| A |
- access time
- The time it takes to locate and retrieve data
from memory, typically secondary memory.
- access
- The ability to read, write or execute files or directories.
Access privileges are established by the owner of a file or directory and determine what
other users may do with a directory or its contents.
- active window
- The current window. The window through which one
communicates with the programs or processes that are running. Typically one process can be
assigned to one window and a time. .
- address
- A name or number which points to a location of data in primary or secondary memory.
- aliasing
- In image generation, aliasing is the generation
of a false (alias) frequency along with the correct one when doing frequency sampling. For
images, this produces a jagged edge, or stair-step effect. See Antialiasing.
- alphanumeric
- Relating to numbers, letters, and punctuation marks.
- algorithm
- A specific set of instructions design to solve a specific
problem, such as an algorithm to find a maximum value or to sort data
in a particular way.
The term algorithm (pronounced AL-go-rith-um) is a procedure or formula for solving a
problem. The word derives from the name of the mathematician, Mohammed ibn-Musa
Al-Khowarizmi, who was part of the royal court in Baghdad and who lived from about 780 to
850. Al-Khowarizmi's work is the likely source for the word algebra as well.
A computer program can be viewed as an elaborate algorithm. In mathematics and computer
science, an algorithm usually means a small procedure that solves a recurrent problem.
- antialiasing
- Antialiasing is the smoothing of the image roughness caused
by aliasing. Methods include adjusting pixel positions or setting
pixel intensities so that there is a more gradual transition between the color of a line
and the background color.
- application program
- A program (software) that performs substantive tasks, such
as a word processing program, a database program, a spreadsheet
program or a CAD program. As distinct from operating system software or
utility programs. array
- A list or table of values which can be addressed as a single
variable.
- AI Artificial Intelligence.
- The ability of a machine to learn, to reason, to mimic human
capabilities.
- ASCII
- American Standard Code for Information Interchange. The most
often used coding system for characters (text).
- ASCII file
- A file whose contents is text, represented in ASCII form. A file without formatting instructions. Used to transfer
text from one application program, usually a word processing program, to another.
- AutoCAD
- An intermediate level CAD software
package, for generic drafting. The most often used CAD software. There
are many third party software packages which can be used together with AutoCAD to make it
discipline specific.
- assembly language
- A low-level language which is close to machine language.
- asynchronous
- The transmission of data at irregular
intervals. As opposed to synchronous.
- attribute
- 1. A element of data in a database . 2. In some programs, a descriptive or organizational
characteristic that can be assigned to a graphic element.
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| B |
- back-up copy
- A copy preserved, usually on a different medium, as
protection from loss or destruction of original data.
- BASIC
- An easy to learn programming language.
- batch file
- A command file or script file. A file which contains a list
of instructions to be carried out without interaction with the user.
- batch processing
- Execution of a batch file or files, without interaction with
a user. The grouping of processes (into a batch) for execution at one time.
- baud
- Commonly understood as "bits per second". A
measure of the rate at which electronic impulses can be transmitted over a phone line.
- beta test
- Hardware and software testing in a work environment. The
final stage of testing prior to public release.
- Bezier curve (bez ee-ay)
- A type of curves calculated mathematically that connects two
points to form a smooth, free-form curve or surface. Bezier curves require few points to
define a large number of shapes - thus the advantage over methods of defining curves, such
as bits or mathematical expressions.
- binary
- Referring to the base 2 system of mathematics.
- bit
- Binary digit.
- The smallest unit of information that a computer can process
or store. Based on binary mathematics, the value of a bit may be either 0 or 1 (zero or
one) and may represent the numbers 0 and 1, or true and false, or on and off, or black and
white.
- bit map, often written bitmap
- An ordered set of bits that control the pixels on the
display. Each bit controls one pixel. The contents of the bit map
are determined by the software. The bit map is stored in the screen
buffer, or video memory (VRAM).
A bit map does not
need to contain a bit of color-coded information for each pixel on
every row. It only needs to contain information indicating a new color as the display
scans along a row. Thus, an image with much solid color will tend to require a small bit
map.
Because a bit map uses a fixed or raster graphics
method of specifying an image, the image cannot be immediately rescaled by a user without
losing definition. A vector
graphics graphic image, however, is designed to be quickly rescaled. Typically, an
image is created using vector graphics and then, when the artist is satisifed with the
image, it is converted to (or saved as) a raster graphic file or bit map.
- bit depth
- The number of colors available on a system is determined by
the bit depth, which is the number of bits of information
used to represent a single pixel on the monitor. The lowest number of bits used for modern
desktop color monitors is
usually 8 bits (256 colors); 16 bits provide for thousands of colors (65,536, to be
exact); and 24 bits, common on
newer systems, provide for millions of colors (16,777,216). The specific colors available
on a system are determined
by the way in which the target platform allocates colors. Available colors might differ
from application to application.
(from Sun's web site)
- block
- A group of data (bits or bytes)
read in or written out in a single transaction. Many operating systems prefer to manage
blocks rather than single bytes. Blocks can be 512 or 1024 bytes.
- Boolean
- Pertaining to the algebra developed by the French
matematecian George Boole (1815-64).
- Boolean algebra
- Algebra similar in form to ordinary algebra, but with
classes and propositions for variables rather than data values. It
includes the operators AND, OR (inclusive or), XOR (exclusive or), NOT, EXCEPT, IF, and
THEN.
- Boolean variable
- Use of two valued Boolean algebra to either one of two
values possible. Examples would be true or false; on or off; open or closed.
- Boolean operations
- An operation in Boolean algebra performed on or with two
operands and in which the result is dependent upon both of them. Such operands are
typically represented with connective symbols
- Examples in CAD would be:
- AND (element A AND element B), also called a
"union" in which two graphic elements may be joined (unioned) to produce a new,
third, object.
NOT (element A BUT NOT B), also called a "subtraction" in which one graphic
element is subtracted from another to produce a new, third, element.
OR (element A OR B), also called a "split" in which two intersecting graphic
elements are split into three new graphic elements.
- boot (or reboot)
- Starting (or restarting) the computer system. The computer
performs an internal check of its systems, verifies the various peripheral devices that
may be attached and starts the operating system running.
- buffer
- An area of memory that is used to temporarily store
information. Many application programs establish buffers for data that
has been deleted, allowing the user to retrieve or transfer the data.
Many printers and plotters have memory, called a print buffer, that temporarily holds data sent from the computer while it waits to be printed relieving the
computer and its RAM.
- bug
- An error in a program or a computer system.
- bus
- The communication pathway within the computer system that
transmits data from one part of the system to another. The 'width' of
the bus is measured in bits, thus a 16 bit bus can
transmit 16 bits simultaneously. The speed of the bus is controlled by
the system's clock, measured in Hz.
- button
- An icon, or image, displayed on the monitor which resembles
a pushbutton. May be used to select (with the cursor) various actions.
- byte
- A unit if information, typically eight bits.
Can be used to represent one character or one number or one component of an image. Files
are often measured in bytes, kilobytes, megabytes,
gigabytes and terabytes.
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| C |
cache
- High speed RAM, closely associated with the CPU. Memory
cache holds data waiting to be processed by the CPU. Disk cache holds data waiting to be read to disk. It also stores information often called
from disk, such as a listing of files. Use of caching speeds the transfer of data.
- CAD
- Computer Aided Design. Sometimes used as Computer Assisted
Design. Sometimes used as Computer Aided Drafting.
- CADD
- Computer Aided Design and Drafting.
- CAI
- Computer Assisted Instruction.
- CAM
- Computer Aided Manufacture.
- cell
- In spreadsheet software, the intersection of one row and one
column. Used as an address for data.
- Central Processing Unit. or CPU
- See CPU.
- character
- One unit of alphanumeric data.
- close (a file)
- To close a file is to save a file, to copy the contents of
the file from primary memory (RAM) to secondary memory (usually disk). The process insert
a marker in the File Allocation Table (FAT) on the disk indicating that there is no more
to the file.
- cluster
- In personal computer storage technology, a cluster is the
logical unit of file storage on a hard disk; it's managed by the computer's operating
system. Any file stored on a hard disk takes up one or more clusters of storage. A file's
clusters can be scattered among different locations on the hard disk. The clusters
associated with a file are kept track of in the hard disk's file allocation table (FAT).
When you read a file, the entire file is obtained for you and you aren't aware of the
clusters it is stored in.
- Since a cluster is a logical rather than a physical unit
(it's not built into the hard disk itself), the size of a cluster can be varied. The
maximum number of clusters on a hard disk depends on the size of a FAT table entry.
Beginning with DOS 4.0, the FAT entries were 16 bits in length,
allowing for a maximum of 65,536 clusters. Beginning with the Windows 95 OSR2 service
release, a 32-bit FAT entry is supported, allowing an entry to address
enough clusters to support up to two terabytes of data (assuming the
hard disk is that large!).
- The tradeoff in cluster size is that even the smallest file
(and even a directory itself) takes up the entire cluster. Thus, a 10-byte
file will take up 2,048 bytes if that's the cluster size. In fact, many
operating systems set the cluster size default at 4,096 or 8,192 bytes.
Until the file allocation table support in Windows 95 OSR2, the largest size hard disk
that could be supported in a single partition was 512 megabytes. Larger hard disks could
be divided into up to four partitions, each with a FAT capable of supporting 512 megabytes
of clusters.
- COBOL
- COmmon Business Oriented Language, A high level programming
language used for business applications.
- color wheel
- A method of designating aspects of color, in particular hue.
Measured as if degrees on a 360 degree circle.
- color cube
- A method of representing colors, both additive and
subtractive, on a cube.
 - color, bits
- see bit depth
- command
- An instruction to a computer that triggers a process, which may be one or more instructions.
- compile
- The translation of a high (human) level programming language
program into a low (machine) level language program.
- console
- The component of the computer system (hardware) that is the
primary communication device between the user and the system.
- coprocessor
- A microprocessor or auxiliary processor optimized for a
specific type of operation, such as floating point mathematics, video processing or 3D data processing. Relieves load on the CPU.
- configuration
- 1. The relationship of the various physical parts of a
computer system. 2. The settings of the software which control the communication of the
hardware components for a computer system.
- core memory
- Primary memory (RAM). Originally primary
memory was magnetic and the direction of the magnetic field (clockwise or
counterclockwise) was used to represent zero or one.
- core dump
- The writing out (dumping) of the entire contents of primary
memory. In some systems in it written to a file named core . When analyzed by specialized
software it may indicate the nature of the problem. Usually indicates a serious problem.
- CPU
- Central Processing Unit. The hardware portion of a computer
system that does the actual computation. The power of the CPU is measured by the number of
bits it can process at one time (a 32 bit CPU can
process 32 bits with each tick of the clock) and the speed with which it can process the data which is controlled by the system clock (stated in kilohertz,
megahertz or gigahertz). The more bits a CPU can process and the faster
it can process them, the more powerful it is.
- CRT
- Cathode Ray Tube, the actual part of a display or monitor
that projects cathode rays onto the interior surface of the screen. Informal term for the
display or monitor. Erroneous term for an entire computer system.
- cursor
- A pointer on the display or monitor. Controlled by various
techniques, such as the control arrows on a keyboard, a mouse, a stylus or a puck.
- current default
- A value, typically set by the user. Once set it is
applied without the user's continuing interaction. As opposed to default.
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| D |
- data
- Representation of information, facts. data
can be numbers, characters or other types, such as graphic.
- database
- 1. A computer program (software) used to manipulate
information (data).
2. A form or format that is prepared to store and manipulate data.
3. The content, the data, the information stored or being manipulated.
The terms are often used interchangeably.
- database is a collection
of data that is organized so that its contents can easily be accessed,
managed, and updated. The most prevalent type of database is the
relational database, a tabular database in which data is defined so that it can be reorganized and accessed in a number of
different ways. A distributed database is one that can be dispersed or
replicated among different points in a network.
- debug
- Process of locating and correcting errors in software.
- default
- A value or setting that a computer system assumes. Such
values are typically set by the hardware or software designers. Some programs allow such
values to be changed by the user. See current default.
- degenerate polygon. Also
known as a warped polygon
- A polygon defined by four or more nodes (points) which are
not coplanar. Many CAD databases will permit such a polygon to be defined but they will
cause problems in rendering (casting shadows) and when executing Boolean operations which
require the calculation of intersections.
- digitize
- Process of converting data from analog
form to digital form.
- digitizing tablet
- A data input device. A surface (tablet)
together with a pointing device (a mouse, puck or stylus) that is used to draw or trace
images which converts the information into digital form.
- directory
- A special type of file, able to contain files or names of
files or other directories. Used as an organization strategy.
- display
- Display device, screen, monitor. A device for displaying
text and graphic images.
- display list
- A sorted list of graphic elements to be sent to the screen,
typically sorted beginning with the element farthest from the eye point and
concluding with the element closest to the eye point. When sent to the screen and
displayed in this order, the resultant image can appear to have the properties of a three
dimensional object.
- diskette
- One form of secondary memory. data
storage media. A 3 1/2" or 5 1/4" plastic disk capable of storing data in magnetic form. Also called floppy disk.
- disk drive
- One form of secondary memory. A data
storage device. data can be read to and written from a disk drive.
Access times are slower than RAM but much faster than diskette. The cost per bit of data is less than RAM and less that diskette. data is stored in magnetic form which is non-volatile (not effected by a
power supply).
- DOS
- Disk Operating System. The housekeeper. A program (software)
which controls many of the computers functions, including the management of files on disk
or diskette.
- DRAM
- Dynamic Random Access Memory. Another name for RAM. Dynamic
refers to its volatility, the loss of it contents when electricity is turned off.
- driver
- A program (software) that controls (drives) a peripheral
device, such as a plotter or printer. Must be specific to the peripheral device.
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| E |
- Encapsulated PostScript
- (EPS) An extension of the PostScript graphics file format
developed by Adobe Systems. EPS is used for PostScript graphics files that are to be
incorporated into other documents. An EPS file includes pragmas (special PostScript
comments) giving information such as the bounding box, page number and fonts used.
- On some computers, EPS files include a low resolution
version of the PostScript image. On the Macintosh this is in PICT format, while on the IBM
PC it is in TIFF or Microsoft Windows metafile format.
- E-mail or email
- Electronic mail. An application which replicates components
of a mail system. Allows users to prepare messages, send messages or files, receive
messages or files.
- EPROM
- Erasable Programmable Read Only Memory. Permanent memory
within the computer that can be erased and programmed with special equipment.
- Ethernet
- A commonly used high-speed network.
- expansion card
- A component of hardware, a circuit board that can be added
(inserted) into the computer system to provide additional capabilities, such as increased
memory, networking, printer control or display control. Allows a computer system's
configuration to be modified.
- expert system
- A knowledge-based system within artificial intelligence. One
which seeks to mimic the knowledge of an expert in an interactive setting.
- extension
- An addition to a file's name, used to indicated the type of
file, such as text, graphic, or program. Usually assigned by an application program.
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| F |
- facilities management
- An application program which allows users to describe,
store, and manipulate information relating to buildings, such as room occupancies or use,
furniture, maintenance of systems, etc. facsimile Ability to electronically transmit and
receive copies of documents. FAX for short.
- FAT
- File Allocation Table. A table that is established at the
beginning of each disk (hard or otherwise) during formatting. The FAT maintains the
information regarding filenames and the physical address on the disk of all of the data
A file allocation table (FAT) is a table that an operating system maintains on a hard disk
that provides a map of the clusters (the basic units of logical storage on a hard disk)
that a file has been stored in. When you write a new file to a hard disk, the file is
stored in one or more clusters that are not necessarily next to each other; they may be
rather widely scattered over the disk. A typical cluster size is 2,048 bytes,
4,096 bytes, or 8,192 bytes. The operating system
creates a FAT entry for the new file that records where each cluster is located and their
sequential order. When you read a file, the operating system reassembles the file from
clusters and places it as an entire file where you want to read it. For example, if this
is a long Web page, it may very well be stored on more than one cluster on your hard disk.
Until Windows 95 OSR2 (OEM Release 2), DOS and Windows file allocation table entries were
16 bits in length, limiting hard disk size to 128 megabytes, assuming a
2,048 size cluster. Up to 512 megabyte support is possible assuming a cluster size of
8,192 but at the cost of using clusters inefficiently. DOS 5.0 and later versions provide
for support of hard disks up to two gigabytes with the 16-bit FAT entry
limit by supporting separate FATs for up to four partitions.
With 32-bit FAT entry (FAT32) support in Windows 95 OSR2, the largest
size hard disk that can be supported is two terabytes.
- field
- A data element in a database.
- file
- A named, ordered set of data, stored in
secondary memory, with a unique address (name). Files may contain data
(text, numbers, binary data representing graphic information) or
programs (sets of instructions to be executed) connected to the file name. The actual
content of the file may be distributed throughout a disk, but its physical location
(address) is maintained in the File Allocation Table.
- File Transfer Protocol
- File Transfer Protocol (FTP), a standard Internet protocol,
is the simplest way to exchange files between computers on the Internet. Like the
Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related
files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an
application protocol that uses the Internet's TCP/IP
protocols. FTP is commonly used to transfer Web page files from their creator to the
computer that acts as their server for everyone on the Internet. It's
also commonly used to download programs and other files to your computer from other
servers.
- As a user, you can use FTP with a simple command line
interface (for example, from the Windows MS-DOS Prompt window) or with a commercial
program that offers a graphical user interface. Your Web browser can also make FTP
requests to download programs you select from a Web page. Using FTP, you can also update
(delete, rename, move, and copy) files at a server. You need to logon to an FTP server.
However, publicly available files are easily accessed using anonymous FTP.
- Basic FTP support is usually provided as part of a suite of
programs that come with TCP/IP. However, any FTP client program with a graphical user
interface usually must be downloaded from the company that makes it.
- From Whatis.com
- fixed disk
- Another term for hard disk.
- flat file
- A database structure with a single
table. The simplest form of database.
- flops
- FLOating Point operations per Second. The speed with which a
CPU can perform mathematical operations that involve real numbers. A measure of the speed
of a CPU.
- format
- The arrangement (form) of something, typically the data in a file. ASCII, DXF, TIFF, IGES are examples
of file formats.
- format (disk)
- A process which prepares a disk or diskette to accept data. The operating system controls the formatting process. Different
disks and different computer systems require different formats. Produces a blank but
usable disk.
- FORTRAN
- FORmula TRANslator. A high level programming language used
for scientific applications.
- frame
- 1. In film and video recording and playback, a frame is a
single image in a sequence of images that are recorded and played back. 2. In computer
video display technology, a frame is the image that is sent to the display image rendering
devices. It is continuously updated or refreshed from a frame buffer, a highly
accessible part of video RAM.
- frame buffer
- Another term for VRAM, Video Random Access Memory. Stores
the bit which controls the display. Same as screen buffer.
- FTP
- See File Transfer
Protocol.
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| G |
- gigabyte
- Approximately one billion bytes (2 to the
30 = 1,073,741,824).
- gif
- A graphics file format. Includes gif89a. Often pronounced
with a hard g although the original and (for some at least) preferred pronunciation is
JIF. Stands for Graphics Interchange Format which, together with GIF, are service marks of
CompuServe Incorporated. GIF is a file compression algorithm which is intended to be a
"non-lossy" process, meaning no loss of image data. It is
ideal for black and white images, in particular line drawings. Images with tonal range,
such as photographs, are better compressed in jpeg format. The
compression is to allow faster transmission of image files across the internet. Thus a gif
file format is used when the image to be placed on a web page.
On the Web and elsewhere on the Internet the GIF has become a de facto standard form of
image. The LZW compression algorithm used in the GIF format is
owned by Unisys.
The GIF uses the 2D raster data type and is encoded in binary. There
are two versions of the format, 87a and GIF89a. Version 89a (July, 1989) allows for the
possibility of an animated GIF, which is a short sequence of images within a single GIF
file. A GIF89a can also be specified for interlaced GIF presentation.
A patent-free replacement for the GIF, the Portable Network Graphics (PNG) format, has
been developed by an Internet committee and major browsers support it or soon will.
From Whatis.techtarget.com
- GIGO
- Garbage In, Garbage Out.
- graphic element
- a. data that can be displayed as a
graphic image (as opposed to characters or numbers).
b. data that can be treated as a single entity.
c. Whatever a CAD program declares to be a graphic element.
- group
- In UNIX operating systems, user access privileges may be set
for the owner of the file, members of a group and all users of the system. All users are
members of a group. The specific group is determined by the system administrator.
- GUI
- Graphical User Interface. A program (software) that permits
display and control of computer functions by graphic means, as opposed to control by
commands typed at a keyboard.
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| H |
- hard drive
- A data storage device, used for mass
memory, the storage of large quantities of data. It is made of spun
aluminum and is permanently sealed in a housing. Faster and cheaper (per unit of data) than diskette, slower and cheaper than RAM. Non volatile and non
portable. data is stored in magnetic form which is permanent.
- hard disk
- Another term for hard disk.
- hardware
- The physical, tangible portion of a computer system,
including the CPU, display devices, storage devices, output devices, etc. As opposed to
software.
- hertz
- One cycle per second. Used to measure CPU speed and monitor
refresh rates.
- host, host computer
- The processor which controls an entire computer system.
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| I |
- I/O
- Input/Output.
- IC, IC board
- see integrated circuit.
- icon
- A pictorial or graphic representation of something, usually
a file, a window, or a button.
- initialize
- To prepare or to begin. Some programs, such as X windows,
are started by an initialization command.
- input
- data submitted to the computer from an
input device for processing or storing. See also Output.
- integrated circuit
- An electronic circuit that is contained within a single
piece of semiconductor material, typically silicon.
- intelligent terminal
- A terminal with computing capabilities, with a CPU.
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| J |
- jpeg, jpg
- Stands for Joint Photographic Experts Group (pronounced
JAY-peg). The original name of the committee that designed a standard image compression algorithm. JPEG is designed for compressing either full-color or
gray-scale digital images that have a range of tonal or color values. It is not ideal for
line drawings. JPEG does not handle compression of black-and-white (1 bit-per-pixel)
images or moving pictures. The amount of compression can be determined by the maker of the
image. The process is called a "lossy" process because some of the detail is
removed in the compression process. jpeg files are typically intended for use on web pages
since the smaller file size that results speeds transmission of the image across the
internet. The software that displays the image (the browser) must be able to uncompress
the data. The greater the degree of compression, the greater the loss
of data. The most common standard for compressing movies are known as
MPEG.
- Together with the Graphic Interchange Format (GIF)
and Portable Network Graphics (PNG)
file formats, the JPEG is one of the image file formats supported on the World Wide Web,
usually with the file suffix of ".jpg". You can create a progressive JPEG
that is similar to an interlaced GIF.
From Whatis.techtarget.com |
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| K |
- keyboard
- An input device with keys which allows typing data for input.
- keyframe
- In animation, a critical (key) point of view (frame) set by
the user. The software interpolates the intervening views (frames) prior to rendering each
frame.
- kilobyte (KB or kb)
- Approximately 1,000 bytes (2 to the 10 =
1024 bytes). See also byte, megabyte, gigabyte,
terabyte.
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| L |
- language
- A highly ordered set of instruction which possess aspects of
human language, particularly syntax (grammar) and vocabulary.
- LAN
- Local Area Network. A system which interconnects device in a
limited area, a room.
- LISP
- LISt Processing. A high level programming language. Used in
artificial intelligence.
- load
- To open a file, to copy the data from
disk to RAM. Note that it is a copying process.
- loft curve
- A curve which passes through its control points, as opposed
to a Bezier curve.
- logical operator
- Allows information to manipulated using principles of formal
logic, in particular the AND, inclusive OR, exclusive OR, NOT comparisons.
- loop
- A set of instructions in a program that are repeated.
- lossless and lossy compression
- Lossless and lossy compression are terms that describe
whether or not, in the compression of a file, all original data can be
recovered when the file is uncompressed. With lossless compression, every single bit of data that was originally in the file remains
after the file is uncompressed. All of the information is completely restored. This is
generally the technique of choice for text or spreadsheet files, where losing words or
financial data could pose a problem. The Graphics Interchange File
(GIF) is an image format used on the Web that provides lossless compression.
- On the other hand, lossy compression reduces a file by
permanently eliminating certain information, especially redundant information. When the
file is uncompressed, only a part of the original information is still there (although the
user may not notice it). Lossy compression is generally used for video and sound, where a
certain amount of information loss will not be detected by most users. The JPEG image
file, commonly used for photographs and other complex still images on the Web, is an image
that has lossy compression. Using JPEG compression, the creator can decide how much loss
to introduce and make a trade-off between file size and image quality.
- low-level language
- A computer programming language that is specific of a
particular CPU. As opposed to a high (human) level language.
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| M |
- main memory
- Another term for RAM, or random access memory. Often called
system memory or working memory.
- megabyte (MB or mb)
- Approximately 1 million bytes (2 to the
20 = 1,048,576 ). See also kilobyte, gigabyte.
- memory
- The hardware portion of a computer system that stores
information. See also main memory, system memory, working memory, and RAM.
- menu
- A list of options displayed on the screen from which the
user may select. The cursor may be moved over the menu items (usually with a mouse) for
selection.
- MHz
- Megahertz. One million hertz.
- microfloppy
- A 3 1/2" plastic disk for data
storage. Made of rigid plastic in a rigid plastic sleeve.
- microprocessor
- A CPU on a single silicon chip. As opposed to a multi chip
CPU.
- minifloppy
- A 5 1/4" plastic disk for data
storage. Made of somewhat flexible (thus floppy) plastic in a soft plastic sleeve.
- MIPS
- Million Instructions Per Second. The speed with which a CPU
can procession instructions. A measure of the power of a CPU.
- mirror
- The process of mirroring or reflecting a graphic element
about an axis of symmetry. The mathematical process is one of multiplication by minus one,
a process of negation.
- modem
- MOdulate-DEModulate, or MOdulator-DEModulator. An input and
output device which permits computers to communicate over ordinary telephone lines.
Converts internal computer system communications, which are typically parallel, to serial
form.
- modem port
- A connector or socket. If the modem is internal (within the
system box) it is the connector to which the telephone is connected. If the modem is
external (outside the system box) it is the connector to which the modem is connected.
- Modula-2
- A high-level computer programming language. Noted for its
self contained subdivisions which can be combined to form a new program.
- monitor
- An output device for display of test or graphic information.
Uses cathode ray (raster) technology, similar to a television screen. Also called display,
CRT or screen.
- motherboard
- Computer circuit board that contains the CPU, memory chips, I/O controlling chips and main communication bus.
- mouse
- An input device. A hand held device that is moved across a
table surface which controls the movement of the cursor.
- MS-DOS
- Microsoft - Disk Operating System. Same as DOS or PC-DOS The
most common operating system for IBM PCs and compatibles. Developed by Microsoft
Corporation .
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| N |
- nanosecond
- One billionth of a second.
- network
- An interconnected system of computers and peripheral
devices. The term often refers to the system of wires and related hardware and software
which provide the interconnection itself. Permits communication and sharing of devices, data and computer resources.
- numeric
- Having to do with numbers, from 0 to 9. Compare to alpha.
- NURBS
- Non-Uniform Rational B-Spline, a mathematical representation
of a 3-dimensional object. Most CAD applications support NURBS, which can be used to
represent analytic shapes, such as cones, as well as free-form shapes.
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| O |
- on-line
- data that is accessible or hardware that
is controlled.
- open
- To open a file is to load a file, to copy the contents of
the file from disk to RAM. Renders the contents of a file accessible.
- operating System
- The program (software) that controls the internal workings
of the computer system together with its peripheral devices. Performs basic housekeeping
tasks, including interference checking (traffic control), passing data
to and from devices and managing data in memory.
- output
- data that is produced by processes. The
result of processing data. data transferred from
the CPU to another external device, such as the monitor, disk, printer, etc. As opposed to
input.
- owner
- The name of the user with access privileges to certain files
and directories. The owner of a file or directory may establish the access privileges for
the group and for all others on the system.
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| P |
- page
- 1.A portion of a program that is loaded into main memory
when needed; a process called paging or swapping.
2. One screen of information, or one window of information (similar to one page of a
document).
- page space
- An amount of hard disk reserved for swapping or paging
portions of a program, used as an extension of RAM. Moving portions of a program from hard
disk to RAM.
- parallel computer
- A computer with more than one CPU, thus able to process more
than one instruction at a time. A coarse grained parallel computer has few but powerful
CPUs (2 to 16) while a fine grained, or massively parallel, computer has many, but less
powerful, processors (up to 64,000).
- parallel port
- A connector or socket on the computer, capable of passing
electronic data in parallel fashion, for example, 16 bits
at a time. As opposed to serial port which can only pass data one bit at a time.
- parallel processing
- In a parallel computer, the process of dividing a task into
subtask and assigning them to various processors.
- parametric model, parametric modelling
- Any of a set of physical properties whose values determine
the characteristics or behavior of something. In CAD, 2D and 3D objects can be stored in a
database by its type together with a set of parameters. The parameters can later be edited
without having to recreate the object.
- parsing
- The process of systematically analyzing and translating a
command line prior to submission to the CPU.
- partition
- In personal computers, a partition is a logical division of
a hard disk created so that you can have different operating systems on the same hard disk
or to create the appearance of having separate hard drives for file management, multiple
users, or other purposes. A partition is created when you format the hard disk.
Typically, a one-partition hard disk is labeled the "C:" drive ("A:"
and "B:" are typically reserved for diskette drives). A two-partition hard drive
would typically contain "C:" and "D:" drives. (CD-ROM drives typically
are assigned the last letter in whatever sequence of letters have been used as a result of
hard disk formatting, or typically with a two-partition, the "E:" drive.)
- When you boot an operating system into your computer, a
critical part of the process is to give control to the first sector on your hard disk. It
includes a partition table that defines how many partitions the hard disk is formatted
into, the size of each, and the address where each partition begins. This sector also
contains a program that reads in the boot sector for the operating system and gives it
control so that the rest of the operating system can be loaded into random access memory.
- Boot viruses can put the wrong information in the partition
sector so that your operating system can't be located. For this reason, you should have a
back-up version of your partition sector on a diskette known as a bootable floppy.
- Pascal
- A high level procedure oriented programming language.
- password
- A unique word or string of characters, initially established
by the system administrator but changeable by the user. A means of validating that a
prospective user has appropriate access and system usage privileges. A security mechanism.
- path
- The logical route the operating system must follow through
directories and subdirectories to reach a specific file.
- peripheral device
- A component of hardware used together with and controlled by
the computer. Typically input and output devices such as printers, monitors, modems,
keyboards, etc.
- PC Personal Computer.
- Generically any personal computer. More specifically one
develop by IBM Corporation or one which is compatible to it.
- PC-DOS
- Personal Computer Disk Operating System. Same as DOS and
MS-DOS. The operating system for IBM PCs and compatibles, developed by Microsoft
Corporation and marketed by IBM Corporation.
- Personal Computer
- PC. A computer system which is single user and single
tasking.
- pipe
- An operating system term, in both DOS and UNIX, which
redirects the output of one process to become the input of another.
- pixel
- A PIcture ELement. The smallest dot that the computer's
monitor can display. On a black and white monitor, one pixel is controlled by one bit. Therefore there is a correspondence between the location of a bit in the bit map and the location of a pixel on the
screen.
- PL/1
- Programming Language 1. A high level procedure oriented
programming language.
- pointer
- 1.) another term for the cursor; 2.) an i-node or link
between two files constitutes a pointer from one file to another.
- polygon:
- The union of several line segments that are joined
together so as to completely enclose an area.
- port
- A connector or socket on the computer where cables can be
connected, used to connect peripherals. See also serial port and parallel port.
- plotter
- An output device, used to draw (plot) graphic images.
Various technologies include pen, electrostatic, laser, thermal and ink jet.
- primary storage, memory
- RAM. Another term for main memory, memory. As opposed to
secondary memory (hard disk or tape).
- printer
- An output device, typically for smaller sheet sizes (8 1/2 x
11 or A size) with text. Many printers are also capable of printing graphic images.
Various technologies include dot matrix, laser and ink jet.
- printer port
- The connector on the computer to which the printer is
connected.
- privilege
- The ability to control access to files and directories.
Privileges include the ability to read from, write to and execute a file.
- process
- In software, a transaction, an act which transforms data in some way. Requires input and produces output.
- processor
- Typically, the Central Processing Unit (CPU). In fact, any
component of the computer's hardware that calculates or computes. In personal computers,
the processor is small, a microprocessor, and is made of an integrated circuit on a single
chip. In workstations or larger systems, more than one processor may be used. A processor
may also be dedicated to a specific function, such as controlling the display aspects (a
video processor) or the plotter. Thus, modern computer systems have many processors.
- program
- A set of instructions. Controls various actions of the
computers resources and manipulates data to perform useful tasks.
Computer programs are also referred to, collectively, as software. A program may be
written by a user or may be professionally written and purchased. Programs must comply
with specific conventions governing their syntax and semantic content, thus forming
programming languages.
- program register
- A type or memory which stores the address (a pointer to the
location) of the next instruction to be processed.
- prolog
- A programming language used in artificial intelligence
applications.
- PROM
- Programmable Read Only Memory. Read Only Memory which the
user can load programs and data.
- prompt
- A message or symbol, generated by a program, which indicates
that the program is ready to receive instruction, or which leads the user to respond in
particular way.
- protocol
- Rules which control the way data are
transmitted.
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| R |
- RAM
- Random Access Memory. data storage
device. RAM is fast (data can be read to or written from RAM quicker
than any other storage media) but is expensive (per unit of data). RAM
is volatile (requires continuous flow of electricity, thus data is
lost if electric power is cut off).
- range
- A group of cells or data, defined by a
starting and ending number or identifier..
- raster
Also see frame,
raster graphics, and raster image processor.
The term raster refers to the region of a cathode ray tube (CRT)
or liquid crystal display (LCD) monitor that is capable of rendering images.
In a CRT, the raster is a sequence of horizontal lines that are scanned
rapidly with an electron beam from left to right and top to bottom, in much the same way
as a TV picture tube is scanned. However, there are certain differences. In general, the
resolution is better in a computer CRT than in a TV picture tube. Also,
a TV raster scan is interlaced, while the raster scan in a computer CRT
is almost always non-interlaced. In a CRT, the raster is slightly
smaller than the full screen size of the monitor. The height and width of the raster can
be adjusted, as can the horizontal and vertical position.
In an LCD, the raster (usually called a grid) is scanned differently than in a CRT; image elements are displayed individually. The raster normally
matches the screen monitor in size. But if low resolution is used (for example, 640x480
pixels on an LCD intended for 800x600), the displayed image may fill only part of the
screen. If high resolution is used (such as 1024x768 pixels on an LCD intended for
800x600), the displayed image may exceed the area of the screen, and scrolling will be
necessary to view all portions of the raster.
- raster graphics
- Raster graphics are digital images created or captured (for
example, by scanner in a photo) as a set of samples of a given space. A raster is a
grid of x and y coordinates on a display space. (And for three-dimensional images, a z
coordinate.) A raster image file identifies which of these coordinates to illuminate in
monochrome or color values. The raster file is sometimes referred to as a bit because it contains information that is directly mapped to the
display grid.
- A raster file is usually larger than a vector graphics image
file. A raster file is usually difficult to modify without loss of information, although
there are software tools that can convert a raster file into a vector file for refinement
and changes. Examples of raster image file types are: BMP, TIFF, GIF, and JPEG files.
- raster image processor
- RIP is also an abbreviation for Routing Information
Protocol.
A raster image processor (RIP) is a hardware or combination hardware/software product that
converts images described in the form of vector graphics statements into raster graphics
images or bits. For example, laser printers use RIPs to convert
images that arrive in vector form (for example, text in a specified font) into rasterized
and therefore printable form.
RIPs are also used to enlarge images for printing. They use special algorithms (such as error diffusion and schochastic)
to provide large blow-ups without loss of clarity.
- read
- Process of copying from secondary storage (hard disk or
tape) to RAM.
- recursion
- Refers to the ability of a computer program to refer to
itself, thus repeating a set of instructions.
- refresh rate
- The number of times per second that the cathode ray tube (CRT) fires at each pixel. Measured in hertz (Hz), times per second. Rates
below 60Hz will produce a noticeable flicker. Higher rates indicate a more stable image on
the display.
- register
- A portion of high speed memory where data
regarding the execution of an instruction are stored.
- relational data base
- A form of data base with multiple linked
tables.
- relational operators
- In formal logic, operators which express the relationship
between two expression, equal to, less than, greater than, less than or equal to, greater
than or equal to, not equal to.
- resolution
- A measure of the precision of a monitor. The number of
pixels. Usually stated as number across the screen by number of scan lines down the
screen. Example: 1024x768.
- RGB
- Red Green Blue. The three colors used in most display
devices (monitors). Requires three color values or signals to display any color.
- ROM
- Read Only Memory. Permanent memory within the computer (not
lost when electric power is turned off). Cannot be changed, only read. ROM stores the sets
of instruction that direct the computer when is first powered on. Compare to RAM.
- root directory
- The top or highest level directory.
- run
- The execution of a program.
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