AutoCAD
and Its Applications
B A S I C S
S t u d e n t We b S i t e
REFERENCE
M AT E R I A L S
Glossary of Computer Terms
A
Accelerator board: A graphics card designed to increase the speed and power
of the graphics processing duties of a computer. An accelerator board has its own
central processing unit (CPU) and relieves the computer’s CPU of some of the
processing work. Many industrial applications need high-end graphics accelerator
boards because of the complexity of the models, renderings, and animations.
B
Bitmap: An image consisting of rows and columns of dots, also known as a raster
image. The number of dots per square inch in a bitmap defines the resolution of the
image. A bitmap has no dimensional values. Many paint and draw programs create
bitmap images and files.
C
Card: A thin plate, commonly known as a board, on which a variety of electronic
chips are mounted. Also known as a printed circuit board, a card can be inserted
into a computer to perform a variety of functions, from increasing the power of the
computer’s graphics to running other peripheral devices.
CD-ROM (CD): A thin plastic optical disk that stores data and is read by a CDROM drive using a laser. The average CD holds about 700 megabytes (MB) of
information.
CD-ROM drive: A device used to play or read CD-ROMs.
Chip: A very small piece of silicon on which entire integrated electronic circuits
are embedded. Many different types of chips are used in computer applications.
Microprocessor chips run computers, while memory chips store working information
temporarily before it is saved to a storage device.
CPU: The abbreviation for central processing unit. The CPU is the heart of the
computer. In personal computers, it is a microprocessor chip that handles all the
system’s calculations.
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Glossary of Computer Terms, page 1
AutoCAD
and Its Applications
B A S I C S
S t u d e n t We b S i t e
REFERENCE
M AT E R I A L S
D
Digitizer tablet: An electronic drawing board used with some CAD workstations.
A plastic or paper menu overlay containing AutoCAD tools and drawing symbols
is commonly placed over the tablet. Items can be selected directly from the menu
using a puck or stylus without looking at the screen. Movement of the pointing
device is recorded and displayed on-screen as the cursor position.
Display device: See monitor.
F
Flash drive: A portable storage device.
Function keys: The individual keys on a keyboard labeled [F1] through [F12].
In AutoCAD, the function keys are used to activate tools and perform specific
operations that would otherwise have to be entered or selected using a pointing
device.
G
Graphics card: A board that controls graphics processing and the resolution of
the computer monitor. Accelerator cards can be inserted to allow the computer to
process graphics faster and with higher resolution.
H
Hard disk drive: A sealed unit containing one or more disks, or platters, used to read and
write computer data. Hard disks have a large storage capacity and are typically measured
in gigabytes (GB) or terabytes (TB). Common hard disk sizes are 40 GB to 4 TB.
Hardware: The physical pieces of computer equipment, such as the CPU, monitor,
keyboard, and printer or plotter.
K
Keyboard: An input device resembling a standard typewriter keyboard, with
additional keys located to the left, right, and top.
M
Monitor: A computer display output device resembling a small television. Common
monitor sizes are 17″, 19″, and 21″ (measured diagonally).
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Glossary of Computer Terms, page 2
AutoCAD
and Its Applications
B A S I C S
S t u d e n t We b S i t e
REFERENCE
M AT E R I A L S
Mouse: A computer input device used to select items, perform cursor movement,
and specify point locations on-screen. A mechanical mouse has a roller ball on the
bottom. The movement of the roller on any flat surface is sent to the computer and
displayed as the movement of the screen cursor. Unlike a stylus or puck, a mouse
can be lifted and moved to another position without affecting the location of the
screen cursor. An optical mouse uses a laser to detect the mouse’s movement on a
flat surface and indicates the cursor location on-screen.
N
Network: A group of several connected computers communicating with each other.
Complex networks may have hundreds of computers or terminals working from a
central computer called a server.
O
Optical drive: A disk drive that reads information from optical disks. Some optical
drives can read disks that store more than 4 GB of data. Optical drives provide
reliability without the cost or vulnerability of magnetic media. Some types of optical
disks can be rewritten with new data as required. They are also faster and more
reliable for backups than magnetic tape drives.
P
Page: A portion of the program or current drawing file kept in random access
memory (RAM) or sent to the hard disk for temporary storage.
Peripheral: A hardware device connected to the computer, such as a keyboard,
monitor, printer, plotter, digitizer, modem, or scanner.
Pixel: A value used to measure screen resolution. Pixel means “picture element.”
A pixel appears as a dot on-screen, but it is actually a tiny rectangle. The display
of a monitor is composed of horizontal rows and vertical columns of pixels. See
resolution.
Plotter: A device used to output paper and film drawings. A plotter uses felt-tip,
ballpoint, or wet-ink pens; ink-jets; or pencils to place lines on paper. A raster
plotter, such as an ink-jet plotter, prints an entire row of the image at a time as the
paper advances. A pen plotter constantly moves around the paper, drawing each
vector separately. The terms plotter and printer are often used interchangeably.
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Glossary of Computer Terms, page 3
AutoCAD
and Its Applications
B A S I C S
S t u d e n t We b S i t e
REFERENCE
M AT E R I A L S
Pointing device: An input device used to move the screen cursor, specify point
locations, and select tools. Items can be selected from the screen or a digitizer
tablet menu. Commonly used pointing devices include the mouse and trackball.
Less commonly, CAD systems may use a multi-button puck or a pen-shaped stylus.
The puck and stylus are used in conjunction with a digitizer.
Printer: An output device that receives images and text from a computer for
placement on paper. Some laser printers can output images with resolution up
to 2400 dots per inch (dpi), but most are in the 600–1200 dpi range. Some inkjet
printers can output images with resolution up to 720 dpi. The terms plotter and
printer are often used interchangeably.
Puck: A multi-button input device used with a digitizer tablet. A puck may have as
many as 16 buttons. A set of small crosshairs in the puck serves as the pick point
for this device. As the bottom surface of the puck slides on the digitizer surface,
the movement controls the position of the screen cursor. One of the puck buttons,
the pick button, is used to enter points and select tools from menus. All the other
buttons can be programmed to suit the user.
R
RAM: The abbreviation for random access memory. RAM is made up of a group
of data-holding chips. The term random access memory refers to the ability of
the computer to randomly store and search for data in this area of memory. The
chips are similar to empty storage boxes. When a software program is loaded, the
program files are placed into the computer’s RAM.
Resolution: The display quality of images on-screen. The resolution of an image
determines how smooth or jagged the text and objects appear. Resolution is
measured in pixels. A typical display resolution is 1280 × 1024, meaning the image
displays 1280 pixels, or dots, horizontally and 1024 dots vertically.
S
Serial port: A socket or connector where a peripheral device, such as a modem or
mouse, is plugged into the computer.
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Glossary of Computer Terms, page 4
AutoCAD
and Its Applications
B A S I C S
S t u d e n t We b S i t e
REFERENCE
M AT E R I A L S
Server: A central computer serving a network of computers or terminals. The hard
disk drives in the server are normally large-capacity drives. Servers need to store a
variety of software and still have plenty of space for the numerous files created by
computer users attached to the network. The network server can also store drawing
files that may be needed by users in order to complete new drawings.
Storage device: Any drive or peripheral device used to save computer files.
Common storage devices include flash drives, hard disk drives, and CD-ROM drives.
Storage medium: Any device used to store computer data, such as a flash drive,
hard disk, or CD-ROM.
Stylus: A pen-shaped pointing device used in conjunction with a digitizer tablet.
Swap file: A file containing the least-used portions, or pages, of a program on
the hard disk. Swap files are used to store data that is not currently being used in
physical memory. Pages stored in a swap file are held there until needed again.
T
Trackball: A pointing device that enables you to move the screen cursor by rolling
a ball. A trackball requires only the amount of table space needed for it to sit on (the
ball is the only part rotated). Most trackballs have two or three buttons, much like a
mouse.
V
Vector image: An image created and stored using a starting point, a length,
and a direction, or vector. AutoCAD produces vector images. Vector images are
independent of screen resolution and can be displayed or printed at the highest
resolution available.
Virtual memory: A memory system that uses a combination of RAM and hard disk
space. A virtual memory system keeps only the part of the program that is currently
being used in physical memory. If additional portions of the program are needed,
AutoCAD creates a page on the hard disk and writes the least-used portion of the
program to that page. See swap file.
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Glossary of Computer Terms, page 5