeral for 10) is in the name of the product. As a result, all versions of OS X begin with the number 10. The first major release of OS X was given the version number 10.0, but the next major release was not 11.0. Instead, it was named version 10.1, followed by 10.2, 10.3, and so on for each subsequent major release.

In this system, the third number (instead of the second) denotes a minor release, and a fourth number (instead of the third) denotes bug-fix/revision releases. Because the first number is always 10, and because the subsequent numbers are not decimal, but integer values, the 11th major version of OS X is labeled “10.10” rather than “11.0”.

Political and Cultural Significance of Version Numbers

Version 1.0 as a Milestone

Proprietary software developers often start at version 1 for the first release of a program and increment the major version number with each significant update.

In contrast to this, the free-software community tends to use version 1.0 as a major milestone, indicating that the software is “complete”, that it has all major features, and is considered reliable enough for general release.

In this scheme, the version number slowly approaches 1.0 as more and more bugs are fixed in preparation for the 1.0 release. The developers of MAME do not intend to release a version 1.0 of their emulator program. The argument is that it will never be truly “finished” because there will always be more arcade games. Version 0.99 was simply followed by version 0.100 (minor version 100 > 99). In a similar fashion Xfire 1.99 was followed by 1.100. After 8 years of development, eMule reached version 0.50a.

To describe Program History

Winamp released an entirely different architecture for version 3 of the program. Due to lack of backward compatibility with plugins and other resources from the major version 2, a new version was issued that was compatible with both version 2 and 3. The new version was set to 5 (2+3), skipping version 4. A similar situation occurred with UnixWare 7, which was the combination of UnixWare 2 and OpenServer 5.

Matching Competitor’s Numbers

A practice in the software industry is to make major jumps in numeric major or minor version numbers for reasons which do not seem (to many members of the program’s audience) to merit the marketing version numbers.

This can be seen in many examples of product version numbering by Microsoft, America Online, Sun Solaris, Java Virtual Machine, SCO Unix, WordPerfect, the filePro DB/RAD programming package, which went from 2.0 to 3.0 to 4.0 to 4.1 to 4.5 to 4.8 to 5.0, and is about to go to 5.6, with no intervening release. A slightly different version can be seen in AOL’s PC client software, which tends to have only major releases (5.0, 6.0, 7.0, etc.). Likewise, Microsoft Access jumped from version 2.0 to version 7.0, to match the version number of Microsoft Word.

Microsoft has also been the target of ‘catch-up’ versioning, with the Netscape browsers skipping version 5 to 6, in line with Microsoft’s Internet Explorer, but also because the Mozilla application suite inherited version 5 in its user agent string during pre-1.0 development and Netscape 6.x was built upon Mozilla’s code base.

Another example of keeping up with competitors is when Slackware Linux jumped from version 4 to version 7 in 1999.


Apple has a particular form of version number skipping, in that it has leveraged its use of the Roman numeral X in its marketing across multiple product lines. Both Quicktime and Final Cut Pro jumped from versions 7 directly to version 10. Like with Mac OS X, the products were not upgrades to previous versions, but brand new programs, branded as Quicktime X and Final Cut Pro X, but unlike Apple’s desktop operating systems, there were no major versions 8 or 9. As with OS X, however, minor releases are denoted using a third digit, rather than a second digit. Consequently, major releases for these programs also employ the second digit, as Apple does with OS X. In WWDC 2016, they announced that Mac OS X will now onwards be called macOS.

Dropping the most Significant Element

Sun’s Java has at times had a hybrid system, where the internal version number has always been 1.x but has been marketed by reference only to the x:

  • JDK 1.0.3
  • JDK 1.1.2 through 1.1.8
  • J2SE 1.2.0 (“Java 2”) through 1.4.2
  • Java 1.5.0, 1.6.0, 1.7.0, 1.8.0 (“Java 5, 6, 7, 8”)

Sun also dropped the first digit for Solaris, where Solaris 2.8 (or 2.9) is referred to as Solaris 8 (or 9) in marketing materials.

A similar jump took place with the Asterisk open-source PBX construction kit in the early 2010s, whose project leads announced that the current version 1.8.x would soon be followed by version 10.

This approach, panned by many because it breaks the semantic significance of the sections of the version number, has been adopted by an increasing number of vendors including Mozilla (for Firefox).


  • The Office 2007 release of Microsoft Office has an internal version number of 12. The next version Office 2010 has an internal version of 14, due to superstitions surrounding the number 13.
  • Roxio Toast went from version 12 to version 14, likely in an effort to skip the superstitions surrounding the number 13.
  • Corel’s WordPerfect Office, version 13 is marketed as “X3” (Roman number 10 and “3”). The procedure has continued into the next version, X4. The same has happened with Corel’s Graphic Suite (i.e. CorelDRAW, Corel Photo-Paint) as well as its video editing software “Video Studio”.
  • Sybase skipped major versions 13 and 14 in its Adaptive Server Enterprise relational database product, moving from 12.5 to 15.0.
    ABBYY Lingvo Dictionary uses numbering 12, x3 (14), x5 (15).

Geek Culture

  • The SUSE Linux distribution started at version 4.2, to reference 42, “the answer to the ultimate question of life, the universe and everything” mentioned in Douglas Adams’ The Hitchhiker’s Guide To The Galaxy.
  • A Slackware Linux distribution was versioned 13.37, referencing leet.
  • Finnix skipped from version 93.0 to 100, partly to fulfill the assertion, “There Will Be No Finnix ’95”, a reference to Windows 95.
  • The Tagged Image File Format specification has used 42 as internal version number since its inception, its designers not expecting to alter it anymore during their (or its) lifetime since it would conflict with its development directives.

Overcoming perceived Marketing Difficulties

In the mid-1990s, the rapidly growing CMMS, Maximo, moved from Maximo Series 3 directly to Series 5, skipping Series 4 due to that number’s perceived marketing difficulties in the Chinese market, where the number 4 is associated with “death” (see tetraphobia). This did not, however, stop Maximo Series 5 version 4.0 being released. (It should be noted the “Series” versioning has since been dropped, effectively resetting version numbers after Series 5 version 1.0’s release.)

Significance in Software Engineering

Version numbers are used in practical terms by the consumer, or client, to identify or compare their copy of the software product against another copy, such as the newest version released by the developer. For the programmer or company, versioning is often used on a revision-by-revision basis, where individual parts of the software are compared and contrasted with newer or older revisions of those same parts, often in a collaborative version control system.

In the 21st century, more programmers started to use a formalised version policy, such as the Semantic Versioning policy. The purpose of such policies is to make it easier for other programmers to know when code changes are likely to break things they have written. Such policies are especially important for software libraries and frameworks, but may also be very useful to follow for command-line applications (which may be called from other applications) and indeed any other applications (which may be scripted and/or extended by third parties).

Versioning is also a required practice to enable many schemes of patching and upgrading software, especially to automatically decide what and where to upgrade to.

Significance in Technical Support

Version numbers allow people providing support to ascertain exactly which code a user is running, so that they can rule out bugs that have already been fixed as a cause of an issue, and the like. This is especially important when a program has a substantial user community, especially when that community is large enough that the people providing technical support are not the people who wrote the code. The semantic meaning of version.revision.change style numbering is also important to information technology staff, who often use it to determine how much attention and research they need to pay to a new release before deploying it in their facility. As a rule of thumb, the bigger the changes, the larger the chances that something might break (although examining the Changelog, if any, may reveal only superficial or irrelevant changes). This is one reason for some of the distaste expressed in the “drop the major release” approach taken by Asterisk et alia: now, staff must (or at least should) do a full regression test for every update.

Version Numbers for Files and Documents

Some computer file systems, such as the OpenVMS Filesystem, also keep versions for files.

Versioning amongst documents is relatively similar to the routine used with computers and software engineering, where with each small change in the structure, contents, or conditions, the version number is incremented by 1, or a smaller or larger value, again depending on the personal preference of the author and the size or importance of changes made.

Version Number Ordering Systems

Version numbers very quickly evolve from simple integers (1, 2, …) to rational numbers (2.08, 2.09, 2.10) and then to non-numeric “numbers” such as 4:3.4.3-2. These complex version numbers are therefore better treated as character strings. Operating systems that include package management facilities (such as all non-trivial Linux or BSD distributions) will use a distribution-specific algorithm for comparing version numbers of different software packages. For example, the ordering algorithms of Red Hat and derived distributions differ to those of the Debian-like distributions.

As an example of surprising version number ordering implementation behavior, in Debian, leading zeroes are ignored in chunks, so that 5.0005 and 5.5 are considered as equal, and 5.5<5.0006. This can confuse users; string-matching tools may fail to find a given version number; and this can cause subtle bugs in package management if the programmers use string-indexed data structures such as version-number indexed hash tables.

In order to ease sorting, some software packages will represent each component of the major.minor.release scheme with a fixed width. Perl represents its version numbers as a floating-point number, for example, Perl’s 5.8.7 release can also be represented as 5.008007. This allows a theoretical version of 5.8.10 to be represented as 5.008010. Other software packages will pack each segment into a fixed bit width, for example, on Windows, version number 6.3.9600.16384 would be represented as hexadecimal 0x0006000325804000. The floating-point scheme will break down if any segment of the version number exceeds 999; a packed-binary scheme employing 16 bits apiece after 65535.

Use in Other Media

Software-style version numbers can be found in other media.

In some cases, the use is a direct analogy (for example: Jackass 2.5, a version of Jackass Number Two with additional special features; the second album by Garbage, titled Version 2.0; or Dungeons & Dragons 3.5, where the rules were revised from the third edition, but not so much as to be considered the fourth).

More often it’s used to play on an association with high technology, and doesn’t literally indicate a ‘version’ (e.g., Tron 2.0, a video game followup to the film Tron, or the television series The IT Crowd, which refers to the second season as Version 2.0). A particularly notable usage is Web 2.0, referring to websites from the early 2000s that emphasized user-generated content, usability and interoperability.

Brief History of Microsoft Windows

Don’t be surprised if I say that 9 out of 10 computers run some version of the Windows operating system, today. However, no one could have predicted this outcome when the whole journey started with MS-DOS and a vision to have every computer on a desktop. Below, you will find a chronology of events that take you through highlights from the first 25 years of Windows, more preferably – A History of Windows.


History of Windows

In 1975, Gates and Allen formed a partnership called Microsoft. Like most start-ups, Microsoft began small, but had a huge vision—a computer on every desktop and in every home. During the next years, Microsoft began to change the ways we work.

In June 1980, Gates and Allen hired Gates’ former Harvard classmate Steve Ballmer to help run the company.

IBM approached Microsoft about a project code-named “Chess.” In response, Microsoft focused on a new operating system—the software that manages, or runs, the computer hardware and also serves to bridge the gap between the computer hardware and programs, such as a word processor. It’s the foundation on which computer programs can run. They named their new operating system “MS-DOS.”

When the IBM PC running MS-DOS shipped in 1981, it introduced a whole new language to the general public.

Microsoft worked on the first version of a new operating system. Interface Manager was the code name and was considered as the final name, but Windows prevailed because it best described the boxes or computing “windows” that were fundamental to the new system. Windows was announced in 1983, but it took a while to develop. Skeptics called it “vaporware.”

On November 20, 1985, two years after the initial announcement, Microsoft shipped Windows 1.0.

History of Windows


Windows 1.0 required a minimum of 256 kilobytes (KB), two double-sided floppy disk drives, and a graphics adapter card. A hard disk and 512 KB memory was recommended for running multiple programs or when using DOS 3.0 or higher. It was originally developed by Microsoft for IBM-compatible personal computers. Although the first version of OS from Microsoft, MS-DOS was little-used or preferred alternative to Apple’s Macintosh. Despite witnessing little success, Microsoft continued to offer support for MS-DOS till the development of Windows XP.



Q: Ever wondered, what MS-DOS stood for?

Microsoft Disk Operating System

Windows 1.0 – 2.0 (1985-1992)

Instead of typing MS-DOS commands, Windows 1.0 allowed users to point and click to access the windows.

In 1987 Microsoft released Windows 2.0, which was designed for the designed for the Intel 286 processor. This version added desktop icons, keyboard shortcuts and improved graphics support.

Q: Why was Windows OS named so?

Microsoft Windows 1.0 was named so since the computing boxes, or Windows design represented a fundamental aspect of the operating system.

Windows 3.0 – 3.1 (1990–1994)

Microsoft released Windows 3.0 in May, 1900 offering better icons, performance and advanced graphics with 16 colors designed for Intel 386 processors. Its popularity grew by manifolds following the release of SDK that helped software developers focus more on writing and less on writing device drivers. With Windows 3.0 Microsoft completely rewrote the application development environment. The OS included Program Manager, File Manager and Print Manager and games, remember Solitare, a complete time waster??

Q: What does SDK stands for?

SDK refers to a set of tools that allows for the creation of applications for certain software.

Windows 95 (August 1995)

A major release of the Microsoft Windows operating system that caused Apple’s Market share to decline or shrink was Windows 95. Windows 95 as the name suggests was released in 1995 represented a significant advance over its precursor, Windows 3.1. By the way, this was also the time when the first version of Microsoft’s proprietary browser – Internet Explorer 1 was rolled out in August 1995 to catch up the Internet wave.


Windows 95

Windows 98 (June 1998)

Described as an operating system that “Works Better & Plays Better, ‘Windows 98’ offered support for a number of new technologies, including FAT32, AGP, MMX, USB, DVD, and ACPI. Also, it was the first OS to include a tool called Windows Update. The tool alerted the customers when software updates became available for their computers.

Q: Which was the last version based on MS-DOS application?

Windows 98 indeed, was the last version based on MS?DOS.

Windows ME – Millennium Edition (September 2000)

The Windows Millennium Edition, referrd as “Windows Me” was an update to the Windows 98 core that included some features of the Windows 2000 operating system. The version had the “boot in DOS” option removed but included other enhancements like Windows Media player and Movie Maker for basic video editing.

Q: System Restore, a feature that rolled your PC software configuration back to to a date or time before a problem occurred first appeared in which version of Windows?

Windows ME – Millennium Edition

Windows NT 3.1 – 4.0 (1993-1996)

A version of the Windows OS with 32-bit supported for preemptive multitasking. Two versions of Windows NT:

  1. Windows NT Server – Designed to act as a server in networks
  2. Windows NT – Workstation for stand-alone or client workstations

Windows 2000 (February 2000)

W2K (abbreviated form) was an operating system for business desktop and laptop systems to run software applications, connect to Internet and intranet sites, and access files, printers, and network resources. Windows 2000 4 versions released by Microsoft

  1. Professional (for business desktop and laptop systems)
  2. Server (both a Web server and an office server)
  3. Advanced Server (for line-of-business applications)
  4. Datacenter Server (for high-traffic computer networks)

Windows XP (October 2001)

This version of the OS was built on Windows 2000 Kernel and was introduced in 2001 along with a redesigned look and feel. It was made available to public in 2 versions

  1. Windows Xp Home
  2. Windows XP Professional

Microsoft focused on mobility for both editions, including plug and play features for connecting to wireless networks was introduced in this version of Windows and it proved to one of Microsoft’s best-selling products. Its use started declining with more Windows 7 deployments.


Windows XP

Windows Vista (November 2006)

A marketing flop! People expected too much from its WOW factor. Windows Vista released in November 2006 was widely criticized for performance related issues.

Windows 7 (October, 2009)

Windows 7 made its official debut on October 22, 2009. The OS included enhancements in the form of fast start-up time, Aero Snap, Aero Shake, support for virtual hard disks, a new and improved Windows Media Center, and better security features.


Windows 7

Windows 8

Bill Gates’ vision of the future computing was Touch and voice replacing mouse and keyboard. We already have the touch with Windows 8, a completely redesigned OS built from the ground up.


Windows 8.1 logo

The OS replaces the more traditional Microsoft Windows OS look and feel with a new “Modern Interface” consisting of flat tiles that first debuted in the Windows Phone 7 mobile operating system.


History of Microsoft Windows

From Wikipedia, the free encyclopedia

This article is about the history of Microsoft’s graphical operating system. If you are looking for just a list of all versions made, see List of Microsoft Windows versions.

On November 10, 1983, Microsoft announced Windows, a graphical user interface (GUI) for MS-DOS and a competitor to the Macintosh operating system. The product line eventually changed from a mere GUI for DOS into a fully complete, modern operating system over two lines of development, each with their own separate codebase.

The first versions of Windows (1.0 through to 3.11) were actually just programs run from MS-DOS which then took over the screen and launched an application called Program Manager; later on, Windows 95, though still being based on MS-DOS, was its own operating system, using a 16-bit DOS-based kernel and a 32-bit user space. Windows 95 introduced many staple features that remain in current versions of Windows today, including the Start menu, the taskbar, and Windows Explorer (renamed File Explorer in Windows 8). In 1997, Microsoft released Internet Explorer 4 which included the (at the time) controversial Windows Desktop Update, which aimed to integrate Internet Explorer and the web into the user interface and also brought many new features into Windows, such as the ability to display JPEG images as the desktop wallpaper and single window navigation in Windows Explorer, all of which still exist in Windows today. In 1998, Microsoft released Windows 98, which also included the Windows Desktop Update and Internet Explorer 4 by default. The inclusion of Internet Explorer 4 and the Desktop Update led to an infamous anti-trust case. Windows 98 also included plug and play, which allowed devices to simply work when plugged in instead of requiring a system reboot, and USB support out of the box, which was previously only available in specially updated versions of Windows 95 which were only shipped to OEMs and not available to the general public. Windows ME, the last DOS-based version of Windows, was aimed at consumers and released in 2000. It introduced the Help and Support Center, System Restore, and updated user-friendly versions of the Disk Defragmenter and other system tools.

In 1993, Microsoft released Windows NT 3.1, the first version of the newly developed Windows NT operating system. It was not based on DOS and, as a result, was a fully 32-bit operating system, unlike the hybrid 16-bit kernel, 32-bit applications model used in Windows 95, 98 and Me. At the same time, it introduced NTFS, a file system designed to replace the inferior File Allocation Table (FAT) which was used by DOS and the DOS-based Windows operating systems. In 1996, Windows NT 4.0 was released, which included a fully 32-bit version of Windows Explorer written specifically for it, making the operating system work just like Windows 95. Windows NT was originally designed to be used on high-end systems and servers, however with the release of Windows 2000 (codenamed NT 5.0), many consumer-oriented features from Windows 95 and Windows 98 were included, such as the Windows Desktop Update, Internet Explorer 5, USB support and Windows Media Player. These consumer-oriented features were continued and further extended in Windows XP, which introduced a new theme called Luna, a more user-friendly interface, updated versions of Windows Media Player and Internet Explorer, and extended features from Windows Me, such as the Help and Support Center and System Restore, all while retaining the robustness and stability of Windows 2000’s kernel. Windows Vista focused on securing the Windows operating system against computer viruses and other malicious software by introducing features such as User Account Control, while also including many consumer features such as Windows Aero, updated versions of the standard games (Solitaire, etc.) to show off the 3D capabilities of Vista, Windows Movie Maker, and Windows Mail to replace Outlook Express. Despite this, Windows Vista was critically panned for its poor performance on older hardware and its at-the-time high system requirements. Windows 7, as such, was focused on simplifying Windows Vista. Despite technically having higher system requirements, reviewers noted that it ran better than Windows Vista did. Windows 7 also removed many extra features, such as Windows Movie Maker, Windows Photo Gallery and Windows Mail, instead requiring users download a separate Windows Live Essentials to gain those features and other online services. Windows 8 and Windows 8.1, a free upgrade for Windows 8, introduced many controversial features, such as the removal of the Start menu and the introduction of the Start Screen, the removal of the Aero glass interface in favor of a flat, colored interface as well as the introduction of “Metro” apps (later renamed Universal Windows Platform apps) and the Charms Bar user interface element, all of which were criticized.

The current version of Windows, Windows 10, reintroduced the Start menu, while retaining the Universal Platform apps, but instead allowing them to run in a window instead of always in full screen. Windows 10 was very well received, with many reviewers stating that Windows 10 is what Windows 8 should have been. Windows 10 also marks the last version of Windows to be traditionally released. For the future, Microsoft will no longer release new versions of Windows and instead introduce major updates to the operating system that add new features, so far 3 of which have been released (see Windows 10 section below).

1 Windows 1.x
2 Windows 2.x
3 Windows 3.0
4 OS/2
5 Windows 3.1x
6 Windows NT 3.x
7 Windows 95
8 Windows NT 4.0
9 Windows 98
10 Windows 2000
11 Windows ME
12 Windows XP and Server 2003
12.1 Windows Server 2003
12.2 Windows XP x64 and Server 2003 x64 Editions
12.3 Windows Fundamentals for Legacy PCs
12.4 Windows Home Server
13 Windows Vista and Server 2008
13.1 Windows Server 2008
14 Windows 7 and Server 2008 R2
14.1 Windows Thin PC
15 Windows Home Server 2011
16 Windows 8 and Server 2012
17 Windows 10 and Server 2016
17.1 Windows Server 2016

Windows 1.x

The first independent version of Microsoft Windows, version 1.0, released on November 20, 1985, achieved little popularity. The project was briefly codenamed “Interface Manager” before the windowing system was developed – contrary to popular belief that it was the original name for Windows and Rowland Hanson, the head of marketing at Microsoft, convinced the company that the name Windows would be more appealing to customers.

Windows 1.0 was not a complete operating system, but rather an “operating environment” that extended MS-DOS, and shared the latter’s inherent flaws and problems.

The first version of Microsoft Windows included a simple graphics painting program called Windows Paint; Windows Write, a simple word processor; an appointment calendar; a card-filer; a notepad; a clock; a control panel; a computer terminal; Clipboard; and RAM driver. It also included the MS-DOS Executive and a game called Reversi.

Microsoft had worked with Apple Computer to develop applications for Apple’s new Macintosh computer, which featured a graphical user interface. As part of the related business negotiations, Microsoft had licensed certain aspects of the Macintosh user interface from Apple; in later litigation, a district court summarized these aspects as “screen displays”. In the development of Windows 1.0, Microsoft intentionally limited its borrowing of certain GUI elements from the Macintosh user interface, to comply with its license. For example, windows were only displayed “tiled” on the screen; that is, they could not overlap or overlie one another.

Windows 2.x

Microsoft Windows version 2 came out on December 9, 1987, and proved slightly more popular than its predecessor. Much of the popularity for Windows 2.0 came by way of its inclusion as a “run-time version” with Microsoft’s new graphical applications, Excel and Word for Windows. They could be run from MS-DOS, executing Windows for the duration of their activity, and closing down Windows upon exit.

Microsoft Windows received a major boost around this time when Aldus PageMaker appeared in a Windows version, having previously run only on Macintosh. Some computer historians[who?] date this, the first appearance of a significant and non-Microsoft application for Windows, as the start of the success of Windows.

Versions 2.0x used the real-mode memory model, which confined it to a maximum of 1 megabyte of memory. In such a configuration, it could run under another multitasker like DESQview, which used the 286 protected mode.

Later, two new versions were released: Windows/286 2.1 and Windows/386 2.1. Like prior versions of Windows, Windows/286 2.1 used the real-mode memory model, but was the first version to support the High Memory Area. Windows/386 2.1 had a protected mode kernel with LIM-standard EMS emulation. All Windows and DOS-based applications at the time were real mode, running over the protected mode kernel by using the virtual 8086 mode, which was new with the 80386 processor.

Version 2.03, and later 3.0, faced challenges from Apple over its overlapping windows and other features Apple charged mimicked the ostensibly copyrighted “look and feel” of its operating system and “embodie and generated a copy of the Macintosh” in its OS. Judge William Schwarzer dropped all but 10 of Apple’s 189 claims of copyright infringement, and ruled that most of the remaining 10 were over uncopyrightable ideas.

Windows 3.0

Windows 3.0, released in May 1990, improved capabilities given to native applications. It also allowed users to better multitask older MS-DOS based software compared to Windows/386, thanks to the introduction of virtual memory.

Windows 3.0’s user interface finally resembled a serious competitor to the user interface of the Macintosh computer. PCs had improved graphics by this time, due to VGA video cards, and the protected/enhanced mode allowed Windows applications to use more memory in a more painless manner than their DOS counterparts could. Windows 3.0 could run in real, standard, or 386 enhanced modes, and was compatible with any Intel processor from the 8086/8088 up to the 80286 and 80386. This was the first version to run Windows programs in protected mode, although the 386 enhanced mode kernel was an enhanced version of the protected mode kernel in Windows/386.

Windows 3.0 received two updates. A few months after introduction, Windows 3.0a was released as a maintenance release, resolving bugs and improving stability. A “multimedia” version, Windows 3.0 with Multimedia Extensions 1.0, was released in October 1991. This was bundled with “multimedia upgrade kits”, comprising a CD-ROM drive and a sound card, such as the Creative Labs Sound Blaster Pro. This version was the precursor to the multimedia features available in Windows 3.1 (first released in April 1992) and later, and was part of Microsoft’s specification for the Multimedia PC.

The features listed above and growing market support from application software developers made Windows 3.0 wildly successful, selling around 10 million copies in the two years before the release of version 3.1. Windows 3.0 became a major source of income for Microsoft, and led the company to revise some of its earlier plans. Support was discontinued on December 31, 2001.



OS/2 logo

During the mid to late 1980s, Microsoft and IBM had cooperatively been developing OS/2 as a successor to DOS. OS/2 would take full advantage of the aforementioned protected mode of the Intel 80286 processor and up to 16 MB of memory. OS/2 1.0, released in 1987, supported swapping and multitasking and allowed running of DOS executables.

A GUI, called the Presentation Manager (PM), was not available with OS/2 until version 1.1, released in 1988. Its API was incompatible with Windows. Version 1.2, released in 1989, introduced a new file system, HPFS, to replace the FAT file system.

By the early 1990s, conflicts developed in the Microsoft/IBM relationship. They cooperated with each other in developing their PC operating systems, and had access to each other’s code. Microsoft wanted to further develop Windows, while IBM desired for future work to be based on OS/2. In an attempt to resolve this tension, IBM and Microsoft agreed that IBM would develop OS/2 2.0, to replace OS/2 1.3 and Windows 3.0, while Microsoft would develop a new operating system, OS/2 3.0, to later succeed OS/2 2.0.

This agreement soon fell apart however, and the Microsoft/IBM relationship was terminated. IBM continued to develop OS/2, while Microsoft changed the name of its (as yet unreleased) OS/2 3.0 to Windows NT. Both retained the rights to use OS/2 and Windows technology developed up to the termination of the agreement; Windows NT, however, was to be written anew, mostly independently (see below).

After an interim 1.3 version to fix up many remaining problems with the 1.x series, IBM released OS/2 version 2.0 in 1992. This was a major improvement: it featured a new, object-oriented GUI, the Workplace Shell (WPS), that included a desktop and was considered by many to be OS/2’s best feature. Microsoft would later imitate much of it in Windows 95. Version 2.0 also provided a full 32-bit API, offered smooth multitasking and could take advantage of the 4 gigabytes of address space provided by the Intel 80386. Still, much of the system had 16-bit code internally which required, among other things, device drivers to be 16-bit code also. This was one of the reasons for the chronic shortage of OS/2 drivers for the latest devices. Version 2.0 could also run DOS and Windows 3.0 programs, since IBM had retained the right to use the DOS and Windows code as a result of the breakup.

Windows 3.1x

In response to the impending release of OS/2 2.0, Microsoft developed Windows 3.1 (first released in April 1992), which included several improvements to Windows 3.0, such as display of TrueType scalable fonts (developed jointly with Apple), improved disk performance in 386 Enhanced Mode, multimedia support, and bugfixes. It also removed Real Mode, and only ran on an 80286 or better processor. Later Microsoft also released Windows 3.11, a touch-up to Windows 3.1 which included all of the patches and updates that followed the release of Windows 3.1 in 1992.

In 1992 and 1993, Microsoft released Windows for Workgroups (WfW), which was available both as an add-on for existing Windows 3.1 installations and in a version that included the base Windows environment and the networking extensions all in one package. Windows for Workgroups included improved network drivers and protocol stacks, and support for peer-to-peer networking. There were two versions of Windows for Workgroups, WfW 3.1 and WfW 3.11. Unlike prior versions, Windows for Workgroups 3.11 ran in 386 Enhanced Mode only, and needed at least an 80386SX processor. One optional download for WfW was the “Wolverine” TCP/IP protocol stack, which allowed for easy access to the Internet through corporate networks.

All these versions continued version 3.0’s impressive sales pace. Even though the 3.1x series still lacked most of the important features of OS/2, such as long file names, a desktop, or protection of the system against misbehaving applications, Microsoft quickly took over the OS and GUI markets for the IBM PC. The Windows API became the de facto standard for consumer software.

Windows NT 3.x

Main articles: Windows NT, Windows NT 3.1, Windows NT 3.5, and Windows NT 3.51
Meanwhile, Microsoft continued to develop Windows NT. The main architect of the system was Dave Cutler, one of the chief architects of VMS at Digital Equipment Corporation (later acquired by Compaq, now part of Hewlett-Packard). Microsoft hired him in October 1988 to create a successor to OS/2, but Cutler created a completely new system instead. Cutler had been developing a follow-on to VMS at DEC called Mica, and when DEC dropped the project he brought the expertise and around 20 engineers with him to Microsoft. DEC also believed he brought Mica’s code to Microsoft and sued. Microsoft eventually paid US$150 million and agreed to support DEC’s Alpha CPU chip in NT.

Windows NT Workstation (Microsoft marketing wanted Windows NT to appear to be a continuation of Windows 3.1) arrived in Beta form to developers at the July 1992 Professional Developers Conference in San Francisco. Microsoft announced at the conference its intentions to develop a successor to both Windows NT and Windows 3.1’s replacement (Windows 95, codenamed Chicago), which would unify the two into one operating system. This successor was codenamed Cairo. In hindsight, Cairo was a much more difficult project than Microsoft had anticipated and, as a result, NT and Chicago would not be unified until Windows XP—albeit Windows 2000, oriented to business, had already unified most of the system’s bolts and gears, it was XP that was sold to home consumers like Windows 95 and came to be viewed as the final unified OS. Parts of Cairo have still not made it into Windows as of 2017 – most notably, the WinFS file system, which was the much touted Object File System of Cairo. Microsoft announced that they have discontinued the separate release of WinFS for Windows XP and Windows Vista and will gradually incorporate the technologies developed for WinFS in other products and technologies, notably Microsoft SQL Server.

Driver support was lacking due to the increased programming difficulty in dealing with NT’s superior hardware abstraction model. This problem plagued the NT line all the way through Windows 2000. Programmers complained that it was too hard to write drivers for NT, and hardware developers were not going to go through the trouble of developing drivers for a small segment of the market. Additionally, although allowing for good performance and fuller exploitation of system resources, it was also resource-intensive on limited hardware, and thus was only suitable for larger, more expensive machines.

However, these same features made Windows NT perfect for the LAN server market (which in 1993 was experiencing a rapid boom, as office networking was becoming common). NT also had advanced network connectivity options and NTFS, an efficient file system. Windows NT version 3.51 was Microsoft’s entry into this field, and took away market share from Novell (the dominant player) in the following years.

One of Microsoft’s biggest advances initially developed for Windows NT was a new 32-bit API, to replace the legacy 16-bit Windows API. This API was called Win32, and from then on Microsoft referred to the older 16-bit API as Win16. The Win32 API had three levels implementations: the complete one for Windows NT, a subset for Chicago (originally called Win32c) missing features primarily of interest to enterprise customers (at the time) such as security and Unicode support, and a more limited subset called Win32s which could be used on Windows 3.1 systems. Thus Microsoft sought to ensure some degree of compatibility between the Chicago design and Windows NT, even though the two systems had radically different internal architectures. Windows NT was the first Windows operating system based on a hybrid kernel.

As released, Windows NT 3.x went through three versions (3.1, 3.5, and 3.51); changes were primarily internal and reflected back end changes. The 3.5 release added support for new types of hardware and improved performance and data reliability; the 3.51 release was primarily to update the Win32 APIs to be compatible with software being written for the Win32c APIs in what became Windows 95.

Windows 95

After Windows 3.11, Microsoft began to develop a new consumer oriented version of the operating system codenamed Chicago. Chicago was designed to have support for 32-bit preemptive multitasking like OS/2 and Windows NT, although a 16-bit kernel would remain for the sake of backward compatibility. The Win32 API first introduced with Windows NT was adopted as the standard 32-bit programming interface, with Win16 compatibility being preserved through a technique known as “thunking”. A new object oriented GUI was not originally planned as part of the release, although elements of the Cairo user interface were borrowed and added as other aspects of the release (notably Plug and Play) slipped.

Microsoft did not change all of the Windows code to 32-bit; parts of it remained 16-bit (albeit not directly using real mode) for reasons of compatibility, performance, and development time. Additionally it was necessary to carry over design decisions from earlier versions of Windows for reasons of backwards compatibility, even if these design decisions no longer matched a more modern computing environment. These factors eventually began to impact the operating system’s efficiency and stability.

Microsoft marketing adopted Windows 95 as the product name for Chicago when it was released on August 24, 1995. Microsoft had a double gain from its release: first, it made it impossible for consumers to run Windows 95 on a cheaper, non-Microsoft DOS; secondly, although traces of DOS were never completely removed from the system and MS DOS 7 would be loaded briefly as a part of the booting process, Windows 95 applications ran solely in 386 enhanced mode, with a flat 32-bit address space and virtual memory. These features make it possible for Win32 applications to address up to 2 gigabytes of virtual RAM (with another 2 GB reserved for the operating system), and in theory prevented them from inadvertently corrupting the memory space of other Win32 applications. In this respect the functionality of Windows 95 moved closer to Windows NT, although Windows 95/98/ME did not support more than 512 megabytes of physical RAM without obscure system tweaks.

IBM continued to market OS/2, producing later versions in OS/2 3.0 and 4.0 (also called Warp). Responding to complaints about OS/2 2.0’s high demands on computer hardware, version 3.0 was significantly optimized both for speed and size. Before Windows 95 was released, OS/2 Warp 3.0 was even shipped preinstalled with several large German hardware vendor chains. However, with the release of Windows 95, OS/2 began to lose market share.

It is probably impossible to choose one specific reason why OS/2 failed to gain much market share. While OS/2 continued to run Windows 3.1 applications, it lacked support for anything but the Win32s subset of Win32 API (see above). Unlike with Windows 3.1, IBM did not have access to the source code for Windows 95 and was unwilling to commit the time and resources to emulate the moving target of the Win32 API. IBM later introduced OS/2 into the United States v. Microsoft case, blaming unfair marketing tactics on Microsoft’s part.

Microsoft went on to release five different versions of Windows 95:

  • Windows 95 – original release
  • Windows 95 A – included Windows 95 OSR1 slipstreamed into the installation.
  • Windows 95 B – (OSR2) included several major enhancements, Internet Explorer (IE) 3.0 and full FAT32 file system support.
  • Windows 95 B USB – (OSR2.1) included basic USB support.
  • Windows 95 C – (OSR2.5) included all the above features, plus IE 4.0. This was the last 95 version produced.

OSR2, OSR2.1, and OSR2.5 were not released to the general public; rather, they were available only to OEMs that would preload the OS onto computers. Some companies sold new hard drives with OSR2 preinstalled (officially justifying this as needed due to the hard drive’s capacity).

The first Microsoft Plus! add-on pack was sold for Windows 95.

Windows NT 4.0

Windows NT 4.0 was the successor of 3.51 (1995) and 3.5 (1994). Microsoft released Windows NT 4.0 to manufacturing in July 1996, one year after the release of Windows 95. Major new features included the new Explorer shell from Windows 95, scalability and feature improvements to the core architecture, kernel, USER32, COM and MSRPC.

Windows NT 4.0 came in four versions:

  • Windows NT 4.0 Workstation
  • Windows NT 4.0 Server
  • Windows NT 4.0 Server, Enterprise Edition (includes support for 8-way SMP and clustering)
  • Windows NT 4.0 Terminal Server

Windows 98


Windows 98 desktop

On June 25, 1998, Microsoft released Windows 98 (codenamed Memphis). It included new hardware drivers and the FAT32 file system which supports disk partitions that are larger than 2 GB (first introduced in Windows 95 OSR2). USB support in Windows 98 is marketed as a vast improvement over Windows 95. The release continued the controversial inclusion of the Internet Explorer browser with the operating system that started with Windows 95 OEM Service Release 1. The action eventually led to the filing of the United States v. Microsoft case, dealing with the question of whether Microsoft was introducing unfair practices into the market in an effort to eliminate competition from other companies such as Netscape.

In 1999, Microsoft released Windows 98 Second Edition, an interim release. One of the more notable new features was the addition of Internet Connection Sharing, a form of network address translation, allowing several machines on a LAN (Local Area Network) to share a single Internet connection. Hardware support through device drivers was increased and this version shipped with Internet Explorer 5. Many minor problems that existed in the first edition were fixed making it, according to many, the most stable release of the Windows 9x family.

Windows 2000

Microsoft released Windows 2000 on February 17, 2000. It has the version number Windows NT 5.0. Windows 2000 has had four official service packs. It was successfully deployed both on the server and the workstation markets. Amongst Windows 2000’s most significant new features was Active Directory, a near-complete replacement of the NT 4.0 Windows Server domain model, which built on industry-standard technologies like DNS, LDAP, and Kerberos to connect machines to one another. Terminal Services, previously only available as a separate edition of NT 4, was expanded to all server versions. A number of features from Windows 98 were incorporated also, such as an improved Device Manager, Windows Media Player, and a revised DirectX that made it possible for the first time for many modern games to work on the NT kernel. Windows 2000 is also the last NT-kernel Windows operating system to lack product activation.

While Windows 2000 upgrades were available for Windows 95 and Windows 98, it was not intended for home users.

Windows 2000 was available in four editions:

  • Windows 2000 Professional
  • Windows 2000 Server
  • Windows 2000 Advanced Server
  • Windows 2000 Datacenter Server

Windows ME


Windows ME Desktop

In September 2000, Microsoft released a successor to Windows 98 called Windows ME, short for “Millennium Edition”. It was the last DOS-based operating system from Microsoft. Windows ME introduced a new multimedia-editing application called Windows Movie Maker, came standard with Internet Explorer 5.5 and Windows Media Player 7, and debuted the first version of System Restore – a recovery utility that enables the operating system to revert system files back to a prior date and time. System Restore was a notable feature that would continue to thrive in later versions of Windows, including XP, Vista, and Windows 7.

Windows ME was conceived as a quick one-year project that served as a stopgap release between Windows 98 and Windows XP. Many of the new features were available from the Windows Update site as updates for older Windows versions (System Restore and Windows Movie Maker were exceptions). Windows ME was criticized for stability issues, as well as for lacking real mode DOS support, to the point of being referred to as the “Mistake Edition” or “Many Errors.” Windows ME was the last operating system to be based on the Windows 9x (monolithic) kernel and MS-DOS.

Windows XP and Server 2003


Windows XP Desktop

On October 25, 2001, Microsoft released Windows XP (codenamed “Whistler”). The merging of the Windows NT/2000 and Windows 95/98/Me lines was finally achieved with Windows XP. Windows XP uses the Windows NT 5.1 kernel, marking the entrance of the Windows NT core to the consumer market, to replace the aging 16/32-bit branch. The initial release met with considerable criticism, particularly in the area of security, leading to the release of three major Service Packs. Windows XP SP1 was released in September 2002, SP2 came out in August 2004 and SP3 came out in April 2008. Service Pack 2 provided significant improvements and encouraged widespread adoption of XP among both home and business users. Windows XP lasted longer as Microsoft’s flagship operating system than any other version of Windows, from October 25, 2001 to January 30, 2007 when it was succeeded by Windows Vista.

Windows XP is available in a number of versions:

  • Windows XP Home Edition, for home desktops and laptops – lacked features such as joining Active Directory Domain, Remote Desktop Server and Internet Information Services Server.
    • Windows XP Home Edition N, as above, but without a default installation of Windows Media Player, as mandated by a European Union ruling
  • Windows XP Professional, for business and power users contained all features in Home Edition.
    • Windows XP Professional N, as above, but without a default installation of Windows Media Player, as mandated by a European Union ruling
  • Windows XP Media Center Edition (MCE), released in October 2002 for desktops and notebooks with an emphasis on home entertainment. Contained all features offered in Windows XP Professional and the Windows Media Center. Subsequent versions are the same but have an updated Windows Media Center.
    • Windows XP Media Center Edition 2003
    • Windows XP Media Center Edition 2004
    • Windows XP Media Center Edition 2005, released on October 12, 2004. Included Windows XP Service Pack 2, the Royale Windows Theme and joining a Windows Active Directory Domain is disabled. The Aquarium, Da Vinci, Nature and Space themes are retained from Windows XP Plus!
  • Windows XP Tablet PC Edition, for tablet PCs
    • Windows XP Tablet PC Edition 2005
  • Windows XP Embedded, for embedded systems
  • Windows XP Starter Edition, for new computer users in developing countries
  • Windows XP Professional x64 Edition, released on April 25, 2005 for home and workstation systems utilizing 64-bit processors based on the x86-64 instruction set originally developed by AMD as AMD64; Intel calls their version Intel 64. Internally, XP x64 was a somewhat updated OS based on the Server 2003 code line.
  • Windows XP 64-bit Edition, is a version for Intel’s Itanium line of processors; maintains 32-bit compatibility solely through a software emulator. It is roughly analogous to Windows XP Professional in features. It was discontinued in September 2005 when the last vendor of Itanium workstations stopped shipping Itanium systems marketed as “Workstations”.

Windows Server 2003


Windows Server 2003 Desktop

On April 25, 2003 Microsoft launched Windows Server 2003, a notable update to Windows 2000 Server encompassing many new security features, a new “Manage Your Server” wizard that simplifies configuring a machine for specific roles, and improved performance. It has the version number NT 5.2. A few services not essential for server environments are disabled by default for stability reasons, most noticeable are the “Windows Audio” and “Themes” services; users have to enable them manually to get sound or the “Luna” look as per Windows XP. The hardware acceleration for display is also turned off by default, users have to turn the acceleration level up themselves if they trust the display card driver.

December 2005, Microsoft released Windows Server 2003 R2, which is actually Windows Server 2003 with SP1 (Service Pack 1) plus an add-on package. Among the new features are a number of management features for branch offices, file serving, printing and company-wide identity integration.

Windows Server 2003 is available in six editions:

  • Web Edition (32-bit)
  • Enterprise Edition (32 and 64-bit)
  • Datacenter Edition (32 and 64-bit)
  • Small Business Server (32-bit)
  • Storage Server (OEM channel only).

Windows Server 2003 R2, an update of Windows Server 2003, was released to manufacturing on December 6, 2005. It is distributed on two CDs, with one CD being the Windows Server 2003 SP1 CD. The other CD adds many optionally installable features for Windows Server 2003. The R2 update was released for all x86 and x64 versions, except Windows Server 2003 R2 Enterprise Edition, which was not released for Itanium.

Windows XP x64 and Server 2003 x64 Editions

On April 25, 2005, Microsoft released Windows XP Professional x64 Edition and Windows Server 2003, x64 Editions in Standard, Enterprise and Datacenter SKUs. Windows XP Professional x64 Edition is an edition of Windows XP for x86-64 personal computers. It is designed to use the expanded 64-bit memory address space provided by the x86-64 architecture.

Windows XP Professional x64 Edition is based on the Windows Server 2003 codebase; with the server features removed and client features added. Both Windows Server 2003 x64 and Windows XP Professional x64 Edition use identical kernels.

Windows XP Professional x64 Edition is not to be confused with Windows XP 64-bit Edition, as the latter was designed for Intel Itanium processors. During the initial development phases, Windows XP Professional x64 Edition was named Windows XP 64-Bit Edition for 64-Bit Extended Systems.

Windows Fundamentals for Legacy PCs


Windows Fundamentals for Legacy PCs Desktop

In July 2005, Microsoft released a thin-client version of Windows XP Service Pack 2, called Windows Fundamentals for Legacy PCs (WinFLP). It is only available to Software Assurance customers. The aim of WinFLP is to give companies a viable upgrade option for older PCs that are running Windows 95, 98, and ME that will be supported with patches and updates for the next several years. Most user applications will typically be run on a remote machine using Terminal Services or Citrix.

Windows Home Server

Windows Home Server (codenamed Q, Quattro) is a server product based on Windows Server 2003, designed for consumer use. The system was announced on January 7, 2007 by Russel Adolfo. Windows Home Server can be configured and monitored using a console program that can be installed on a client PC. Such features as Media Sharing, local and remote drive backup and file duplication are all listed as features. The release of Windows Home Server Power Pack 3 added support for Windows 7 to Windows Home Server.

Windows Vista and Server 2008


Windows Vista Desktop

Main articles: Windows Vista, Features new to Windows Vista, Development of Windows Vista, Criticisms of Windows Vista, and List of features removed in Windows Vista
Windows Vista was released on November 30, 2006 to business customers – consumer versions followed on January 30, 2007. Windows Vista intended to have enhanced security by introducing a new restricted user mode called User Account Control, replacing the “administrator-by-default” philosophy of Windows XP. Vista was the target of much criticism and negative press, and in general was not well regarded; this was seen as leading to the relatively swift release of Windows 7.

One major difference between Vista and earlier versions of Windows, Windows 95 and later, is that the original start button was replaced with the Windows icon in a circle (called the Start Orb). Vista also features new graphics features, the Windows Aero GUI, new applications (such as Windows Calendar, Windows DVD Maker and some new games including Chess, Mahjong, and Purble Place), Internet Explorer 7, Windows Media Player 11, and a large number of underlying architectural changes including Windows Powershell being shipped with the operating system, which many believed to have taken place in Windows 7’s architecture and later. Windows Vista has the version number NT 6.0. Since its release, Windows Vista has had two service packs.

Windows Vista ships in six editions:

  • Starter (only available in developing countries)
  • Home Basic
  • Home Premium
  • Business
  • Enterprise (only available to large business and enterprise)
  • Ultimate (combines both Home Premium and Enterprise)

All editions (except Starter edition) are currently available in both 32-bit and 64-bit versions. The biggest advantage of the 64-bit version is breaking the 4 gigabyte memory barrier, which 32-bit computers cannot fully access.

Windows Server 2008

Windows Server 2008, released on February 27, 2008, was originally known as Windows Server Codename “Longhorn”. Windows Server 2008 builds on the technological and security advances first introduced with Windows Vista, and is significantly more modular than its predecessor, Windows Server 2003.

Windows Server 2008 ships in ten editions:

  • Windows Server 2008 Standard Edition (32-bit and 64-bit)
  • Windows Server 2008 Enterprise Edition (32-bit and 64-bit)
  • Windows Server 2008 Datacenter Edition (32-bit and 64-bit)
  • Windows HPC Server 2008
  • Windows Web Server 2008 (32-bit and 64-bit)
  • Windows Storage Server 2008 (32-bit and 64-bit)
  • Windows Small Business Server 2008 (64-bit only)
  • Windows Essential Business Server 2008 (32-bit and 64-bit)
  • Windows Server 2008 for Itanium-based Systems
  • Windows Server 2008 Foundation Server

Windows 7 and Server 2008 R2


Windows 7 Desktop

Windows 7 was released to manufacturing on July 22, 2009, and reached general retail availability on October 22, 2009. It was previously known by the codenames Blackcomb and Vienna. Windows 7 has the version number NT 6.1. Since its release, Windows 7 has had one service pack.

Some features of Windows 7 are faster booting, Device Stage, Windows PowerShell, less obtrusive User Account Control, multi-touch, and improved window management. Features included with Windows Vista and not in Windows 7 include the sidebar (although gadgets remain) and several programs that were removed in favor of downloading their Windows Live counterparts.

Windows 7 ships in six editions:

  • Starter (available worldwide)
  • Home Basic
  • Home Premium
  • Professional
  • Enterprise (available to volume-license business customers only)
  • Ultimate

In some countries (Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, United Kingdom, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and Switzerland), there are other editions that lack some features such as Windows Media Player, Windows Media Center and Internet Explorer – these editions were called names such as “Windows 7 N.” Microsoft focuses on selling Windows 7 Home Premium and Professional. All editions, except the Starter edition, are available in both 32-bit and 64-bit versions. Unlike the corresponding Vista editions, the Professional and Enterprise editions are supersets of the Home Premium edition.

At the Professional Developers Conference (PDC) 2008, Microsoft also announced Windows Server 2008 R2, as the server variant of Windows 7. Windows Server 2008 R2 ships in 64-bit versions (x64 and Itanium) only.

Windows Thin PC

In 2010, Microsoft released Windows Thin PC or WinTPC, which is a feature- and size-reduced locked-down version of Windows 7 expressly designed to turn older PCs into thin clients. WinTPC is available for software assurance customers and relies on cloud computing in a business network. Wireless operation is supported since WinTPC has full wireless stack integration, but wireless operation may not be as good as the operation on a wired connection.

Windows Home Server 2011

Windows Home Server 2011 code named ‘Vail’ was released on April 6, 2011. Windows Home Server 2011 is built on the Windows Server 2008 R2 code base and removed the Drive Extender drive pooling technology in the original Windows Home Server release. Windows Home Server 2011 is considered a “major release”. Its predecessor was built on Windows Server 2003. WHS 2011 only supports x86-64 hardware.

Microsoft decided to discontinue Windows Home Server 2011 on July 5, 2012 while including its features into Windows Server 2012 Essentials. Windows Home Server 2011 was supported until April 12, 2016.

Windows 8 and Server 2012


Screenshot of the Start screen on Windows 8.1 with Update 1

On October 26, 2012, Microsoft released Windows 8 to the public. One edition, Windows RT, runs on some system-on-a-chip devices with mobile 32-bit ARM (ARMv7) processors. Windows 8 features a redesigned user interface, designed to make it easier for touchscreen users to use Windows. The interface introduced an updated Start menu known as the Start screen, and a new full-screen application platform. The desktop interface is also present for running windowed applications, although Windows RT will not run any desktop applications not included in the system. On the Building Windows 8 blog, it was announced that a computer running Windows 8 can boot up much faster than Windows 7. New features also include USB 3.0 support, the Windows Store, the ability to run from USB drives with Windows To Go, and others. Windows 8 was given the kernel number NT 6.2, with its successor 8.1 receiving the kernel number 6.3. So far, neither has had any service packs yet, although many consider Windows 8.1 to be a service pack for Windows 8.

Windows 8 is available in the following editions:

  • Windows 8
  • Windows 8 Pro
  • Windows 8 Enterprise
  • Windows RT

The first public preview of Windows Server 2012 and was also shown by Microsoft at the 2011 Microsoft Worldwide Partner Conference.

Windows 8 Release Preview and Windows Server 2012 Release Candidate were both released on May 31, 2012. Product development on Windows 8 was completed on August 1, 2012, and it was released to manufacturing the same day. Windows Server 2012 went on sale to the public on September 4, 2012. Windows 8 went on sale October 26, 2012.

Windows 8.1 and Windows Server 2012 R2 were released on October 17, 2013. Windows 8.1 is available as an update in the Windows store for Windows 8 users only and also available to download for clean installation. The update adds new options for resizing the live tiles on the Start screen.

Windows 10 and Server 2016


Windows 10 Fall Creators Update, with the desktop, the Start menu, and the notification center shown

Windows 10, codenamed Threshold, is the current release of the Microsoft Windows operating system. Unveiled on September 30, 2014, it was released on July 29, 2015. It was distributed without charge to Windows 7 and 8.1 users for one year after release. A number of new features like Cortana, the Microsoft Edge web browser, the ability to view Windows Store apps as a window instead of fullscreen, virtual desktops, revamped core apps, Continuum, and a unified Settings app were all features debuted in Windows 10. Microsoft has announced that Windows 10 will be the last major version of its series of operating systems to be released. Instead, Microsoft will release major updates to the operating system via download or in Windows Update, similar to the way updates are delivered in macOS.

So far, three major versions have been released, and one has been announced for release in 2017:

  • Version 1507, the original version of Windows 10, codenamed Threshold 1 and released in July 2015. Kernel version number: 10.0.10240.
  • Version 1511, announced as the November Update and codenamed Threshold 2. It was released in November 2015. This update added many visual tweaks, such as more consistent context menus and the ability to change the color of window titlebars. Windows 10 can now be activated with a product key for Windows 7 and later, thus simplifying the activation process and essentially making Windows 10 free for anyone who has Windows 7 or later, even after the free upgrade period ended. A “Find My Device” feature was added, allowing users to track their devices if they lose them, similar to the Find My iPhone service that Apple offers. Controversially, the Start menu now displays “featured apps”. A few tweaks were added to Microsoft Edge, including tab previews and the ability to sync the browser with other devices running Windows 10. Kernel version number: 10.0.10586.
  • Version 1607, announced as the Anniversary Update and codenamed Redstone 1. It is the first of 4 planned updates with the “Redstone” codename. Its version number, 1607, means that it was supposed to launch in July 2016, however it was delayed until August 2016. Tons of new features were included in the version, including more integration with Cortana, a dark theme, browser extension support for Microsoft Edge, click-to-play Flash by default, tab pinning, web notifications, swipe navigation in Edge, and the ability for Windows Hello to use a fingerprint sensor to sign into apps and websites, similar to Touch ID on the iPhone. Also added was Windows Ink, which improves digital inking in many apps, and the Windows Ink Workspace which lists pen-compatible apps, as well as quick shortcuts to a sticky notes app and a sketchpad. Microsoft, through their partnership with Canonical, integrated a full Ubuntu bash shell via the Windows Subsystem for Linux. Notable tweaks in this version of Windows 10 include the removal of the controversial password-sharing feature of Microsoft’s Wi-Fi Sense service, a slightly redesigned Start menu, Tablet Mode working more like Windows 8, overhauled emoji, improvements to the lock screen, calendar integration in the taskbar, and the Blue Screen of Death now showing a QR code which users can scan to quickly find out what caused the error. This version of Windows 10’s kernel version is 10.0.14393.
  • Version 1703, announced as the Creators Update and codenamed Redstone 2. Planned features for this update include a new Paint 3D application, which allows users to create and modify 3D models, integration with Microsoft’s HoloLens and other “mixed-reality” headsets produced by other manufacturers, Windows MyPeople, which allows users to manage contacts, Xbox game broadcasting, support for newly developed APIs such as WDDM 2.2, Dolby Atmos support, improvements to the Settings app, and more Edge and Cortana improvements. This version will also include tweaks to system apps, such as an address bar in the Registry Editor, Windows PowerShell being the default command line interface instead of the Command Prompt and the Windows Subsystem for Linux being upgraded to support Ubuntu 16.04. This version of Windows 10 was released on 11 April 2017 as a free update.

Windows Server 2016

Windows Server 2016 is a release of the Microsoft Windows Server operating system that was unveiled on September 30, 2014. Windows Server 2016 was officially released at Microsoft’s Ignite Conference, September 26–30, 2016.

Computer Concepts & Applications

History of Computer Development

Essential Introduction to Computers


Operating Systems

Operating Systems and Utility Programs

Chapter 8: Operating Systems and Utility Programs


  1. Describe the two types of software
  2. Understand the startup process for a personal computer
  3. Describe the term user interface
  4. Explain features common to most operating systems
  5. Know the difference between stand-alone operating systems and network operating systems
  6. Identify various stand-alone operating systems
  7. Identify various network operating systems
  8. Recognize devices that use embedded operating systems
  9. Discuss the purpose of the following utilities: file viewer, file compression, diagnostic, uninstaller, disk scanner, disk defragmenter, backup, and screen saver

System software is an essential part of a computer system. This chapter defines system software and discusses two types of system software: operating systems and utility programs. You learn what an operating system is and explore user interfaces, operating systems features, and operating system functions. A variety of popular operating systems are described including DOS, Windows 3.x, Windows 95, Windows 98, Windows 2000, Windows XP, Windows CE, the Mac OS, OS/2, UNIX, Linux, and NetWare. You discover what happens when they start a computer and why a boot disk is important. Finally, a number of utility programs are explained.

1 | Describe The Two Types Of Software

Two types of software are application software and system software. Application software consists of programs that perform specific tasks for users, such as a word processing program, e-mail program, or Web browser. System software consists of the programs that control the operations of a computer and its devices. The two types of system software are operating systems and utility programs. An operating system (OS) is a set of programs containing instructions that coordinate all the activities among computer hardware devices. A utility program performs a specific task, usually related to managing a computer, its devices, or its programs.

2 | Understand The Startup Process For A Personal Computer

Booting is the process of starting or restarting a computer. When you turn on the computer, the power supply sends an electrical signal to devices located in the system unit. The processor chip resets itself and looks for the ROM chip that contains the BIOS (basic input/output system), which is firmware that holds the startup instructions. The BIOS executes the power-on self test (POST) to make sure hardware is connected properly and operating correctly. The POST results are compared with data in a CMOS chip on the motherboard. If the POST completes successfully, the BIOS searches for specific operating system files called system files. Once located, the boot drive (the drive from which your personal computer starts), loads the system files from storage (the hard disk – usually drive C) into memory (RAM) and executes them. Next, the kernel of the operating system loads into memory and takes control of the computer. The operating system loads configuration information. In Windows XP, the registry consists of several file that contain the system configuration information. When complete, the Windows XP desktop and icons display, and programs in the StartUp folder are executed.

3 | Describe The Term User Interface

A user interface controls how you enter data and instructions and how information displays on the screen. Two types of user interfaces are command-line and graphical. With a command-line interface, you type keywords or press special keys to enter data or instructions. A graphical user interface (GUI) allows you to use menus and visual images such as icons, buttons, and other graphical objects to issue commands. A menu is a set of commands from which you can choose. An icon is a small image that represents a program, an instruction, a file, or some other object.

4 | Explain Features Common To Most Operating Systems

Most operating systems perform similar functions that include managing programs, managing memory, scheduling jobs, configuring devices, accessing the Web, monitoring performance, providing housekeeping services, and administering security. Managing programs directly affects your productivity. A single user/single tasking operating system allows only one user to run one program at a time. A multitasking operating system allows a single user to work on two or more applications that reside in memory at the same time. A multi-user operating system enables two or more users to run a program simultaneously.

A multiprocessing operating system can support two or more CPUs running programs at the same time. Managing memory involves assigning items to an area of memory while they are being processed. The purpose of memory management is to optimize use of random access memory (RAM). With virtual memory (VM), the operating system optimizes memory by allocating a portion of a storage medium, usually the hard disk, to function as additional RAM. Scheduling jobs (operations the processor manages) involves determining the order in which jobs are processed.

Spooling increases efficiency by placing print jobs in a buffer (an area of memory or storage where data resides while waiting to be transferred) until the printer is ready, freeing the processor for other tasks. Configuring devices establishes communication with each device in the computer. A device driver is a small program that tells the operating system how to communicate with a device. Accessing the Web may entail including a Web browser and e-mail program in the operating system. Monitoring performance helps to identify and solve system problems.

A performance monitor is a program that assesses and reports information about various system resources and devices. Providing housekeeping services entails performing storage and file management functions. A file manager performs such functions as formatting and copying disks; listing the files on a storage medium; checking the amount of used and unused space on a storage medium; organizing, copying, deleting, moving, and sorting files; and creating shortcuts (icons on the desktop that run a program when clicked).

Administering security involves establishing user accounts on a network. Each account typically requires a user name and a password to log on, or access, the network.

5 | Know The Difference Between Stand-Alone Operating Systems And Network Operating Systems

A stand-alone operating system is a complete operating system that works on a desktop or notebook computer. A network operating system (also called network OS or NOS) is an operating system that supports a network. A network is a collection of computers and devices connected together via communications media and devices such as cables, telephone lines, and modems. In some networks, the server is the computer that controls access to the hardware and software on a network and provides a centralized storage area. The other computers on the network, called clients, rely on the server(s) for resources.

6 | Identify Various Stand-Alone Operating Systems

Stand-alone operating systems include DOS, Windows 3.x, Windows 95, Windows NT Workstation, Windows 98, Windows 2000 Professional, Windows Millennium Edition, Windows XP Home Edition, Windows XP Professional Edition, Mac OS, OS/2 Warp Client, UNIX, and Linux. UNIX and Linux also function as network operating systems.

DOS (Disk Operating System) refers to several single user, command-line and menu-driven operating systems developed in the early 1980s for personal computers. Windows 3.x refers to early operating environments that, although not operating systems, provided a graphical user interface to work in combination with DOS and simplify its use. Windows 95 is a true multitasking operating system – not an operating environment – with an improved graphical interface. Windows NT Workstation is a client operating system that can connect to a Windows NT Server. Developed as an upgrade to Windows 95, the Windows 98 operating system is easier to use and more integrated with the Internet. Windows 98 includes Microsoft Internet Explorer, a popular Web browser, Windows Explorer, a file manager, and an Active Desktop™ that works similarly to Web links. Windows 2000 Professional is a complete, reliable multitasking client operating system for business desktop and business notebook computers. Windows Millennium Edition is an operating system that has features specifically for the home user. Windows XP is Microsoft’s fastest, most reliable Windows operating system, providing quicker startup, better performance, and a new, simplified visual look. Windows XP Home Edition is an upgrade to Windows Millennium Edition, while Windows XP Professional Edition is an upgrade to Windows 2000 Professional.

The Mac OS, the latest version of the Macintosh operating system (the first commercially successful graphical user interface), is a multitasking operating system available only on Apple computers. OS/2 Warp Client is IBM’s GUI multitasking client operating system that supports networking, Java, the Internet, and speech recognition.

7 | Identify Various Network Operating Systems

Network operating systems include NetWare, Windows NT Server, Windows 2000 Server, Windows .NET Server, OS/2 Warp Server for E-business, UNIX, Linux, and Solaris™. Novell’s NetWare is a widely used network operating system designed for client/server networks. Windows NT Server is the operating system used by servers in the Windows NT client/server network environment. The Windows 2000 Server family consists of three products: Windows 2000 Server (for the typical business network), Windows 2000 Advanced Server (for e-commerce applications), and Windows 2000 Database server (for demanding, large-scale applications). Windows .NET Server is an upgrade to Windows 2000 Server. The Windows .NET Server family includes four products: Windows .NET Standard Server (for the typical small- to medium-sized business network), Windows .NET Enterprise Server (for medium- to large-sized businesses, including those with e-commerce applications), Windows .NET Datacenter (for business with huge volumes of transactions and large-scale databases), and Windows .NET Web Server (for Web server and Web hosting businesses).

OS/2 Warp Server for E-business is IBM’s network operating system designed for all sizes of business.

UNIX is a multitasking, command-line operating system implemented on many different types of computers. Because it is both a stand-alone operating system and a network operating system, some call UNIX a multipurpose operating system. Linux is a popular, free, multitasking UNIX-type operating system. Solaris™, a version of UNIX developed by Sun Microsystems, is a network operating system designed for e-commerce applications.

8 | Recognize Devices That Use Embedded Operating Systems

The operating system on most handheld computers and small devices, called an embedded operating system, resides on a ROM chip. Popular embedded operating systems include Windows CE, Pocket PC OS, and Palm OS®. Windows CE is a scaled-down Windows operating system designed for use on wireless communications devices and smaller computers such as handheld computers, in-vehicle devices, and Web-enabled devices. Pocket PC OS is a scaled-down operating system developed by Microsoft that works on a specific type of handheld computer, called a Pocket PC. The Palm OS® is the operating system used on Palm handheld computers from Palm, Inc., and Visor handheld computers from Handspring™.

9 | Discuss The Purpose Of The Following Utilities: File Viewer, File Compression, Diagnostic, Uninstaller, Disk Scanner, Disk Defragmenter, Backup, And Screen Saver

Most operating systems include several utility programs that perform specific tasks related to managing a computer, its devices, or its programs. A file viewer is a utility that allows you to display and copy the contents of a file. A file compression utility shrinks the size of a file. A diagnostic utility compiles technical information about a computer’s hardware and certain system software programs and then prepares a report outlining any identified problems. An uninstaller is a utility that removes an application, as well as any associated entries in the system files. A disk scanner is a utility that (1) detects and corrects both physical and logical problems on a hard disk, and (2) searches for and removes unnecessary files.

A disk defragmenter is a utility that reorganizes files and unused space on a computer’s hard disk so data can be accessed more quickly and programs can run faster. A backup utility copies, or backs up, selected files or an entire hard drive onto another disk or tape. A screen saver is a utility that causes the monitor’s screen to display a moving image on a blank screen if no keyboard activity occurs for a specified period.

Expand Your Knowledge

  1. System software
  2. Starting a computer
  3. User interface
  4. Features of operating systems
  5. Stand-alone and network operating system
  6. Stand-alone operating systems
  7. Network operating systems
  8. Embedded operating systems
  9. Utility programs

Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.

1 | System Software

Software is a key component of any information system. Of the total number of corporate dollars spent on computing, the software share is increasing while the hardware share is decreasing. Typically, different sizes of computers use different operating systems, and even the same types of computers may not use the same operating system. The operating system that a computer uses sometimes is called the software platform, or platform. Application software packages often require a specific software platform. A cross-platform application, however, is one that runs on multiple operating systems.

2 | Starting A Computer

When you turn on a computer after it has been powered off, you are performing a cold boot. When you restart a computer that already has been powered on, you are performing a warm boot. Your typically can perform a warm boot by pressing a combination of keys on the keyboard (in Windows, CTRL+ALT+DEL), selecting options from a menu, or pressing a Reset button on the computer.

If you watch the screen closely as the POST is conducted, the value for the total amount of memory can be seen to change as it is measured in the memory test. If the POST results do not match the data on the CMOS chip, an appropriate message should appear. The boot program typically is the first side, first track, and first sector of the hard disk. When you install an operating system, one of the installation steps involves making an emergency disk from which you can start your computer if the hard disk is damaged.

3 | User Interface

You can interact with an operating system directly (as you do when copying files, moving files, formatting disks, and so on) or indirectly (as you do when working with an application program). An operating system is intended to be transparent; that is, it does not have to be understood, considered, or even known. The operating system with which an application program will work is specified on the application software package. The application programs you want to use should be considered before deciding on an operating system, and the operating system must be considered when choosing application software.

A graphical user interface is designed to be easier to use (more user-friendly) than a command-line interface. As an example of this user-friendly nature, consider how a relatively simple task, such as deleting a file, is performed with a command-line interface and with a GUI. With a command-line interface, you might type del followed by the file name in quotation marks. Therefore, you must remember the command, type it correctly, and use the proper syntax. On the other hand, with a GUI you need only select (click) the file name in the file manager window and then click the Delete command on a menu or the Delete button on a toolbar. Although most people find a GUI the easiest interface to use, some long-time computer virtuosos still feel a command-line user interface is more efficient.

4 | Features Of Operating Systems

Early operating systems were single user/single tasking, but today most operating system are multitasking. Multitasking can be cooperative, in which programs switch when they reach a logical break point, or preemptive, in which programs switch based on priority and an allocated amount of time. Early versions of Windows used cooperative multitasking; Windows 95 and subsequent versions use preemptive multitasking. Upon termination, most programs relinquish their space in memory, which then is reallocated by the operating system. Some programs, however, stay in memory after they terminate. As a class, these programs are called TSR (Terminate and Stay Resident) programs.

Virtual memory is employed with multitasking operating systems to maximize the number of programs that can use memory at one time. Paging, or the technique of swapping items between memory and storage, was developed before processors could address directly more than 1 MB of memory. All printers have buffers, and printer manufacturers are eager to sell DRAM. The term spooling comes from the observation that placing print jobs temporarily in a buffer is somewhat like winding thread onto a spool so that it can be used at a later time. Today, adding and configuring devices is easier because most devices support Plug and Play, which means the computer can recognize a new device and automatically load the necessary drivers. A feature of Windows 95, Plug and Play initially was greeted with mixed reviews. In fact, some wags claimed the new technology was more accurately called, “Plug and Pray.”

Processor utilization – the amount of time that the processor is working and not idle – is one way of monitoring system performance. In addition to the programs that come with most operating systems, several utility programs are available to monitor system performance. Formatting a disk is the process of preparing it for reading and writing. Today, most floppy and hard disks are preformatted by the manufacturer. If you format a disk that already contains data, the formatting process erases the file location information, but it does not erase the actual files on the disk. Therefore, if you accidentally format a disk, often you can unformat it with a utility program. System security usually is most important for large systems or networks. For single-user PCs, adequate system security can be a key in the user’s pocket.

5 | Stand-Alone And Network Operating System

Many early operating systems were device dependent and proprietary. Device-dependent operating systems run only on a specific type of computer. Proprietary software is privately owned and limited to a specific vendor or computer mode. Today, the trend is towards device-independent operating systems that run on many manufacturers’ computers. Software that is not proprietary (i.e., that can work with a variety of computer models) sometimes is called portable or generic. Most of the operating systems discussed in this section are portable. When an operating system is proprietary, usually it is to boost hardware sales.

Operating systems for Apple computers and most mainframes initially were proprietary. Steve Wozniak, cofounder of Apple Computers, believes the decision to make its innovative Macintosh operating system proprietary was one of the company’s greatest mistakes. “We had the most beautiful operating system,” Wozniak writes, “but to get it you had to buy our hardware at twice the price.” Wozniak now feels the operating system should have been licensed.

6 | Stand-Alone Operating Systems

Bill Gates, founder of Microsoft and one of the wealthiest men in the world, began his fortune with the MS-DOS operating system. Although developed for IBM, Microsoft retained the rights to the operating system and licensed the source code to several hardware manufacturers, which resulted in multiple variations. An application written for one type of DOS, however, will work with any other variation. A number follows each version of PC-DOS or MS-DOS. The integer portion of the number indicates a major release, while the decimal portion indicates updates. Thus, MS-DOS 6.2 means major version six, which has been updated twice. To a great extent, the popularity of DOS was a result of the large number of applications written to work with the operating system.

Windows 1.0, released in 1985, was Microsoft’s first attempt with a graphical user interface. It was not until five years later, however, with the release of Windows 3.0, that computer users began to take Windows seriously. Windows required 2 MB of memory (with 4 MB recommended) and an 80386 or newer processor, so it could not be used with many older PCs. Nevertheless, because Windows 3.0 was easier to use than DOS, eventually most software was written, and many popular DOS programs were rewritten, to work with Windows.

Despite the advantages of Windows 95 and a heavily-funded promotional campaign, a poll of DOS and Windows 3.x users showed not everyone immediately embraced the new operating system. When asked how likely they were to adopt Windows 95 within the next six months, respondents replied:

  • extremely likely 10%
  • possible 35%
  • not likely 53%
  • don’t know 2%

Why are people often reluctant to adopt a new operating system?

The inclusion of Internet Explorer in the Windows 98 operating system led to an antitrust suit against Microsoft. Prosecutors insisted that the incorporation of a browser was an attempt by Microsoft to eliminate competition from rival Web browsers (such as Netscape Navigator). Microsoft maintained that the addition simply was an enhancement to the operating system. Although Microsoft advertised Windows 98 less heavily than Windows 95, many vendors took up the slack. One retailer offered Windows 98 with the opportunity to buy a new computer for $98. The promotion evidently worked. A buyer waited in line 11 hours for a chance to buy the new operating system and discount computer. When asked if he would have come out simply for Windows 98 (his current computer ran Windows 3.1), he replied, “Not a chance.”

Windows 2000 was released in February, 2000 and was touted as a boon for all businesses, from small companies with no more than two desktop computers to large corporations with vast networks. Windows Millennium is a result of Microsoft’s recognition that the needs of business and home users are different.

For years, the Macintosh operating system had features that made it far easier to use than other operating systems. For example, people could give files sensible names (like “Letter to Grandma”) instead of the cryptic, eight-character strings (like “letgrand.txt”) demanded by DOS and Windows 3.x. While Windows 95 incorporated many of these features, Macintosh devotees still feel their operating system is easier to use. Until recently, the Macintosh operating system was proprietary. In 1994 the operating system was licensed, but experts feel Apple’s promotion has been lukewarm. New standards let IBM computers run Apple software. More than 4,000 applications are designed to run under the Mac OS. Microsoft has developed the more popular Mac OS applications.

IBM supplies OS/2 (Operating System/2) Warp with its high-end personal computers. OS/2 originally was developed jointly by IBM and Microsoft to replace MS-DOS. As an interim measure, Microsoft developed Windows, an operating environment to work with DOS. The eventual popularity of Windows, coupled with the initial poor sales of OS/2, resulted in Microsoft and IBM going their separate ways, with Microsoft concentrating on Windows and IBM continuing to develop OS/2. Features offered in OS/2 Warp include:

  • An enhanced graphical user interface
  • Integrated business application software
  • Speaker-independent speech recognition software
  • Desktop objects that allow users to connect directly to the Internet
  • Integrated Java programming language that allows Java applications to run without a Web browser
  • Support for multiple CPUs using multiprocessing

7 | Network Operating Systems

Many consider UNIX to be the most portable operating system. Although it has some shortcomings, UNIX often is used in “turnkey” systems designed for retail stores, doctors, dentists, veterinarians, and other small- to medium-businesses. Do you know what operating system is mentioned in the film Jurassic Park? UNIX.

Despite the current dominance of Windows, some believe Linux is the operating system of the future. Because Linux is freeware, users can modify and improve the program code. In addition, Linux is capable of running efficiently with less powerful processors, even the 80386. The story of Linux’s originator, Linus Torvalds, is told in the Technology Trailblazer on page 8.25.

8 | Embedded Operating Systems

The latest Palm handheld computer, Palm IIIC, offers a color screen. When paired with a portable, expandable, attachable, nearly full-sized keyboard and file compression software, some reviewers say the Palm IIIC almost can replace a laptop. The Visor handheld computer runs the same operating system as the Palm but offers several additional features – videogames, cell telephone, modem, MP3 player, and two-way pager – at about half the cost.

9 | Utility Programs

Utilities generally reside in storage until summoned by the user or operating system kernel. Microsoft was the target of several lawsuits for allegedly incorporating utility programs developed by others into their DOS operating system. Some versions of DOS were modified because of this litigation. In light of the ever-increasing number of utility programs included with operating systems, will a market remain for separate utility programs?

In addition to the utilities mentioned in this chapter, other Windows 98 utilities include:

  • DirectX – Enhances multimedia capabilities on the computer, providing better playback of different types of multimedia and managing 3-D graphics better than console computers.
  • Drive Converter (FAT 32) – Converts the hard drive to the FAT32 file system, an enhancement that stores data more efficiently, creating extra disk space and helping programs run faster.
  • Registry Checker – Finds and fixes registry problems each time the computer is started, automatically scanning the registry for inconsistent data structures.
    System File Checker – Keeps track of critical files that make the computer run, restoring the files if they are moved or changed.
  • Microsoft Magnifier – Makes the screen more readable by displaying a magnified portion in a separate window and making it possible to alter the color scheme and contrast of the magnification window for easier visibility.

Some stand-alone utilities include:

  • Desktop enhancers – Change the desktop look and organization, allowing users to create and switch between multiple desktops.
  • File conversion – Converts from one file format to another so that a file can be used by another application.
  • Internet organizers – Helps in the management and use of favorite Web sites, searching the Web and reporting on site changes.
  • Antivirus programs – Prevent, detect, and remove computer viruses. Viruses and antivirus programs are explored in Chapter 12.

Some utility programs are used primarily by select groups. For example, text editors — utility programs that make it easy to work with lists and records — are popular with programmers and people who work with databases. PC Tools and Norton Utilities are popular utility software packages for personal computers.

Timeline of Microsoft Windows


The Windows Family Tree

Desktop and Server


Timeline of Windows CE Development



Timeline of Windows CE Development


List of Microsoft OPerating Systems [Microsoft Corporation]

  • Xenix (licensed version of Unix; licensed to SCO in 1987)
  • MSX-DOS (developed by MS Japan for the MSX 8-bit computer)
  • MS-DOS (developed jointly with IBM, versions 1.0–6.22)
  • Windows (16-bit and 32-bit preemptive and cooperative multitasking, running atop MS-DOS)
    • Windows 1.0 (Windows 1)
    • Windows 2.0 (Windows 2 – separate version for i386 processor)
    • Windows 3.0 (Windows 3)
    • Windows 3.1x (Windows 3.1)
    • Windows for Workgroups 3.1 (Codename Snowball)
    • Windows 3.2 (Chinese-only release)
    • Windows for Workgroups 3.11
    • Windows 95 (codename Chicago – Windows 4.0)
    • Windows 98 (codename Memphis – Windows 4.1)
    • Windows Millennium Edition (Windows ME – Windows 4.9)
  • Windows NT (Full 32-bit or 64-bit kernel, not dependent on MS-DOS)
    • Windows NT 3.1
    • Windows NT 3.5
    • Windows NT 3.51
    • Windows NT 4.0
    • Windows 2000 (Windows NT 5.0)
    • Windows XP (Windows NT 5.1)
    • Windows Server 2003 (Windows NT 5.2)
    • Windows Fundamentals for Legacy PCs (based on Windows XP)
    • Windows Vista (Windows NT 6.0)
    • Windows Azure (Cloud OS Platform) 2009
    • Windows Home Server (based on Windows Server 2003)
    • Windows Server 2008 (based on Windows Vista)
    • Windows 7 (Windows NT 6.1)
    • Windows Server 2008 R2 (based on Windows 7)
    • Windows Home Server 2011 (based on Windows Server 2008 R2)
    • Windows Server 2012 (based on Windows 8)
    • Windows 8 (Windows NT 6.2)
    • Windows Phone 8
    • Windows 8.1 (Windows NT 6.3)
    • Windows Server 2012 R2 (based on Windows 8.1)
    • Xbox One system software
    • Windows Phone 8.1
    • Windows 10 (Windows NT 10.0)
    • Windows 10 Mobile
    • Windows Server 2016
  • Windows CE (OS for handhelds, embedded devices, and real-time applications that is similar to other versions of Windows)
    • Windows CE 3.0
    • Windows CE 5.0
    • Windows CE 6.0
    • Windows Mobile (based on Windows CE, but for a smaller form factor)
    • Windows Phone 7
  • Singularity – A research operating system written mostly in managed code (C#)
  • Midori – A managed code operating system
  • Xbox 360 system software
  • Xbox One system software

Timeline of DOS Operating Systems

First end-user releases of IBM–Microsoft-compatible versions









Chapter 7: Storage


  1. Differentiate between storage and memory
  2. Identify various types of storage media and storage devices
  3. Explain how a floppy disk stores data
  4. Identify the advantages of using high-capacity disks
  5. Describe how a hard disk organizes data
  6. Identify the advantages of using an Internet hard drive
  7. Explain how a compact disc stores data
  8. Understand how to care for a compact disc
  9. Differentiate between CD-ROMs, CD-RWs, and DVD-ROMs
  10. Identify the uses of tape
  11. Understand how an enterprise storage system works
  12. Explain how to use PC cards and other miniature storage media
  13. Identify uses of microfilm and microfiche

This chapter explains various storage media and storage devices. Students discover how memory is different from storage. Floppy disks are introduced, and characteristics of a floppy disk, floppy disk drives, care of floppy disks, and high-capacity floppy disks are presented. Hard disks are explained, and students find out about characteristics of a hard disk, how a hard disk works, removable hard disks, hard disk controllers, RAID, and maintaining data on a hard disk. Compact discs, including CD-ROMs and DVD-ROMs, are described. Finally, students learn about tapes, PC Cards, and other types of storage such as smart cards, microfilm and microfiche.

1 | Differentiate Between Storage And Memory

Memory, which is composed of one or more chips on the motherboard, is a temporary holding place for data and instructions during processing. The contents of volatile memory, such as RAM, are lost when the power to the computer is turned off. The contents of nonvolatile memory, such as ROM, are not lost when power is removed from the computer. Storage holds items such as data, instructions, and information for future use; that is, storage holds these items while they are not being processed. Storage is nonvolatile, which means the items in storage are retained even when power is removed from the computer. Compared to memory, the access time (the time it takes to locate a single item) for storage is slow.

2 | Identify Various Types Of Storage Media And Storage Devices

A storage medium (media is the plural) is the physical material on which items are kept. A storage device is the computer hardware that records and retrieves items to and from a storage medium. Storage devices can function as sources of input and output. When storage devices transfer items from a storage medium into memory – a process called reading – they function as sources of input. When storage devices transfer items from memory to a storage medium – a process called writing – they function as sources of output. Types of storage media include floppy disks, hard disks, compact discs, tape, PC Cards, microfilm, and microfiche.

3 | Explain How A Floppy Disk Stores Data

A floppy disk is a portable, inexpensive storage medium that consists of a thin, circular, flexible plastic disk with a magnetic coating enclosed in a square-shaped plastic shell. A floppy disk drive (FDD) is a device that can read from and write on a floppy disk. When you insert a floppy disk into a floppy disk drive, a shutter on the disk’s plastic shell slides to the side to expose the disk’s recording surface. A floppy disk is a type of magnetic media because it uses magnetic patterns to store items. Data is stored in tracks and sectors. A track is a narrow recording band that forms a full circle on the surface of the disk. The disk’s storage locations consist of pie-shaped sections, which break the track into small arcs called sectors. For reading and writing purposes, sectors are grouped into clusters. A cluster consists of two to eight sectors and is the smallest unit of space used to store data. Formatting is the process of preparing a disk for reading and writing.

4 | Identify The Advantages Of Using High-Capacity Disks

A high-capacity disk drive is a disk drive that uses disks with capacities of 100 MB and greater (remember, a typical floppy disk can store only up to 1.44 MB). High-capacity disks are used to store large graphics, audio, or video files and for backup. A backup is a duplicate of a file, program, or disk that can be used if the original is lost, damaged, or destroyed. Three high-capacity disk drives are the SuperDisk™ drive, the HiFD™ drive, and the Zip® drive. The SuperDisk™ drive reads from and writes on a 120 MB or 250 MB SuperDisk™. The HiFD™ (High-Capacity FD) drive reads from and writes on a 200 MB HiFD™ disk. The Zip® drive is a high-capacity disk drive that uses a Zip® disk. The Zip® disk is larger and thicker than a 3.5-inch floppy disk and can store 100 MB or 250 MB of data.

5 | Describe How A Hard Disk Organizes Data

A hard disk, or hard disk drive, consists of several inflexible, circular platters that store items electronically. A platter in a hard disk is made of aluminum, glass, or ceramic and is coated with a material that allows items to be recorded magnetically on its surface. Each platter has two read/write heads, one for each side. Because of the stacked arrangement of the platters, the location of the read/write heads often is referred to by its cylinder, which is the location of a single track through all platters. Some computers improve hard disk access time by using a disk cache, which is a portion of memory that the processor uses to store frequently accessed items. A hard disk can be divided into separate areas, called partitions, each of which functions as if it were a separate hard disk drive.

6 | Identify The Advantages Of Using An Internet Hard Drive

An Internet hard drive is a service on the Web that provides storage to computer users. People use Internet hard drives to:

Eliminate the need to transport files when away from a desktop computer
Instantaneously save large audio, video, and graphics files when surfing the Web
Make audio files, video clips, or pictures available to family, friends, co-workers, and customers
Immediately view time-critical data and images while away from a main office or location
Store offsite backups of data

7 | Explain How A Compact Disc Stores Data

A compact disc (CD) is a flat, round, portable metal storage medium that usually is 4.75 inches in diameter and less than one-twentieth of an inch thick. Compact discs store items using microscopic pits (indentations) and land (flat areas) that are in the middle layer of the disc. A high-powered laser light creates the pits in a single track, divided into evenly spaced sectors, that spirals from the center to the edge of the disc. A low-powered laser reads items by reflecting light off the disc surface. The reflected light is converted into a series of bits that the computer can process.

8 | Understand How To Care For A Compact Disc

With proper care, a compact disc is guaranteed to last five years, but could last up to 50 years. Compact discs should not be stacked or exposed to excessive heat, cold, sunlight, or contaminants. A compact disc should be held by its edges (do not touch the underside of the disc) and placed in its protective case, called a jewel box, when it is not being used. You can clean the bottom surface with a soft cloth and warm water or a specialized CD cleaning kit, and you can repair scratches on the bottom surface with a specialized compact disc repair kit.

9 | Differentiate Between CD-ROMs, CD-RWs, And DVD-ROMs

A CD-ROM, or compact disc read-only memory, is a compact disc that uses the same laser technology as audio CDs. For a computer to read items stored on a CD-ROM, you insert the disc into a CD-ROM drive or CD-ROM player. When viewing animation or video, the speed of a CD-ROM drive, or data transfer rate, is important. A higher the data transfer rate, results in smoother playback of images and sounds.

Most standard CDs are single-session because manufacturers record (write) all items to the disc at one time. Variations of standard CD-ROMs, such as PhotoCD, CD-R (compact disc-recordable), and CD-RW (compact disc-rewritable), are multisession, which means additional data, instructions, and information can be written at a later time. A PhotoCD is a compact disc that contains digital photographic images. A CD-R (compact disc-recordable) is a multisession compact disc onto which you can record your own items. A CD-RW (compact disc-rewritable) is an erasable disc you can write on multiple times.

A DVD-ROM (digital video disc-ROM) is an extremely high-capacity compact disc capable of storing from 4.7 GB to 17 GB. In order to read a DVD-ROM, you must have a DVD-ROM drive. You also can obtain recordable and rewritable versions of DVD. A DVD-R (DVD-recordable) allows you to write on it once and read (play) it many times. With the new rewritable DVD, called a DVD+RW, you can erase and record on the disc multiple times.

10 | Identify The Uses Of Tape

Tape, one of the first storage media used with mainframe computers, is a magnetically-coated ribbon of plastic capable of storing large amounts of data and information at low cost. Because it requires sequential access, or consecutive reading and writing of data, tape is used for long-term storage and backup. (Floppy disks, hard disks, and compact discs all use direct access, which means you can locate a data item immediately, without having to move through all the items stored in front of it.)

11 | Understand How An Enterprise Storage System Works

An enterprise storage system is a strategy that focuses on the availability, protection, organization, and backup of storage in a company. To implement an enterprise storage system, a company uses a combination of techniques. A server stores items needed by users on a network. A RAID system ensures that data is not lost. A tape library is a high-capacity tape system that works with multiple tape cartridges for storing backups of data, information, and instructions. A CD-ROM jukebox holds hundreds of CD-ROMs that can contain application programs and data. An Internet backup can store data, information, and instructions on the Web. A network attached storage (NAC) is an easy way to add hard disk space to a network. A storage area network (SAN) is a high-speed network that connects storage devices.

12 | Explain How To Use PC Cards And Other Miniature Storage Media

A PC Card is a thin, credit card-sized device that fits into a PC Card slot on a notebook or personal computer. PC Cards are used to add storage, memory, communications, and sound capabilities. A smart card stores data on a thin microprocessor embedded in a card similar in size to an ATM card. Two types of smart cards exist: intelligent and memory. An intelligent smart card contains a processor and has input, process, output, and storage capabilities. A memory card has only storage capabilities.

13 | Identify Uses Of Microfilm And Microfiche

Microfilm and microfiche store microscopic images of documents on roll or sheet film. Microfilm uses a 100- to 215-foot roll of film. Microfiche uses a small sheet of film, usually about four inches by six inches. Libraries and large organizations use microfilm and microfiche to archive relatively inactive documents and files.

Expand Your Knowledge

  1. Memory vs. storage
  2. Storage media and devices
  3. Floppy disks
  4. High-capacity disks
  5. Hard disks
  6. Advantages of an Internet Hard Drive
  7. Compact discs
  8. Caring for compact discs
  9. CD-ROMs, CD-RWs, and DVD-ROM
  10. Tape
  11. Enterprise storage systems
  12. PC cards and miniature storage media
  13. Microfilm and microfiche

Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.

1 | Memory Vs. Storage

In general, memory (RAM) is fast, short-term, and volatile. Storage, on the other hand, is slower, long-term, and nonvolatile. Like nonvolatile memory, the contents of storage are retained when a computer’s power is turned off. Unlike most nonvolatile memory, however, the contents of storage usually can be erased or changed.

2 | Storage Media And Devices

The first computer storage medium was a punched card. Herman Hollerith’s punched card tabulating machine helped complete the 1890 census in just 2½ years (compared to 8 years for the 1880 census) at a savings of more than $5 million. Hollerith later founded the Tabulating Machine Company, which eventually became known as International Business Machines (IBM). An understanding of storage terms is very important for purchasers, and users, of storage devices.

  • 1 Kilobyte (KB) ≈ 1 thousand bytes
  • 1 Megabyte (MB) ≈ 1 million bytes
  • 1 Gigabyte (GB) ≈ 1 billion bytes
  • 1 Terabyte (TB) ≈ 1 trillion bytes
  • 1 Petabyte (PB) ≈ 1 quadrillion bytes

1 KB stores approximately ½ page of text. Depending on speed and size, rough costs for RAM are about $40 to $50 per megabyte, while hard disk storage costs are around $0.20 per megabyte.

3 | Floppy Disks

Although the 5.25-inch floppy disk is physically larger, the storage capacity for a 5.25-inch floppy disk is less than for a comparable 3.5-inch floppy disk. Because of the 3.5-inch floppy disk’s greater durability and superior storage capacity, the 5.25-inch floppy disk at best can be considered a very endangered species. With its rigid plastic shell, it may be difficult to see the 3.5-inch disk as “floppy.” The name is justified, however, by the disk’s ancestry and the fact that, if the protective shell is removed, the disk on which the data is written is indeed floppy. Today, most new computers (although not the new Apple iMac) come with a 3.5-inch floppy disk drive; a few manufacturers still will, for a price, add a 5.25-inch floppy disk drive.

The procedure for formatting a floppy disk depends on the operating system. Floppy disks are soft-sectored, meaning that the number of sectors is not predetermined. The cluster concept creates an odd situation: one file with 100,000 bytes requires less disk space (about 25 clusters at 8 sectors per cluster and 512 bytes per sector) than 1,000 small files of 100 bytes each (1,000 clusters).

A floppy disk spins at about 300 revolutions per minute. When writing data, the floppy disk drive’s read/write head generates electronic impulses that change the magnetic polarity of areas along a track to represent the 1 or 0 bits being recorded. When reading data, the read/write head senses the magnetic areas that have been recorded.

4 | High-Capacity Disks

The three types of high-capacity disks were developed by three different manufacturers: SuperDisk™ is from Imation, HiFD™ is from Sony Electronics, Inc, and the Zip® drive is from Iomega.

Although manufacturers always are concerned about software piracy (unlawfully duplicating or distributing proprietary software), many recommend that users create a backup of programs before installing them on a computer. Backup guards against system failures, such as a head crash, and human errors, such as inadvertently deleting key files. If you ever accidentally delete a file, seek help immediately from a computer support person who sometimes can recover the “erased” file.

5 | Hard Disks

In the early 1980s, hard disk drives were called “Winchester” drives because they had two 30-megabyte disks, a characteristic reminiscent of the Winchester 30-30 rifle. In addition to making hard disks more efficient and allowing the installation of multiple operating systems, large hard disks may be partitioned to:

  • Limit software disasters (which usually are confined to one partition)
  • Shorten path lengths and assist in file keeping
  • Save keystrokes (operating systems usually return to the directory they left)
  • Enhance security (different partitions may warrant different safety levels)
  • Permit variable frequencies of backup
  • Allow unattended backups (smaller partitions may fit on a single tape)

Unlike floppy disk read/write heads, hard disk read/write heads do not touch the disk surface. Because of the close tolerance between the disk head and the rotating disk surface, hard disk drives are manufactured in an extremely clean setting, typically cleaner than a hospital operating room. Many hard disk drives are warranted for five years, but most warranties are prorated, meaning that if it fails in the first year it can be replaced at 20 percent of the original cost. All warranties are void, however, if the drive is opened, because contaminated air and dust render the drive unusable.

On a personal computer, a hard disk controller (HDC) is the interface for the hard disk. Many external hard drives use a USB port as their interface. Two other types of HDCs are the EIDE (Enhanced Integrated Drive Electronics) controller, which can support up to four hard disks, and SCSI (small computer system interface) controllers, which can support multiple disk drives as well as other peripherals. A removable hard disk is a disk drive in which a plastic or metal case surrounds the hard disk so that you can remove it from the drive. Two reasonably priced, removable hard disks are the Jaz® disk, which can store up to 2 GB, and the Peerless™ disk, which can store up to 20 GB.

A RAID (redundant array of independent disks) system integrates two or more hard disks, duplicating data, instructions, and information to improve data reliability.

6 | Advantages Of An Internet Hard Drive

When your computer’s hard disk is full, an Internet hard drive can provide additional storage space. Ease of use, number of features, and amount of storage space varies, based on the specific Internet hard drive Web site. Do you trust the security of online storage services? What types of information might you store online? What are other advantages and disadvantages of Internet hard drives?

7 | Compact Discs

Laser disks first were developed by RCA for showing home movies. The 14-inch optical disk was a derivative of these early 1980s video disks. Advantages that compact discs offer over hard disks include: greater data density, less expense (bit for bit), increased durability, and no head crashing.

8 | Caring For Compact Discs

Compare the proper care guidelines for using floppy disks (page 7.9) with the proper care guidelines for using compact discs (page 7.19). How are the guidelines similar? How are they different?

9 | CD-ROMs, CD-RWs, And DVD-ROM

On a computer, screen displays for software used to play audio CDs resemble typical CD players, but the controls are accessed with a pointing device. A single CD-ROM can store the entire Encyclopedia Britannica with room left over. You write on a CD-R using a CD recorder or a CD-R drive and special software. To write on a CD-RW disc, you must have CD-RW software and a CD-RW drive. A multiread CD-ROM drive can read audio CDs, data CDs, CD-Rs, and CD-RWs.

On one side, a DVD-ROM can store up to 13 times the amount of information that can be stored on a CD-ROM. Double-sided DVD-ROMs (DVD-ROMs that store data on both sides), can store up to 26 times the amount of information stored on a CD-ROM.

A DVD+RW is similar to a CD-RW, except it has storage capacities up to 4.7 GB. To write on DVD+RW discs, you must have a DVD writer.

Along with processor speed, amount of memory, and hard disk capacity, CD-ROM drive speed is a featured element of almost every personal computer advertisement. Like CD-ROM drives, DVD-ROM drive speeds are indicated with the letter X to represent the standard speed of a DVD drive. That speed, however, is considerably faster than the data transfer rate of the original CD-ROM. While a 24X CD-ROM drive has a data transfer rate of 3,600 KB per second, a 5X DVD-ROM has a data transfer rate of 6,750 KB per second.

10 | Tape

Magnetic tape was developed in the mid-1950s to replace the earlier method of storing data on punched cards. To better understand the difference between sequential access and direct access (or random access), compare an audio cassette tape to a CD-ROM. An audio cassette tape is sequential; to listen to the fourth song it is necessary to listen to (or fast-forward through) the first three songs. A CD is direct; it is possible to go straight to the fourth song. For what applications would sequential storage be appropriate? For what applications would it be unsuitable? Tape cartridges can be purchased formatted or unformatted. One-quarter-inch wide cartridge tapes typically are 600 feet long. Unattended tape backup is a great time saver. Consider how many 1.44 MB floppy disks are needed and how much time is required (removing disks as they become full and inserting new disks) to back up 150 MB of data. With tape backup, you can press a key, go about other business, and return to remove the finished backup tape.

11 | Enterprise Storage Systems

Large business users often utilize an enterprise storage system strategy. Why? What makes an enterprise storage system strategy attractive to large business users?

12 | PC Cards And Miniature Storage Media

Smart cards can hold the equivalent of 30 typewritten pages of data and cost from $5 to $50. Smart card readers are about $100. As a storage media for an individual’s medical history, smart cards offer obvious benefits. The cards can be carried in a wallet with, or in lieu of, an insurance card, providing both insurance records and an immediate, up-to-date medical history. A form of smart cards, called Personal Information Carriers (PICs) is being adopted by the army to replace dog tags. Think of other ways that smart cards and electronic money (e-money) could be used. Will digital cash someday replace conventional currency? Why or why not?

13 | Microfilm And Microfiche

Microfilm and microfiche images are so small that they can be read only with a microfilm and microfiche reader. Large organizations use microfilm and microfiche to archive inactive files.


Chapter 6: Output


  1. Define the four categories of output
  2. Identify the different types of display devices
  3. Describe factors that affect the quality of a display device
  4. Identify monitor ergonomic issues
  5. Explain the differences among various types of printers
  6. Describe the uses of speakers and headsets
  7. Identify the purpose of data projectors, fax machines, and multifunction devices
  8. Explain how a terminal is both an input and output device
  9. Identify output options for physically challenged users

In this chapter, you learn what is output and what are output devices. Display devices are introduced, including CRT monitors, flat-panel displays, video cards, and high-definition television. You explore monitor quality and monitor ergonomics. Various types of printers are presented, such as impact printers, nonimpact printers, portable printers, plotters and large-format printers, and special-purpose printers. You find out about audio output and other output devices, including data projectors, facsimile machines, and multifunction devices. Finally, you become acquainted with terminals and output devices for physically challenged users.

1 | Define The Four Categories Of Output

Output is data that has been processed into a useful form called information. Four types of output are text, graphics, audio, and video. Text consists of characters (letters, numbers, punctuation marks, or any other symbol requiring one byte of computer storage space) that are used to create words, sentences, and paragraphs. Graphics are digital representations of nontext information such as drawings, charts, photographs, and animation (a series of still images in rapid sequence that gives the illusion of motion). Audio is music, speech, or any other sound. Video consists of images played back at speeds to provide the appearance of full motion. An output device is any computer component capable of conveying information to a user.

2 | Identify The Different Types Of Display Devices

A display device is an output device that visually conveys text, graphics, and video information. Information shown on a display device is called soft copy because the information exists electronically and is displayed for a temporary period of time. Display devices include CRT monitors, LCD monitors and displays, gas plasma monitors, and televisions. A CRT monitor is a monitor that is similar to a standard television set because it contains a cathode ray tube. A cathode ray tube (CRT) is a large, sealed, glass tube. The front of the tube is a screen coated with phosphor material that glows as an electron beam moves back and forth, which produces an image on the screen. LCD monitors and LCD displays use liquid crystal to present information on the screen. A liquid crystal display (LCD) has liquid crystals between two sheets of material. When an electric current passes through the crystals, they twist, causing some light waves to be blocked and allowing others to pass through, which creates the images.

Similar to an LCD display, a gas plasma monitor is a flat-panel display. A gas plasma monitor, however, substitutes a layer of gas for the liquid crystal material. When voltage is applied, the gas releases ultraviolet light that causes pixels on the screen to glow and form an image. An NTSC converter converts a computer’s digital signal into an analog signal that a standard television set can display. High-definition television (HDTV) is a type of television set that works with digital broadcasting signals and supports a wider screen and higher resolution than a standard television set.

3 | Describe Factors That Affect The Quality Of A Display Device

The quality of a CRT monitor depends largely on its resolution, dot pitch, and refresh rate. The quality of an LCD monitor or display depends primarily on its resolution.

A CRT monitor’s screen is coated with tiny dots of phosphor material, called pixels, that glow when electrically charged to produce an image. Resolution, which describes the sharpness and clearness of that image, is related directly to the number of pixels a monitor can display. The greater the number of pixels the display uses, the better the quality of the image. Dot pitch, a measure of image clarity, is the distance between each pixel on a display. The smaller the distance between pixels (dot pitch), the sharper the image. Refresh rate is the speed that a monitor redraws images on the screen. Refresh rate should be fast enough to maintain a constant, flicker-free image.

The resolution of an LCD monitor or display generally is proportional to the size of the monitor or display. That is, the resolution increases for larger monitors and devices.

4 | Identify Monitor Ergonomic Issues

The goal of ergonomics is to incorporate comfort, efficiency, and safety into the design of items in the workplace. Features that address monitor ergonomic issues include controls to adjust the brightness, contrast, positioning, and height and width of images. Newer monitors have digital controls that allow you to fine-tune the display. Many monitors also have a tilt and swivel base so the angle of the screen can be altered to minimize neck strain and glare. Monitors produce a small amount of electromagnetic radiation (EMR), which is a magnetic field that travels at the speed of light. High-quality monitors should comply with MPR II, a standard that defines acceptable levels of EMR for a monitor.

5 | Explain The Differences Among Various Types Of Printers

A printer is an output device that produces text and graphics on a physical medium such as paper or transparency film. Printed information is called hard copy because the information exists physically and is a more permanent from of output. Printers can be grouped in two categories: impact and nonimpact.

Impact printers form characters and graphics by striking a mechanism against an ink ribbon that physically contacts the paper. A dot-matrix printer is an impact printer that prints images when tiny wire pins on a print head mechanism strike an inked ribbon. A line printer is an impact printer that prints an entire line at one time. Two popular types of line printers are band printers and shuttle-matrix printers.

Nonimpact printers form characters and graphics without actually striking the paper. An ink-jet printer is a nonimpact printer that sprays drops of ink onto a piece of paper. A laser printer is a nonimpact printer that creates images using a laser beam and powdered ink, called toner. A thermal printer is a nonimpact printer that generates images by pushing electrically heated pins against heat-sensitive paper. Although the print quality of standard thermal printers generally is low, two special types of thermal printers, thermal wax-transfer printers and dye-sublimation printers, have a much higher print quality.

Some printers are used for special purposes. A photo printer is a color printer that can produce photo lab quality pictures as well as printing everyday documents. A label printer is a small printer that prints on an adhesive type material that can be placed on a variety of items. A portable printer is a small, lightweight printer that allows a mobile user to print from a notebook or handheld computer while traveling. Plotters are sophisticated printers used to produce high-quality drawings such as blueprints, maps, and circuit diagrams. A large-format printer, which operates like an ink-jet printer but on a larger scale, creates photo-realistic quality color prints.

6 | Describe The Uses Of Speakers And Headsets

An audio output device produces music, speech, or other sounds. Two commonly used audio output devices are speakers and headsets. Most personal computers have an internal speaker that outputs low-quality sound. Many users add high-quality stereo speakers or purchase PCs with larger speakers built into the sides of the monitor. A woofer can be added to boost low bass sounds. A headset plugged into a port on the sound card allows only the user to hear sound from the computer.

7 | Identify The Purpose Of Data Projectors, Fax Machines, And Multifunction Devices

A data projector takes the image on a computer screen and projects it onto a large screen so that an audience of people can see the image. Two smaller, lower priced data projectors are an LCD projector, which uses liquid crystal display technology, and a digital light processing (DLP) projector, which uses tiny mirrors. A facsimile (fax) machine transmits and receives documents over telephone lines. A fax modem is a communication device that allows you to send (and sometimes receive) electronic documents as faxes. A multifunction device (MFD) is a single piece of equipment that looks like a copy machine but provides the functionality of a printer, scanner, copy machine, and sometimes a fax machine.

8 | Explain How A Terminal Is Both An Input And Output Device

A terminal is a device that performs both input and output because it consists of a keyboard (input), a monitor (output), and a video card. A dumb terminal has no processing power and cannot function as an independent device. Dumb terminals connect to a host computer that performs the processing and then sends the output back to the dumb terminal. An intelligent terminal has memory and a processor that has the capability of performing some functions independent of the host computer. Some special-purpose terminals perform specific tasks and contain features designed for a particular industry. A point-of-sale (POS) terminal is a special-purpose terminal used to record purchases at the point where a consumer buys a product or service. An automatic teller machine (ATM) is a self-service, special-purpose terminal used to access your bank account.

9 | Identify Output Options For Physically Challenged Users

For users with mobility, hearing, or vision disabilities, many different types of output devices are available. For example, hearing-impaired users can instruct programs to display words instead of sound. With the Windows operating system, physically challenged users can set options to make programs easier to use. Visually impaired users can change the size or color of text to make words easier to read. Blind users can use speech output, where the computer reads information that displays on the screen. A Braille printer outputs information in Braille onto paper.

Expand Your Knowledge

  1. Output
  2. Display devices
  3. Monitor quality
  4. Monitor ergonomics
  5. Printers
  6. Audio output
  7. Other output devices
  8. Terminals
  9. Output devices for physically challenged users

Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.

1 | Output

For computer users, output may be the most significant stage of the information processing cycle. Output is the goal of input and processing. It provides the information users need to work and make decisions. Output used by a machine often is an intermediate result. Eventually it will be processed into a form that can be used by people.

Sound Blaster is the de facto standard for computer audio. You may be familiar with audio output from certain cars and vending machines: “Fasten seat belts” or “Please deposit twenty-five cents.” Voice output telephone calls promoting banks, services, or political candidates are increasingly common. Yet, audio output is not always welcome. Voice output once was employed in grocery store checkouts. Because of negative public reaction, however, it has been discontinued.

2 | Display Devices

Although “soft” implies a touchable quality, soft copy only has an electronic, intangible existence, unlike the physical presence of hard copy (printed material).

So much information today is in color that sales of monochrome monitors have plummeted. A number of less expensive monitors that use gray scaling, however, are popular among business users.

The CRT in a monitor uses from 15,000 to 20,000 volts to accelerate electrons from the gun to the screen. Servicing of monitors, therefore, only should be done by trained personnel. Color monitors sometimes are known as RGB monitors (for red, green, and blue). Red, green, and blue are light’s primary colors. These three fundamental colors are not the same as the three primary pigments you may have mixed in art class (red, yellow, and blue). Believe it or not, when red light and green light mix the result is seen as yellow light.

Application software sometimes requires a specific video standard for optimal performance. A factor to keep in mind when purchasing a monitor is that any video card capable of a higher resolution can run programs that require lower resolution levels – a concept called backward compatibility. The CGA standard monitor, introduced in 1981, had a 640 x 200 resolution and displayed four colors. Today’s SVGA monitor has a resolution more than 6 times better and can display 16.7 million colors. Although flat-panel displays use relatively little power and the clarity of the images they produce continues to improve, they are not as bright as CRT monitors. Because active matrix displays are much clearer than passive matrix displays, most of today’s notebook computers have active matrix displays. LCD screens often are backlighted but consume microwatts of power and give off virtually no heat. Gas plasma screens, while much brighter, consume hundreds or thousands of times more power than LCDs.

3 | Monitor Quality

In some ways, pixel images on a monitor are similar to the works created by pointillist painters like Georges Seurat.

The flickering that is seen on some monitors is a result of a too-slow refresh rate. Older monitors refresh images using a technique called interlacing, in which the an electron beam draws only half the horizontal lines with each pass. Most of today’s monitors are noninterlaced. For the eyes, noninterlaced monitors tend to be less tiring than interlaced monitors. All video display devices look better in a dark environment.

4 | Monitor Ergonomics

Studies show that working in an ergonomically designed environment lessens fatigue, reduces injury, and increases productivity.

5 |Printers

Varying requirements have led to the development of printers with different capabilities. In addition to the questions posed in Figure 6-15, the following factors should be considered when purchasing any printer:

  • What is the total printer cost? (Supplies and maintenance should be weighed along with initial price.)
  • How much is the printer used? (The duty cycle, or recommended maximum output per month, and the mean time between failure (MTBF), or estimated time before a component needs service, are key considerations.)
  • What type of output will be produced? (A printer’s capabilities must match output requirements.)
  • Who will use the output? (External correspondence requires better quality printing than internal-only reports.)
  • Are multiple copies necessary? (Only impact printers can produce multiple copies on a single pass.)
  • Is color required? (Color significantly adds to the cost of some printers.)
  • Where will the printer be used? (Impact printers are noisy in closed locations, but are more resistant to extreme conditions.)
  • For a printer to function, the appropriate printer driver must be installed in the computer. Drivers are software that transform the computer’s output into signals a printer can understand and use. Most printer manufacturers include driver software. Because most printers are 1,000 times slower than computers, all printers have a buffer that temporarily stores a few pages, allowing the computer to dump output into the buffer and continue processing.

Print quality depends on dots per inch and the amount of overlap. Letter quality (LQ) print corresponds to that produced by a typewriter. Many impact printers produce near letter quality (NLQ) print, which is slightly less clear than letter quality. Although most dot-matrix printers use continuous-form paper (in which individual sheets are connected together), some also can use single-sheet paper without removing any paper by “parking” continuous-form paper while a single sheet is printed.

Nonimpact printers represent the fastest growing segment of the printer market. One attraction of nonimpact printers is their quiet operation. Imagine the noise level in an office with several impact printers operating simultaneously! Due to separate development, printer resolution is expressed in dots per inch while monitor resolution is stated in pixels per inch (which is dependent on dot pitch). The resolution of a high-end printer is about 10 times better than the resolution of an SVGA monitor. Although high resolution is good, more dpi requires additional memory.

Unlike other types of nonimpact printers, the image produced by ink-jet printers can smear if moistened. Although laser printers are popular, they do not handle all printing jobs well. Special feeders are needed to print multiple envelopes, and multipart forms cannot be used at all.

6 | Audio Output

Like other computer components, high-quality speakers are growing smaller. NXT has developed speakers for its flat-panel technology that deliver superior sound despite being only one sixty-fourth of an inch thick. The speaker technology has been licensed by NEC, Acer, and Mission and is included in their new PCs and notebooks.

7 | Other Output Devices

Data projectors are particularly useful when demonstrating computer software packages. A data projector, along with the modem-equipped notebook computer and portable printer, is part of the arsenal of business travelers. With these weapons, the “road warrior” can create, transmit, receive, and project sales presentations.

Which device – a stand-alone fax machine or a fax modem – would be most useful for a home user. For a small office? For a large office? Why?
Under what circumstances might you consider purchasing an MFD. Why?
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8 | Terminals

Terminals also sometimes are called display terminals or video display terminals (VDTs). Historically, terminals have been dumb and dependent on a mainframe, to which they were connected by a cable, called an umbilical cord, for any processing. The advent of inexpensive personal computers gave rise to terminals with independent processing capabilities. Personal computers that function as intelligent terminals are connected to switch boxes that allow them to operate as PCs or to access a mainframe. Although they are intelligent terminals, some workstations are designed without disk drives so restricted data cannot be downloaded or copied. Some terminals, such as credit card authorization devices in department stores, look very little like normal computers. POS (point-of-sale) terminal printers are special-purpose printers used at supermarket checkouts. These usually are low-grade dot-matrix printers that have seven or nine pins.

9 | Output Devices For Physically Challenged Users

If, when using Windows, the Accessibility command does not appear on the Accessories submenu, you may have to install Accessibility Options. To install Accessibility Options, open the Add/Remove Programs Properties dialog box at the Windows Setup tab by clicking Start, pointing to Settings, clicking Control Panel, double-clicking Add/Remove Programs, and then clicking the Windows Setup tab. If you used a CD to install Windows, you will be prompted to insert it into your computer. Under Components, click to select the Accessibility Options check box and then click OK.

In Windows, the Accessibility Properties dialog box can be used to change both input and output options for physically challenged users. To open the Accessibility Properties dialog box, click the Start button, point to Settings, click Control Panel on the Settings submenu, and then double-click the Accessibility Options icon in the Control Panel dialog box. The Accessibility Properties dialog box can be used to change:

  • Keyboard options – StickyKeys (allows the SHIFT, >alt, and CTRL keys, which usually are used with other keys, to be used by pressing one key at a time), FilterKeys (ignores brief or repeated keystrokes), and ToggleKeys (plays a tone when a toggle key is pressed)
  • Sound options – SoundSentry (generates visual warnings when a sound is made) and ShowSounds (displays captions for program speech and sound)
  • Display options – High Contrast (uses colors and fonts designed for easy reading)
  • Mouse options – MouseKeys (allows pointer to be controlled with the numeric keypad)


Chapter 5: Input


  1. Describe the two types of input
  2. List the characteristics of a keyboard
  3. Identify various types of keyboards
  4. Identify various types of pointing devices
  5. Explain how a mouse works
  6. Describe different mouse types
  7. Explain how voice recognition works
  8. Understand how to input data into a handheld computer
  9. Identify the uses of a digital camera
  10. Describe the various techniques used for video input
  11. Describe the uses of PC video cameras and web cams
  12. Explain how scanners and other reading devices work
  13. Identify alternative input devices for physically challenged users

In this chapter, you learn what is input and what are input devices. The keyboard is presented and different keyboard types are described. You are introduced to various pointing devices, such as the mouse, trackball, touchpad, pointing stick, joystick, touchscreen, and pen input. Scanners and reading devices, including optical scanners, optical readers, magnetic ink character recognition readers, and data collection devices are explained. You learn about digital cameras, audio input, speech recognition, video input, and videoconferencing. Finally, input devices for physically challenged users are explored.

1 | Describe The Two Types Of Input

Input is any data or instructions entered into the memory of a computer. Two types of input are data and instructions. Data is a collection of unorganized items that can include words, numbers, pictures, sounds, and video. A computer processes data into information, which is organized, meaningful, and useful. Instructions can be in the form of programs, commands, or user responses. A program is a series of instructions that tells a computer how to perform the tasks necessary to process data into information. A command is an instruction given to a computer program. A user response is an instruction you issue to the computer by responding to a question posed by a computer program. Any hardware component that allows you to enter data, programs, commands, and user responses into a computer is an input device.

2 | List The Characteristics Of A Keyboard

The keyboard is an input device that contains keys you press to enter data into a computer. Desktop computer keyboards usually have from 101 to 105 keys, while keyboards for smaller computers contain fewer keys. All keyboards have a typing area used to type letters of the alphabet, numbers, punctuation marks, and other basic characters. Many desktop computer keyboards also have a numeric keypad designed to make it easier to enter numbers, function keys programmed to issue commands and accomplish certain tasks, arrow keys used to move the insertion point (a symbol on the screen that indicates where the next typed character will display), and toggle keys that can be switched between two different states.

3 | Identify Various Types Of Keyboards

A standard computer keyboard sometimes is called a QWERTY keyboard because of the layout of its typing area. An enhanced keyboard has 12 function keys along the top row, 2 ctrl keys, 2 alt keys, and a set of arrow and additional keys between the typing area and the numeric keypad. Cordless keyboards transmit data via infrared light waves. Keyboards for notebook and handheld computers usually have smaller and fewer keys than desktop computers. A portable keyboard is a full-sized keyboard you can attach to and remove from a handheld computer. Some manufacturers have designed ergonomic keyboards to reduce the chance of workplace injuries. The goal of ergonomics is to incorporate comfort, efficiency, and safety into the design of workplace items.

4 | Identify Various Types Of Pointing Devices

In a graphical user interface, the pointer is a small symbol on the screen. A pointing device is an input device that allows you to control the pointer. Common pointing devices include the mouse, trackball, touchpad, pointing stick, joystick, touch screen, light pen, and a stylus. A mouse is a pointing device, designed to fit comfortably under the palm of your hand, that is moved across a flat surface. A trackball is a stationary pointing device with a ball mechanism on its top. A touchpad is a flat, rectangular pointing device that is sensitive to pressure and motion. A pointing-stick is a pressure-sensitive pointing device shaped like a pencil eraser that is positioned between keys on the keyboard. A joystick is a vertical lever mounted on a base. A light pen is a handheld device that contains a light source or can detect light. A touch screen is a touch-sensitive display on the screen. A stylus looks like a ballpoint pen but uses pressure, instead of ink, to write text and draw lines. An electronic pen can be used on a graphics tablet, which consists of a flat, rectangular, electronic plastic board used to input graphical data.

5 | Explain How A Mouse Works

As you move a mouse across a flat surface, the movement is translated into signals that are sent to the computer, and the pointer on the screen also moves. When you move the mouse to the right, the pointer moves to the right on the screen. For Windows users, the top of a mouse has at least two buttons and sometimes also a wheel. Generally, you use a mouse to move the pointer on the screen to an object and then press a button, or click, to perform a certain action on that object. Other operations you can perform using a mouse include right-click, double-click, drag, right-drag, rotate wheel, and press wheel button.

6 | Describe Different Mouse Types

A mechanical mouse has a rubber or metal ball on its underside. When the ball rolls in a certain direction, electronic circuits in the mouse translate the movement into signals that are sent to the computer. For better traction, you should place a mechanical mouse on a mouse pad. An optical mouse has no moving parts; instead it uses devices that emit and sense light to detect the mouse’s movement. An optical mouse can be used on nearly all surfaces, is more precise than a mechanical mouse, and does not require cleaning. A cordless mouse, or wireless mouse, is a battery powered device that transmits data using wireless technology, such as radio waves or infrared light waves. A cordless mouse uses technology very similar to that of a cordless keyboard.

7 | Explain How Voice Recognition Works

Voice input is the process of entering data by speaking into a microphone that is attached to the sound card on a computer. Voice recognition is the computer’s capability of distinguishing spoken words. The first voice recognition programs were speaker dependent. With speaker-dependent software, the computer makes a profile of your voice, which means you have to train the computer to recognize your voice. Today, most voice recognition programs use speaker-independent software, which has a built-in set of word patterns and does not have to be trained to recognize your voice. Some voice recognition software requires discrete speech, meaning that you have to speak slowly and separate each word with a short pause. Most voice recognition products, however, support continuous speech, allowing you to speak in a flowing conversational tone.

8 | Understand How To Input Data Into A Handheld Computer

To satisfy the input needs of many different types of users, handheld computers provide many different ways to input data. A handheld computer typically includes a basic stylus. With the stylus, you can enter data using an on-screen keyboard or using handwriting recognition software that translates handwritten letters and characters into symbols the computer understands. Other input alternatives available with some handheld computers include attaching a full-sized keyboard, transferring data from a desktop computer, using voice input, and attaching a digital camera.

9| Identify The Uses Of A Digital Camera

A digital camera is used to take pictures and store the photographed images digitally instead of on traditional film. Pictures are stored on a storage medium, such as a floppy disk, SuperDisk, Clik! disk, PC Card, compact flash card, memory stick, mini-CD, or microdrive. Many digital cameras allow you to review and edit the images while they are in the camera. You also can download, or transfer a copy of, the stored image to a computer. Once on a computer, the pictures can be edited with photo-editing software, printed, faxed, sent via electronic mail, included in another document, or posted to a Web site. There are three basic types of digital cameras. A studio camera is a stationary digital camera used for professional studio work. A field camera is a portable camera, often used by photojournalists, that has many lenses and other attachments. A point-and-shoot camera is more affordable and lightweight and provides acceptable quality photographic images for the home or small business user.

10 | Describe The Various Techniques Used For Video Input

Video input, or video capture, is the process of entering a full-motion recording into a computer and storing the video on a storage medium. Many video devices use analog video signals. To input video from these devices, the device is plugged into a video capture card, an expansion card that converts the analog signal into a digital signal the computer can understand. A digital video (DV) camera is a new generation of video camera that records video as digital signals, instead of using analog signals, and therefore does not require a video capture card. Video files can demand huge amounts of storage space. Video compression reduces the size of video files by recognizing that only a small portion of an image changes from frame to frame. Instead of storing every frame in its entirety, a video compression program might store an initial frame and then store only the changes from one frame to the next. A video decoder is a card that decompresses video. A video digitizer can be used to capture an individual frame from a video and save the still picture in a file.

11 | Describe The Uses Of PC Video Cameras And Web Cams

A PC camera is a DV camera that allows home users to record, edit, capture video and still images, and make video telephone calls on the Internet. During a video telephone call, both parties can see each other as they talk. Although usually placed on top of the monitor and attached to a computer’s USB port, some PC cameras are portable and can be used anywhere. A Web cam is a video camera whose output displays on a Web page. Some Web sites have live Web cams that display still pictures and update the displayed images at specified time intervals.

12 | Explain How Scanners And Other Reading Devices Work

Scanners and optical readers can capture data from a source document, which is the original form of the data. A scanner is a light-sensing input device that reads printed text and graphics and then translates the results into a form a computer can use. One of the more popular scanners is a flatbed scanner, which works similarly to a copy machine except it creates a file of the document in memory instead of a paper copy. Many scanners include OCR software, which converts a scanned image into a text file that can be edited. An optical reader uses a light source to read characters, marks, and codes and converts them into digital data that a computer can process. Three types of optical readers are optical character recognition, optical mark recognition, and bar code scanner. Optical character recognition (OCR) is a technology that reads typewritten, computer printed, or handwritten characters from ordinary documents and translates the images into a form that the computer can understand. Optical mark recognition (OMR) devices read hand-drawn marks such as circles or rectangles. A bar code scanner uses laser beams to read bar codes, which are identification codes consisting of vertical lines and spaces of different widths. Another type of reader, called a magnetic-ink character recognition (MICR) reader, reads text printed with magnetized ink and is used almost exclusively by the banking industry.

13 | Identify Alternative Input Devices For Physically Challenged Users

Whether at work or at home, it may be necessary to obtain input devices that address physical limitations. Voice recognition is ideal for blind or visually impaired users, but several other input devices also are available. A keyguard, which is placed over the keyboard, allows people with limited hand mobility to rest their hands on the keyboard and guides a finger or pointing device so that only one key is pressed. Keyboards with larger keys and on-screen keyboards on which keys are pressed using a pointing device also can help. Pointing devices such as small trackballs controlled with a thumb or one finger and head-mounted pointers also are available for users with motor disabilities. Two new developments are gesture recognition and computerized implant devices. With gesture recognition the computer will be able to detect human motions. Computerized devices implanted in the brain will allow paralyzed individuals to transmit signals to the computer.

Expand Your Knowledge

  1. Input
  2. The keyboard
  3. Keyboard Types
  4. Pointing devices
  5. Using a mouse
  6. Mouse types
  7. Voice recognition
  8. Handheld computer input
  9. Digital cameras
  10. Video input
  11. PC video cameras and web cams
  12. Scanners and reading devices
  13. Input devices for physically challenged users

Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.

1 | Input

Of the four operations in the information processing cycle – input, process, output, and storage – input is the operation to which computer users are most closely linked and on which each subsequent action depends.

Typed commands use keywords – specific words, phrases, or codes that a program recognizes as instructions. Keywords are an essential element of command-driven programs, such as DOS. The problem with keywords is that:

  • they must be memorized, and
  • they must be entered correctly

This makes command-driven programs difficult to use. Menu-driven programs and graphical user interfaces eliminate the problems of having to memorize and correctly type keywords.

2 | The Keyboard

Data entered through the keyboard averages about one error for every 300 characters, while data entered more directly, such as with a scanning device, averages only one error for every 3 million characters. Nevertheless, the keyboard continues to be the most popular input device. Some special keys – ALT, CTRL, and SHIFT – almost always are used in combination with other keys. Desktop computer keyboards generally have two ways to enter numbers – the numeric keypad and the row of number keys above the alphabetic keys. Think of situations in which both would be used. The numeric keypad also contains arrow keys, but these keys are active only when the keypad is turned off. Although the purpose of function keys varies, some developers have tried to standardize certain keys (such as using F1 to access online Help). In addition to the NUM LOCK key, other toggle keys are the CAPS LOCK key and the INSERT key. Unlike the CAPS LOCK key on a typewriter, the CAPS LOCK key on a computer keyboard cannot be used to print the special characters on the keys in the number row.

3 | Keyboard Types

Keyboards are used primarily to enter alphanumeric data. Not surprisingly, keyboards for oriental languages are significantly more complex than the keyboard shown in Figure 5-3. The QWERTY keyboard was devised in 1867 by Christopher Sholes, inventor of the first practical commercial typewriter. Ironically, Sholes’ intent when designing the keyboard was to slow typists down; if typists worked too quickly, keys had a tendency to jam. Many feel the QWERTY keyboard is an anachronism, and its continued use is counterproductive. A more recent design, called the Dvorak keyboard (named for August Dvorak, American educator, 1895-1975) places the most frequently used keys in the middle of the typing area. Studies have shown that trained typists using the Dvorak keyboard are up to 20 times faster than trained QWERTY typists. Despite this, the Dvorak keyboard rarely is used. Repetitive stress injury (RSI) afflicts more than 1.8 million people in the United States. A debilitating repetitive stress injury that plagues some keyboard users is carpal tunnel syndrome. This painful wrist injury affects sufferers not only when working at the keyboard, but when performing other tasks as well. The wrist rest on the keyboard in Figure 5-3 is designed to reduce wrist strain.

4 | Pointing Devices

The original mouse was a one-button, cigarette-pack shaped device invented by Doug Engelbart in 1964. Today, many software manufacturers have made the mouse (or a related pointing device) an essential part of their applications. When the screen is cluttered or pointer targets are small, however, some experienced users still prefer keyboard commands if they are offered.

Some people feel that a touchpad is the most difficult pointing device to use. To satisfy divergent preferences, several laptop computers include both a pointing stick and a touchpad.

Although trackballs, touchpads, and pointing stick devices require less space than a mouse (making them popular for portable computers), most people find them harder to use. Because of this a smaller mouse, called Mouse2Go, has been developed for use on a small pad that clips to the side of a portable computer.

Joystick concepts evolved from actual use in jet fighter airplanes, where joysticks allowed pilots to control an aircraft’s movement quickly and precisely.

Although touch screen users touch a symbol on the screen, it is the location where the touch occurred, not the symbol contacted, that is important. Because they are so user-friendly, even people unfamiliar with computers are comfortable with touch screens.

5 | Using a Mouse

The major advantage of a mouse is that it is easy to use. The disadvantages are twofold: first, the mouse requires additional desk space, making it difficult to use in cramped locations; and second, mouse use demands that a hand be taken from the keyboard (unlike a pointing stick, which can be used without removing a hand from the keyboard). When a mouse has two buttons, one is the primary mouse button and the other is the secondary mouse button. To reverse the functions of these buttons or change other mouse options in Windows 98, point to Settings on the Start menu, click Control Panel on the Settings submenu, then double-click the Mouse icon in the Control Panel window. In the Mouse Properties dialog box that displays, the Basics tab allows you to change pointer speed, button selection, and double-click speed.

6 | Mouse Types

Since its introduction in 1965, the mouse has gone through several transformations. Microsoft’s “green eye” mouse, an early mouse with two buttons, was released in 1983 and now is a collector’s item. Other interesting mouse variations include Spectrum’s RingMouse (which uses infrared to point), Interlink’s wireless mouse (often used for presentations), and Interlink’s DuraPoint PC mouse (an incredibly durable mouse that gained the Pentagon’s interest). A new mouse from Immersion Corporation provides tactile sensations, with an internal motor that allows users to “feel” the desktop. The mouse – which senses cursor position, identifies screen objects, and sends pulses to a motor beneath the surface of the mouse – lets users feel icons, sense Web links, or bump through menu commands.

7 | Voice Recognition

Some experts believe voice input eventually will be the most common way to operate a computer. Speech recognition is particularly welcome to people with certain disabilities. Although speech recognition continues to improve, developers admit that advertisements touting high accuracy rates generally assume a standard vocabulary. Specialized words, regional accents, and local dialects reduce accuracy. Even a 95 percent accuracy rate, meaning that on average 1 out of every 20 words is wrong, may not inspire confidence. (Imagine if, in conversation, every 20th word spoken was misinterpreted.) Nevertheless, voice recognition systems are gaining in popularity.

8 | Handheld Computer Input

Instead of using a keyboard, with most handheld computers you write or make selections on the computer screen with a stylus. Although a handheld computer typically includes a basic stylus, you can buy more elaborate models that have a ballpoint pen at one end and a stylus at the other.

9 | Digital Cameras

Some manufacturers use dots per inch to represent a digital camera’s resolution, or the sharpness and clarity of the image it produces. Dots per inch (DPI) is the number of pixels in an inch of screen display. A pixel is a single point in an electronic image. Digital cameras for the consumer range from 640 x 480 dpi to 1,792 to 1,200 dpi. The actual photographed resolution is called the optical resolution. Some manufacturers also state enhanced resolution, which uses a special formula to add pixels between those generated by the optical resolution. With the price of digital cameras decreasing, will the era of film-based cameras soon come to an end? Why or why not?

10 | Video Input

Video input is used in a variety of ways, from developing training films to creating presentation enhancements. Video input also has been used in the workplace to record (sometimes secretly) office or assembly-line workers in an effort to find possible quality or efficiency problems. Do you think this secret recording is ethical? Why or why not?

11 | PC Video Cameras and Web Cams

Estimates suggest that currently more than 9,000 Web sites use Web cams. Web cams are used to put everything from college dorm rooms to taxi cabs on the Web. The first personal Web page to use a Web cam was the JenniCam, which showed the daily life of a college co-ed. The site started in 1996 as a project for a computer class and still receives more than 4.5 million hits a day. Web cams also have more practical uses. Recently, some day-care centers have installed Web cams so parents can use the center’s Web page to check on their children. This use of Web cams, however, has not been without controversy. Due to the usually slower speeds of Web cam videos, it can be difficult for parents to tell the difference between a day care worker’s loving pat on the head and a rap on the noggin.

12 | Scanners and Reading Devices

In general, scanners and reading devices increase input accuracy and efficiency by reducing the role of the weak link in the input process – the human operator. Optical readers are highly specialized. Devices that read one set of codes, marks, or characters may not be able to read another.

An optical mark reader identifies the position, not the shape, of a mark. You may be familiar with optical marks from tests in which you use a pencil to fill in ovals or rectangles that represent the answers.

Bar codes minimize input errors, keep inventories up to date, help to track sales trends, and eliminate the need to price individual items. The identifying numbers on a UPC code can be entered if the scanner fails. This number is not the item’s cost – prices are obtained from a database when the item is scanned. Some consumer groups, however, claim price databases not always are accurate, and that the absence of individual item pricing makes comparing costs difficult.

The MICR font, adopted by the American Banking Association in the 1950s, is standard throughout the banking industry. The special shapes of MICR characters make them easier for a machine to read. MICR readers can interpret magnetic characters even if someone has written over them. If the magnetic ink on a check is damaged, however, the data must be typed into the system. The importance of MICR readers to the banking industry is staggering – half of the U.S. population would be needed to process checks if it were done manually.

13 | Input Devices for Physically Challenged Users

Some input aids for physically challenged people are relatively simple (such as keyguards), while others are much more sophisticated (such as head-mounted pointers). Chin-operated joysticks also are available. Another input system, called Eyegaze or ERICA (Eyegaze Response Interface Computer Aid), was developed by Thomas Hutchinson of the University of Virginia, who as a boy was paralyzed temporarily by an accident. With a camera mounted on the computer and directed at a user’s eye, the Eyegaze system can determine to within a ¼ inch where on the screen a user is looking. By staring at the spot for about ¼ second, a user can activate a choice. Adaptive technology has given many people their best opportunity to communicate, work, and play. As a six-year-old victim of cerebral palsy said in her first message, “It’s about time.”

The Components of the System Unit

Chapter 4: The Components of the System Unit


  1. Describe the components in the system unit
  2. Explain how the CPU uses the four steps of a machine cycle to process data
  3. Define a bit and describe how a series of bits represents data
  4. Differentiate between the various types of memory
  5. Describe the types of expansion slots and cards in the system unit
  6. Explain the difference between a serial, a parallel, and a USB port
  7. Describe how buses contribute to a computer’s processing speed
  8. Identify components in a notebook computer
  9. Identify components in a handheld computer

Chapter 4 presented the components in the system unit, described how memory stores data, instructions, and information, and discussed the sequence of operations that occur when a computer executes an instruction. The chapter included a comparison of various microprocessors on the market today.

1 | Describe The Components In The System Unit

The system unit, sometimes called the chassis, is a box-like case housing the electronic components of a computer that are used to process data. System unit components include the processor, memory module, cards, ports, and connectors. Many of the system unit’s components reside on a circuit board called the motherboard. The motherboard contains many different types of chips, or small pieces of semiconducting material, on which one or more integrated circuits (IC) are etched. An integrated circuit is a microscopic pathway capable of carrying electronic current. Each IC can contain millions of transistors, which act as switches for electronic signals.

2 | Explain How The CPU Uses The Four Steps Of A Machine Cycle To Process Data

The central processing unit (CPU), also called a processor, significantly impacts overall computing power and manages most of a computer’s operations. The CPU contains the control unit and the arithmetic/logic unit. The control unit directs and coordinates most of the operations in the computer. For every instruction, the control unit repeats a set of four basic operations called the machine cycle: (1) fetching the instruction or data item from memory, (2) decoding the instruction into commands the computer understands, (3) executing the commands, and, if necessary, (4) storing, or writing the result to memory. The arithmetic/logic unit (ALU) performs the execution part of the machine cycle. Specifically, the ALU carries out three operations:

  • Arithmetic operations – performing calculations, which include addition, subtraction, multiplication, and division
  • Comparison operations – comparing data items to determine if the first item is greater than, equal to, or less than the other item
  • Logical operations – working with conditions and logical operators such as AND, OR, and NOT
  • Compare and contrast various personal computer processors on the market today

A personal computer’s CPU usually is contained on a single chip, which some call a microprocessor. Intel is a leading manufacturer of personal computer processors. Most high-performance PCs use a processor from Intel called the Pentium® processor. A second Intel brand, called the Celeron™, is designed for less expensive PCs. Two more brands, called the Xeon™ and Itanium™ processors, are ideal for workstations and low-end servers. Intel-compatible processors have the same internal design as Intel processors and perform the same functions, but are made by other companies and often are less expensive. An alternative design to the Intel-style processor, the Motorola processor, is found in Apple Macintosh and Power Macintosh systems. A new type of processor designed for lower-costing personal computers and Internet appliances, called an integrated CPU, combines functions of a processor, memory, and a video card on a single chip. Today’s processors are equipped with MMX™ technology, a built-in set of instructions that manipulates and processes multimedia data more efficiently. Intel’s SSE instructions and AMD’s 3DNow!™ are two other technologies that improve a processor’s performance of multimedia, the Web, and 3-D graphics. To optimize and extend battery life for notebook computers, Intel® mobile processors use SpeedStep™ technology and AMD processors use PowerNow!™ technology.

3| Define A Bit And Describe How A Series Of Bits Represents Data

Most computers are digital, meaning they understand only two discrete states: on and off. These states are represented using two digits, 0 (off) and 1 (on). Each on or off value is called a bit (short for binary digit), the smallest unit of data a computer can handle. Eight bits grouped together as a unit form a byte. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters including numbers, letters of the alphabet, punctuation marks, and other characters.

The combinations of 0s and 1s used to represent data are defined by patterns called coding schemes. Popular coding schemes are ASCII, EBCDIC, and Unicode. Coding schemes make it possible for humans to interact with a digital computer that recognizes only bits. Every character you type on a keyboard is converted into a corresponding byte, a series of on/off electrical states the computer can process.

4 | Differentiate Between The Various Types Of Memory

Memory is a temporary storage place for data, instructions, and information. Memory stores the operating system, application programs, and the data processed by application programs. A byte is the basic storage unit in memory. Memory size is measured by the number of bytes available for use. A kilobyte (KB or K) of memory is approximately one thousand bytes, a megabyte (MB) is approximately one million bytes, and a gigabyte (GB) is approximately one billion bytes. The system unit contains several types of memory.

RAM (random access memory) consists of memory chips that the processor can read from and write to. Most RAM is volatile memory, meaning that its contents are lost when the computer’s power is turned off. Two basic types of RAM chips are dynamic RAM and static RAM. Dynamic RAM (DRAM) must be re-energized constantly or it loses its contents. Static RAM (SRAM) is faster and more reliable than DRAM and has to be re-energized less often, but it is much more expensive.

Memory cache, also called a cache store or RAM cache, improves processing time by storing frequently used instructions and data. ROM (read-only memory) refers to memory chips that only can be read and used; that is, they cannot be modified. ROM is nonvolatile memory (NVM), meaning that its contents are not lost when the computer’s power is turned off. A variation of the ROM chip, called programmable read-only memory (PROM), is a blank chip on which you can place items permanently.

Flash memory, also known as flash ROM or flash RAM, is nonvolatile memory that can be erased electronically and reprogrammed. Complementary metal-oxide semiconductor (CMOS) memory, another type of memory chip, stores configuration information about the computer and uses battery power to retain information when the power to the computer is off.

5 | Describe The Types Of Expansion Slots And Cards In The System Unit

An expansion slot is an opening, or socket, where you can insert a circuit board into the motherboard. These circuit boards – called cards, expansion cards, boards, expansion boards, adapters, adapter cards, interface cards, add-ins, or add-ons — add new devices or capabilities to the computer. Four types of expansion cards found in most computers are a video card, a sound card, a network interface card, and a modem card.

A video card converts computer output into a video signal that is sent through a cable to the monitor, which displays an image. A sound card enhances the sound-generating capabilities of a personal computer by allowing sound to be input through a microphone and output through speakers.

A network interface card (NIC) is a communications device that allows the computer to communicate via a network. A modem card is a communications device that enables computers to communicate via telephone lines or other means. Many of today’s computers support Plug and Play, a capability with which the computer automatically can configure expansion boards and other devices as you install them.

Notebook and other portable computers have a special type of expansion slot used for installing a PC Card, which is a thin credit card-sized device that adds memory, disk drives, sound, fax/modem, and communications capabilities to a mobile computer.

6 | Explain The Difference Between A Serial, A Parallel, And A USB Port

A cable often attaches external devices to the system unit. A port is the interface, or point of attachment, to the system unit. Ports have different types of connectors, which are used to join a cable to a device. Male connectors have one or more exposed pins, while female connectors have matching holes to accept the pins. Most computers have three types of ports: serial, parallel, and USB. A serial port is a type of interface that connects a device to the system unit by transmitting data only one bit at a time. Serial ports usually connect devices that do not require fast data transmission rates, such as a mouse, keyboard, or modem. A parallel port is an interface that connects devices by transferring more than one bit at a time. Many printers connect to the system unit using a parallel port. A universal serial bus (USB) port can connect up to 127 different peripheral devices with a single connector type, greatly simplifying the process of attaching devices to a personal computer.

7 | Describe How Buses Contribute To A Computer’s Processing Speed

Bits are transferred internally within the circuitry of the computer along electrical channels. Each channel, called a bus, allows various devices inside and attached to the system unit to communicate with each other. The bus width, or size of the bus, determines the number of bits that can be transferred at one time. The larger the bus width, the fewer number of transfer steps required and the faster the transfer of data. In most computers word size (the number of bits the CPU can process at a given time) is the same as the bus width. Every bus also has a clock speed. The higher the bus clock speed, the faster the transmission of data, which results in applications running faster. A computer has two basic types of buses. A system bus connects the CPU to main memory. An expansion bus allows the CPU to communicate with peripheral devices.

8 | Identify Components In A Notebook Computer

Users with mobile computing needs often have a mobile computer, such as a notebook computer and/or handheld computer. A notebook computer, also called a laptop computer, can run either using batteries or using a standard power supply. In addition to the motherboard, processor, memory, sound card, PC Card slot, and drive bay, the system unit for a notebook computer also houses other devices, such as the keyboard, pointing device, speakers, and display.

9 | Identify Components In A Handheld Computer

Handheld computers run strictly on battery. Similar to desktop and notebook computers, handheld computers have a system unit that contains electronic components that process data. A handheld computer’s system unit also contains a display and may house speakers and some form of keyboard and/or pointing device. Handheld computers often have an IrDA port so you can communicate wirelessly with other computers. Many also include a serial port.

Expand Your Knowledge

  1. The system unit
  2. The CPU
  3. Processor comparison
  4. Data representation
  5. Memory
  6. Expansion slots and expansion cards
  7. Ports
  8. Buses
  9. Notebook computers
  10. Handheld computers

Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.

1 | The System Unit

The motherboard in the system unit contains different types of chips. Manufacturers package chips so the chips can be attached to circuit boards, such as the motherboard. Types of chip packages include:

  • Dual inline package (DIP), which consists of two parallel rows of downward-pointing thin metal feet (pins)
  • Pin grid array (PGA) package, which holds a larger number of pins because the pins are mounted on the surface of the package
  • Flip chip-PGA (FC-PGA) package, which places chips on the opposite side (flip side) of the pins
  • Single edge contact (SEC) cartridge, which connects to the motherboard on one of its edges

2 | The CPU

The power of personal computer processor chips (the chips that contain the CPU) has grown at an astounding rate. As chips become older and more widely used, price cuts usually are introduced.

Several factors affect CPU processing speed. CPUs in most of today’s personal computers use pipelining, a technique that increases processing speed by beginning execution of a second machine cycle instruction before the first instruction is completed. CPUs also use high-speed storage locations, called registers, to hold data and instructions temporarily. The control unit relies on a small chip called the system clock to synchronize all computer operations. The speed at which a processor executes instructions is called clock speed, or clock rate, and is measured in megahertz (MHz). The system clock is a major factor affecting processor speed. A higher clock speed means the CPU can process more instructions per second.

3 | Processor Comparison

Although once frequently used, the term “microprocessor” is much less common today.
Sometimes you can upgrade your processor to increase the computer’s performance. There are three forms of upgrades:

  • With a chip for chip upgrade, the existing processor chip is replaced with a new one
  • With a piggyback upgrade, the new processor is stacked on top of the old one
  • With a daughterboard upgrade, the new processor is on a small circuit board (the daughterboard) that plugs into the motherboard

The past three years have seen a steady drop in the cost of computers. PC prices plunged as a result of lower prices for processors, memory chips, and hard drives. Consumers also are showing increased interest in new less powerful, but less expensive, personal computers that work perfectly well for the most popular uses – word processing, Internet access, and spreadsheet applications. The surge in low-priced computer sales has had an impact on Intel, the world’s largest processor manufacturer. By focusing on making inexpensive processor chips, rivals AMD and Cyrix are making inroads into Intel’s dominance. Intel’s response, the Celeron™, has proven popular, but the lower-priced chip offers a smaller profit margin.

4 | Data Representation

Just as the decimal system (10 digits) is suited to human anatomy (10 fingers), the binary system (2 digits) is perfect to represent the on-off states (2 states) of a computer. Basic coding standards make it possible for components within computers to communicate, allow manufacturers to be confident that the components they produce will operate correctly in a computer, and enable consumers to purchase components that are compatible with their systems. In the ASCII-8 and EBCDIC codes, the first four characters represent the zone, and the last four characters represent the digits 1 through 8. ASCII, originally a seven-bit code, was expanded to eight bits in an effort to provide for symbols used in other nations. Unicode, a 2-byte (16-bit) code, can represent 216, or 65,536, characters. The system employs the codes used by ASCII and also includes other alphabets (such as Cyrillic and Hebrew), special characters (including religious symbols), and some of the “word writing” symbols used by various Asian countries.

5 | Memory

Because computers use the binary number system, the actual values for the units in which memory and storage are measured are based on powers of 2. For example, one kilobyte = 210 = 1,024.

RAM’s volatility, and its ability to be changed, are its most distinguishing characteristics. When RAM is purchased it comes in banks of nine chips – eight are needed to represent a byte and the ninth is needed for parity. RAM chips usually are packaged on small circuit boards called single inline memory modules (SIMMs) or dual inline memory modules (DIMMs) that are inserted into the motherboard. During the past 20 years, the price of RAM has dropped an average of 20 percent each year, but its capacity has more than doubled every two years.

Similar to flash ROM, another variation of ROM, called EEPROM (electrically erasable programmable read-only memory), can be erased electrically and rewritten. Because of its nonvolatile nature, EEPROM is used in electronic cash registers to store item prices.

The amount of time it takes the processor to read data from memory, called access time, directly affects how fast the computer can process data. Memory access time is measured in terms of nanoseconds, or billionths of a second.

6 | Expansion Slots And Expansion Cards

Plug and Play was a much-touted feature of the Windows 95 and Windows 98 operating systems.

A PC Card slot, usually located on the side of a notebook computer, allows a PC Card to be changed without having to open the system unit. There are three types of PC Cards:

  • Type I cards add memory capabilities to the computer
  • Type II cards contain communications devices
  • Type III cards house devices such as hard disks

7 | Ports

Port connectors are devised to be foolproof – each is designed so it can fit only one type of socket in only one correct position. Serial ports always are male on the system case. Cables connected to parallel ports often are employed over shorter distances.
Special-purpose ports include:

  • 1394 port – a port that can connect multiple devices requiring faster data transmission speeds such as digital cameras and DVD drives
  • MIDI (musical instrumental digital interface) port – a special type of serial port designed to connect the system unit to a musical instrument
  • SCSI (small computer system interface) port – a high-speed parallel port used to attach peripheral devices such as disk drives and printers
  • IrDA port – a port that allows wireless devices to transmit signals to a computer via infrared light waves

8 | Buses

A highway analogy can help clarify how bus width affects the speed of data transfer. Data moves like cars – the more lanes (greater the bus width) the faster the traffic (data) flow. Ideally, buses used to transfer data should be large enough to use the processing power of registers. Sometimes, however, manufacturers reduce bus size to cut costs.

Word size, which indicates the number of bits processed in each machine cycle, has been compared to the amount of coffee produced with each turn of a coffee grinder’s handle. Theoretically, if word size doubles then processor throughput also could double.

The types of expansion buses on a motherboard determine the types of cards you can add to a computer. Types of expansion buses include:

  • An ISA (Industry Standard Architecture) bus, the most common and slowest expansion bus, connects to devices such as a mouse, modem card, sound card, and low-speed network card
  • A local bus is a high-speed expansion bus used to connect higher speed devices such as hard disks
  • An Accelerated Graphics Port (AGP) is a bus designed by Intel to improve the speed with which 3-D graphics and video transmit
  • The universal serial bus (USB) and 1394 bus are buses that eliminate the need to install expansion cards into expansion slots
  • A PC Card bus is the expansion bus for a PC Card

9 | Notebook Computers

A typical notebook computer often has a keyboard/mouse, IrDA, serial, parallel, video, and USB ports. The keyboard/mouse port allows users who are uncomfortable with a notebook computer’s smaller keyboard and less-traditional pointing devices (often a touch pad or pointing stick) to connect a full-sized keyboard or a mouse to the computer.

10 | Handheld Computers

One of the most popular handheld computers is the Palm Pilot from 3Com. First introduced in 1996, a recent version, Palm IIIc, offers a color screen and an expandable, full-sized keyboard. Another pioneering handheld computer is Visor from Handspring. Visor runs the Palm operating system and features an expansion slot that can accommodate add-ons such as digital cameras and music players. Visor’s greatest innovation, however, may be the slot in the back, which can accommodate modules with various functions including a pager, an MP3 music player, videogame cartridges, and a module that converts the Visor into a cell telephone.