Glossary of Computer-Related Terms

Writing a computer program can be a lot of work. Today's commercial programs are large and complex and getting everything to work correctly takes a lot of testing and rewriting. Typically, a program is planned out on paper as to just what it will do and how it will do it. Then a programmer starts to work to create the program. When he/she has the main parts of the program functioning, it is distributed (usually only within the company) for others to test and evaluate. This is called an 'Alpha' release. (Alpha and Beta are the first two letters of the Greek alphabet - and they are where we get the word 'Alphabet' from.) At this point, many errors are reported and many desired features are suggested. Now the programmer(s) go to work correcting the errors and adding new features. Once they feel the product is ready, they release it again as a Beta. In many cases, Beta programs are made available to selected individuals outside of the company (in particular, authors who may write books or reviews of the new software, and experienced users who will test and report problems back to the programmers). In some cases, as with browsers, Beta versions are available to anyone. Although a Beta version may have almost all of the features of the final version, it most likely contains errors or bugs that could cause problems for the user's computer. Beta programs often run slower or take up more storage space. Unfortunately, even with this testing procedure, too many programs are released as final versions before Beta testing has found all of the errors.
The smallest piece of information, a bit has just two values signified by a 1 or a 0 and commonly thought of as "off" or "on". At its most basic level, all a computer can manipulate is bits. However, bits are usually combined in groups of 8, 16, etc. to convey more data. For example, a group of 8 bits is called a byte and can be used to represent one of 256 possibilities. see byte
Boot Up
Some networks require that certain files be loaded in early in the computer start up sequence to enable the computer to join the network. Because the floppy drive is usually checked early in the procedure, these files are stored on a floppy that is called a "Boot Up" disk. In addition, some DOS games require a tremendous amount of memory to run. (DOS programs can only run in the first 640K of memory - but other programs must also use this space.) In order to free up as much of this space as possible, some programs which may be needed for many activities, but not the game, are deliberately not loaded in to make room. Other programs may be moved to a higher location in memory. The easiest way to achieve these goals is to write special autoexec.bat and config.sys files that only the game uses and to store these files on a boot up floppy. The boot up floppy should be write protected if at all possible. (In some cases, network or game programs may insist on being able to write to the disk.)
A browser is an application designed to read documents formatted in HTML. These documents are usually posted to the Internet, particularly the World Wide Web, although they can exist as files on your disk as well. The most popular browsers are Netscape's Navigator (part of its Communicator suite) and Microsoft's Internet Explorer. Between them they probably account for over 90% of all browsers in use today.
This is the "superhighway" inside the computer. Data moves from one location to another over the bus. Pentium systems usually use a newer bus design than 80486 or older machines. This is one reason why many dealers will advise you to get a new motherboard when upgrading.
As described above, a byte is made up of 8 bits. Starting at the right, each bit has only two possible values, but, as you add additional bits, the number of possible values increases by powers of two: 2, 4, 8, 16, 32, 64, 128, 256. It can be helpful to think of a byte as the unit of data required (or storage space required) for a letter or character such as "A", "x" or "+".


A cache - pronounced 'cash' - is data temporarily stored on your hard drive. The purpose of a cache is to make devices that are relatively slow (such as a CD-ROM drive or the Internet) appear to be much faster by storing data the computer thinks you will want in the cache. To ensure that your whole hard drive is not used up storing data you may never want to see again, only a certain percentage of your drive's available space is used. However, you can change the percentage - or erase the cache altogether - if you want to.
The Central Processing Unit is the brain of the computer. Today there are several manufacturers producing CPU chips for PC's. However, the vast majority of CPU chips are manufactured by Intel. The following chip designations have been used in PC's: 8088, 8086, 80286. 80386, 80486, Pentium and Pentium Pro. Motorola manufactures the 68000 family and Power PC chips which are the brains for the Macintosh and other computers (Atari ST and Amiga).


A CD-ROM is essentially the same as an audio CD. It stores approximately 700 megabytes of data. Just as an audio CD can be erased and re-recorded, the CD-ROM's data can not be changed (hence ROM- Read only memory). There are CD-ROM drives that can store information on recordable CD's. However, this is a one-time process. Newer CD's, holding much more data will soon be available, known as DVD disks.


The clipboard is a temporary storage location. When you copy or cut a selection, it is stored on the clipboard. You can then move to a new location in your current document, or a different document, or a different document in a different program and paste the selection in. Note, however, that only one item can be stored in the clipboard. When you copy or cut a new item, the previous item is lost. (You can, however, obtain programs that increase the usefulness of the clipboard - including storing more than one item.)


An acronym that describes its construction. CMOS is essentially a special kind of memory that is long lasting (a "watch" battery will power it for about three years), but that can be changed easily. It is used to store the current date and time and information about your computer system, especially the hard drive(s). If this information becomes corrupted, you may not be able to access your hard drive.

Control Stick

Some notebook computers use this device (which resembles a very small joystick placed in the middle of the keyboard) as a replacement for the mouse. Some people find the device easy to use while others dislike it.


In Windows, the cursor is usually a straight, thin vertical line that positions itself just after the last letter typed. Most commands will take effect at the cursor position. In older, DOS based applications the cursor took different shapes including an underline and a rectangular block.



An organized collection of data such as a mailing list, school grades or a company inventory.


We will be using this term in the broad sense of anything you create using a program. This would include a letter created with a word processor, a picture or graphic, a spreadsheet worksheet, database information, or high game scores.


The media from which data is read and to which data is often stored. Many disks - such as floppy and hard disks - store data magnetically. Such disks allow the computer to read, write and erase data. Other media involve burning part of the medium with a laser to store data. These disks - such as CD-ROMs and new DVD-ROMs - allow the computer to read data from them. A special drive is required to store data on these laser disks.

Double Density

Originally, computer disks were "Single Density". In time, manufacturers were able to double the storage capacity of a disk which was then called "Double Density". By the time the 3.5" format was adapted for use by PCs, they were already at double density holding 720 kilobytes of data. Today, floppy disks have again doubled in capacity and are now called "High Density". These high density disks store 1,440 kilobytes or 1.4 megabytes of data.


A drive is a mechanical device that is able to read and (often) write data on a media such as a disk or tape. In most cases, the media is removable. The exception to this is the hard (or fixed) drive where the media is an integral part of the device.


Certain devices attached to your computer (such as the printer and the mouse) require small programs that allow them to work with DOS or Windows programs. These small programs are called "Drivers". With Windows 95, many drivers come built in. However, some older and many very new devices may need to have a driver loaded before they will work properly. In this case, you will receive a disk (or CD-ROM) with the device that contains the required drivers. You may also find improved drivers on manufacturers' websites.


A new disk and drive format resembling a CD-ROM but capable of 8 times (approximately) the storage capacity. Future DVD devices will store even greater capacities and may be writable. Although this text seldom refers to a DVD drive, for our purposes, DVD and CD-ROM are essentially interchangeable. (The drive and disk are similar in size, appearance and function.) DVD drives will also be able to read CD-ROM disks (but not vice versa, unfortunately). One DVD disk can hold a feature length movie (stored at broadcast quality) along with several audio tracks (including different languages) and other materials.



Floppy Disk

Originally available in 8" (inch) and 5.25" sizes, floppy disks today are 3.5" and available in high density (HD). Today's disks store about 1.4 megabytes of data using both sides of a high density disk. Losing favor because of their (relatively) limited capacity, their cost has dropped to about 50_ per disk. A few drives exist that handle only double density (DD) disks which stored a maximum of about 720 kilobytes using both sides of the disk. (These disks are becoming almost impossible to buy.)


The font is the 'style' of the type or lettering used in a document. There are two large groups of fonts: Serif and Sans Serif. "Serif" refers to the small accents added to many letters, while "Sans" simply means "without". Study these two examples:

T J S 

Sans Serif


Fonts come in "families". The Arial(which is a 'sans serif' font) family of fonts may come in normal, bold, condensed, etc. versions. The most popular 'serif' font is probably Times New Roman. (These are popular fonts for Windows computers. Other computers have similar fonts although they may bear a different name.) Some fonts are used for main text as here, while others may be used only for headlines or special effects (such as the font used to create our 'FoDOweb' logo at the top of this page).


Game Port

The game port is used to connect a joystick to the system. Most modern systems come with a game port built in. In addition, many sound cards provide a game port which may also be used to connect MIDI instruments.


Approximately 1,000,000,000 bytes. Modern computers come with hard drives of 1 gigabyte or larger in size.


Hard Disk

A hard disk (or hard drive or fixed drive) is located inside the computer's system box. Unlike "floppy" disks where the storage material is flimsy plastic, these disks are usually made of glass or aluminum. They are also covered with a much denser and higher quality magnetic coating. There are often several disks stacked above each other in a typical drive. The drive is sealed to keep out any contaminants such as dust, smoke or hair particles which could destroy the drive. These drives store much more data than floppy disks or even CD-ROM disks. Typical hard drives today store from 5 to 25 gigabytes of data, HTML

HyperText Markup Language is a set of commands that determine how text and graphics will be displayed in a program called a browser. Although usually used with World Wide Web documents, any document can be formatted in HTML and displayed in a browser or many word processors.

Hard Disk

Often used to refer to either or both of the drive itself and the storage media. Early hard drives had a capacity of 5 to 10 kilobytes and cost several hundred dollars. Today, hard drive capacities start at about 1 gigabyte and go up to 5 gigabytes or more. A 1 "gig" drive costs less than $300. Hard drives use both sides of the disk and often use more than one disk in their construction. They are permanently mounted inside the system box. (There are, of course, exceptions.)

High Density

High density 3.5" disks store about 1.4 megabytes of data. An even higher capacity disk has been developed, but, thanks in part to the CD-ROM, this format has not (and probably will not) catch on. High density disks have a second square hole at one end (all 3.5" disks have one hole - for write protection, see below).



A network of computers (usually mainframe) that are spread throughout the world. Communications can be sent from any one computer to any other computer by passing through various computers on the way. The best known aspect of the Internet (often called just the 'net') is the world wide web (or just 'web').



A device used to control the "action" on the monitor's screen. Similar to the sticks on old airplanes, it can control movement in 8 or more directions and supports one or two "fire" buttons. Most often used with games, although most games provide for alternate methods of control.



Commonly thought of as 1,000 bytes. Actually, since it is a power of two, a kilobyte = 1,024 bytes (210). Until the mid 1980's, the computer's internal memory was normally measured in kilobytes. The Commodore 64 had 64 kilobytes, and an IBM compatible computer could have up to 640 kilobytes.




Approximately 1,000,000 bytes. Computer memory is currently measured in megabytes. Modern computers usually have 16 or more megabytes of memory.


Megahertz is the measurement used for timing the speed of a CPU. Early computers such as the Apple ][ and Atari 800 operated at about 1 megahertz. The first PC's ran at 4.7 megahertz. Current Pentium and Pentium Pro CPU's run at 200, 233, 266, 300, 350, 400 and higher megahertz.


A contraction of "modulate - demodulate", the modem transforms computer signals into a form that can be sent over normal telephone lines and back into computer readable form at the other end. Today's modems are capable of data, fax and voice transmission. Data can be transferred at speeds of 28.8 kilobits per second or faster (33.6 and 56k). For sporadic or fax use, speeds of 9,600 bits per second to 14.4k are fast enough. For accessing the Internet, the fastest speed that you can afford (and that your telephone lines will support) is desirable. There are also devices that work with TV cable lines, with special ISDN telephone lines and with high speed data lines. There are currently three 56.6k standards: flex, X2 and v.90. v90 is the official version and all new modems support this (and may support one of the other two as well). Older or cheaper modems may only support one of the unofficial standards, although most (not necessarily all) can be upgraded to the new standard.


The monitor allows the computer to display information to the user. Typical monitors today are labeled "SVGA" for "Super VGA" (Video Graphics Array). Monitors come in sizes from 14" to 21" and perhaps more. Typical resolutions include 640 (wide) x 480 (deep), 800 x 600, 1024 x 768 and higher. (These represent the number of "pixels" or controllable dots). Monitors can display 16, 256, 16 bit and 24 bit color (or higher). (16, 256, 65,536 and 16,777,216 colors) Better monitors have a dot-pitch of .028 or lower (lower is better) and are non-interlaced.


The main circuit board in a computer. All of the major components are either mounted on the motherboard or attached to it via a "daughter-board". (Sound cards and video cards are examples of "daughter-boards".) The quality of the motherboard can affect the performance of the computer and can determine the extent to which the computer can be "upgraded" economically. Although it is possible to upgrade an 80486 chip to Pentium speed, it is often desirable to replace the motherboard as well in order to realize maximum performance gains. (In this case, it will probably also be necessary to replace the video board since Pentium systems use a different bus standard.)


About the size of a deck of cards, a mouse is essentially, a trackball turned on its back. A mouse glides over the desk (or a mouse pad) moving a small ball which, in turn, moves tint "axles" that transmit the movement data to the computer. (Some mice use optical control instead of the wheel and "axles".) As the mouse moves, a pointer (usually shaped like an arrow) moves on the computer screen. The mouse has 1 to three buttons to interact with the objects on the screen. Very recent "mice" have added a "wheel" between the mouse buttons which allow the user to scroll text without using the scroll bars on screen. A mouse is used to activate objects on the screen and thus control the operation of the computer.

Mouse Pointer

The mouse pointer can take on many various shapes, but it normally assumes the shape of an arrow pointing at a slight angle or an hourglass. The hourglass indicates that the computer (actually the CPU) is currently occupied with some activity. The mouse pointer moves as the user moves the mouse. The mouse pointer is used to manipulate objects on the screen (including the cursor).


(Motion Picture Experts Group) is a compressed video format. Currently, some movies as well as normal video are available in this format. Although it is possible to run this format with just software, usually a hardware/software solution gives the best results. DVD videos which should start appearing by mid 1997 will use MPEG 2, a more sophisticated, higher quality format.



Operating System

Every computer needs an operating system that controls how the user interacts with the computer and how the computer interacts with the user and with the hardware that is part of the computer system. For years, IBM compatibles used an operating system known as "DOS" (Disk Operating System). The current version of DOS is 6.2. In recent years, the Windows environment has taken over. Although Windows 3.x is more properly thought of as an add-on to DOS, it is so fundamentally different from DOS that it is not inappropriate to consider it a separate operating system. The latest version Windows 95 has incorporated some features of DOS, so that it truly is a new operating system. IBM compatibles can use other operating systems such as OS/2 or UNIX.


Parallel Port

There are a number of ports or connection points on every computer. There are ports for the keyboard, monitor, mouse, and other devices. The parallel port is used to connect a printer. Many other devices can also use the parallel port but, in most cases, they provide a "pass-through" connector so that a printer can also be attached. Parallel ports transfer 8 bits of data at once (in parallel).


Another device to display computer output, this time on paper. Older printers include daisy-wheel printers (essentially a controllable typewriter), and dot-matrix. Dot matrix printers form letters and graphics by controlling 9 or 24 small wires that create dots of ink on the screen. Better dot-matrix printers produce output that is difficult to distinguish from typewritten or laser output. Dot-matrix printers can often print in color (although they may require an add-on kit). The most popular general purpose printer today is the inkjet. These printers spray tiny dots of ink on the paper. Most inkjets sold today have color capability built in. Today, some inkjet printers produce better output than the most expensive laser printer, approaching photographic quality. However, most businesses prefer laser printers for several reasons: usually faster output, less expensive to operate (especially for large capacity use), and, until recently, slightly better print quality. Black and white laser printers are only slightly more expensive than moderate priced inkjets. Color lasers are, however, still very expensive.


A program is simply a set of instructions that tell the computer what to do one step at a time. The operating system is a program as are such applications as WordPerfect or Lotus 123. Programs are written in one of several computer programming "languages" such as BASIC, Assembler, C, C++, or Java.




An acronym for Random Access Memory. This is the memory inside the computer. This memory is active only while the computer has power. Any loss of power, even if only for a fraction of second, will erase whatever is stored in this memory. This memory must hold the operating system (explained later), the program you are running, and any data you are creating. Today's computers have 8 or more megabytes of RAM.


An acronym for Read Only Memory. This is the basic set of instructions the computer needs to display a letter on the screen or begin the process of retrieving information from a disk drive. This memory is permanently stored on a chip. It can not be changed except by replacing the chip that holds the ROM.



Similar to the "copy" feature of a photo-copier, a scanner can "read" text or pictures and send the data to the computer. There, an OCR (Optical Character Recognition) program will turn "images" back into editable text. Today's scanners are capable of excellent results that require little if any editing or graphic clean-up. Photographs can be scanned with amazing results.

Serial Port

Today's computers usually come with two serial ports. One is used for the mouse. The other can be used for various purposes but most commonly is used to connect an external modem. (Some printers, notably laser printers, may connect with the serial port.) The serial port transfers one bit of data at a time.

Sound Card

A sound card is an "add on" board that allows the computer to process "surround sound" quality sound. Most computers sold today come with a sound card - although better quality cards can often be added. Most games and CD-ROM use requires (well, works a lot better with) a sound card.


A spreadsheet is an application that stores data in a grid of columns and rows. The spreadsheet can perform calculations using formulas and/or built-in functions on selected data.

Storage Devices

We've already looked at the most common devices - disk drives of various types. Here's a few more: Syquest manufactures several different (usually not compatible) drives that use a removable hard disk (platter) in a cartridge. Speeds approaching normal hard drive rates are possible. Various manufacturers sell "Zip" drives that use a technology similar to Syquest but allow lower capacity and lower cost. Still more drives using optical technology are available. These drives typically come in three configurations: internal (such as a hard drive or floppy) parallel port (external that connects with a cable to the parallel port with an additional port so that you can still use your printer; and external SCSI that requires a card inside the computer and a cable.


Super VGA is the current standard for monitors. It supports resolution of 1024 x 768 pixels or higher in up to 65 million colors. Most monitors sold today are SVGA.



A magnetic media approximately the size of an audio cassette or 8mm video cassette. Data is stored and retrieved from the cassette in much the same manner as from an audio or 8mm cassette. Used primarily to back up large amounts of data such as is stored on hard drives.

Touch Pad

A rectangular surface that detects the movement of your finger. It is a replacement for the mouse, especially on portable machines. Currently gaining in popularity.


Originally a substitute control device for a joystick, it replaced the movable stick with a ball. It provided better control for some games (such as Missile Command) but less control for most other games. Trackballs are now used on some computers (usually portables) instead of a mouse.



Version (Software Version)

Software publishers, such as Microsoft and Netscape (who write programs for you to use on your computer) are always trying to improve their product. Improvements usually fall into two classes: Refinements and Enhancements. A refinement is a change in a program that eliminates an error (or 'bug') or that makes the program work more efficiently. An enhancement is a new 'feature' that allows the program to do something it couldn't do before. Every time a program is refined or enhanced, it is considered to be a new 'version' of the program. Until recently, program versions were given numbers such as 1, 2, 3, etc. Minor changes or refinements in a program received a decimal number such as 1.1, 1.2. 1/21, etc. For example, there were two major versions of Windows before Windows 3 came along. (Both of these versions were little used, but that's another matter.) Windows 3 was released in 1990. However, it was not until Windows 3.1 was released about 1992 that Windows started to become popular. Windows 3.1 was classified as a minor change, although, in fact, some very significant changes and improvements were introduced. Since then, however, a few minor refinements have been released such as Windows 3.11. With a few exceptions, you could tell how many major revisions a product had gone through by checking its version number. In general, (and in theory) the higher the number, the more features and the more stable and efficient the program should be. Because of this fact, some companies deliberately skipped numbers to make their product seem more 'established' than it was. In other cases (such as with Microsoft's Office suite, some numbers were skipped so that all programs within the suite had the same version number. With Windows 95, Microsoft introduced a change. Now versions would be identified by the year in which they were released rather than an arbitrary number. This has some benefits, but it also opens the door for companies to make minor refinements and release them as new versions each year. Unrfortunately, a tradition has grown up in the software field where customers are charged even for minor refinements or to fix problems with the software. If you own a lot of programs, you could spend a lot of money every year or so just keeping the programs you already own up to date.

Video Card

All computers require a video card. The card usually contains memory (RAM) that is reserved for the video (monitor) display. For monitor displays at high color and resolution, 2 or more megabytes of RAM are required. Video cards can vary greatly in quality (as can sound cards) so it pays to study the specifications before buying a new computer.


An older format, it supports resolutions of 640 x 480 or higher. While a VGA monitor is quite serviceable, it cannot compete with SVGA (super VGA) where high resolution is required. Any monitor you consider purchasing should support at least 640 x 480 and preferably 800 x 600 or higher. (These numbers refer to the number of controllable picture elements [dots or 'pixels'] across and down the screen.) 256 colors is an absolute minimum. (Screen resolution and color are determined by both the quality of the monitor and the video card.)


A virus is simply a small program. Every program is just a set of instructions that the computer follows (although in most cases the computer selects a certain portion of the instructions to follow in response to the user's actions). Unfortunately, a virus is created by a very clever programmer with nothing useful to do. The virus is designed to do two things: to spread to as many different computer systems as possible (which is the reason for its name) and to make its presence known to the computer user at some pre-determined situation. Once a virus is loaded (or down-loaded from the Internet or some BBS) it quickly copies itself to floppy disks that are inserted into the computer's floppy drive. It may also attach itself to program files on the hard drive. If it does attach itself to hard drive files, it will be active whenever the computer is on. If it does not attach itself to a file on the hard drive, the virus will be removed when the computer is turned off. However, whenever an infected disk (a disk with a copy of the virus) is inserted into a computer, there is a good chance the virus will be copied to that computer. In particular, if that disk is in the drive when the computer is turned on, it will almost certainly load the virus into the machine. For that reason, you should never start up a computer with a floppy disk inserted. If you need to use the disk as a boot up disk (see below), then make sure that it has been checked with a virus checker and write protected (see above) so that the virus can not be copied to that disk. What the virus does when the "predetermined situation" occurs is limited only by the virus programmer's skills and imagination. At one extreme, a virus may simply make some kind of announcement on the screen of its presence, but at the other extreme, it could completely destroy all the files on the hard drive. The "presetermined situation" could be a specific date (according to the system clock), a certain number of floppies inserted or files copied, or any other type of countable or measurable activity. There are several anti-virus programs available ranging from commercial products such as Norton Anti-Virus to many shareware offerings. The best type of anti-virus software checks each time a floppy is inserted or a file is downloaded (such as Norton's).


Word Processor

A word processor is an application that allows you to enter text and then format in various ways such as adjusting margins, specifying certain fonts or font attributes (such as bold) or organizing text into columns and data into tables. Most word processors allow you to add graphics and provide Spelling and Thesaurus functions.

World Wide Web (WWW or 'web')

The best-known aspect of the Internet. The WWW presents data in the form of formatted text and graphics by specifying formatting using the HTML language and displaying it in a special program called a browser.

Write Protect

High density disks (of the 3.5" variety) have two square holes on one end. One hole has a plastic slider that can move to block light passing through the hole. This hole is the "Write Protect" feature. When the hole is blocked, it is possible to read data from the disk, but the user can not write or store any data on the disk.