Glossary of
Computer-Related Terms
A
B
Beta
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.
Bit
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.
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.)
Browser
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.
Bus
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.
Byte
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 "+".
C
Cache
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.
CPU
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).
CD-ROM
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.
Clipboard
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.)
CMOS
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.
Cursor
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.
D
Database
An organized collection of data such
as a mailing list, school grades or a company inventory.
Data
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.
Disk
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.
Drives
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.
Drivers
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.
DVD
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.
E
F
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.)
Font
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:
|
Serif
T J S
|
Sans Serif
T J S
|
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).
G
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.
Gigabyte
Approximately 1,000,000,000 bytes.
Modern computers come with hard drives of 10 gigabyte or larger in size.
H
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 10 gigabyte and go up to 120 gigabytes
or more. A 10 "gig" drive costs less than $200. 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).
I
Internet
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').
J
Joystick
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.
K
Kilobyte
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.
L
M
Megabyte
Approximately 1,000,000 bytes. Computer
memory is currently measured in megabytes. Modern computers usually
have 64 or more megabytes of memory.
Megahertz
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 IV CPU's run at 1000, 1400, 1700,
2000 and higher megahertz.
Modem
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.
Monitor
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.
Motherboard
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.)
Mouse
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).
MPEG
(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.
N
O
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.
P
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).
Printer
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.
Program
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.
Q
R
RAM
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.
ROM
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.
S
Scanner
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.
Spreadsheet
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.
SVGA
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.
T
Tape
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.
Trackball
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.
U
USB
An external bus that supports Plug
and Play installation. Using USB, you can connect and disconnect devices
without shutting down or restarting your computer. You can use a single
USB port to connect up to 127 peripheral devices, including speakers,
telephones, CD-ROM drives, joysticks, tape drives, keyboards, scanners,
and cameras. A USB port is usually located on the back of your computer
near the serial port or parallel port. Universal serial bus is also
called USB.
V
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.
VGA
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.)
Virus
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).
W
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.
X
Y
Z
|
