Accelerated Graphics Port: a type of expansion slot that can be found on most new motherboards.
AGP slots have a higher bandwidth than either PCI or ISA, making them suitable for high-performance video cards.
bandwidth
A relative measure of how much data can pass through a certain connection during a given amount of time.
BIOS
A special piece of software built into the motherboard of most computers that
contains the basic processes executed when starting up. It is stored in
memory that is not erased when the power is turned off. This is usually read-only
memory (ROM), but newer computers use re-programmable "flash" ROM.
bit
A 1 or a 0 (short for "binary digit").
boot
The process that occurs upon starting up a computer in which the BIOS is implemented, hardware is recognized, and the operating system is initiated.
The amount of data used to store the color of each pixel on the screen.
Color depth is usually measured in bits per pixel or BPP.
Common color depths in Windows are 8, 16, 24, and 32 BPP.
controller
A hardware component that allows the installation of other hardware devices of a certain hardware interface
by controlling the flow of data between these devices and the rest of the
computer. A controller also allows software programs to communicate with
these devices. Controllers usually come in the form of PCI
and ISA cards. Examples are IDE controllers and
SCSI controllers.
CPU
Central Processing Unit: a component that resides on the motherboard and carries out logic operations to manipulate memory and control hardware.
The CPU can be considered the "brain" of the computer because it controls nearly everything.
daisychain
A way of connecting many devices to a computer
which reside outside of the computer's case. The devices are connected to each other
in one chain using cables. One device connects directly to computer, another device
connects to that first device, a third device connects to that second device, and so on.
Daisychaining helps to reduce the clutter of cables behind the computer, and
allows for more space flexibility when setting up a computer and computer furniture in a room.
SCSI devices and parallel port devices connect to the computer and to each other
using daisychaining.
device
A computer component that is designed to perform a specific task not
essential to the operation of the computer itself.
DIMM
Dual In-line Memory Module: a circuit board upon which RAM resides.
DIMMs have a 64-bit data path and can be used alone, unlike SIMMs which must be installed in pairs.
The distance between adjacent pixels on a screen, usually measured in millimeters.
drive
A medium on which data can be physically stored (usually magnetically) and remain after the computer is powered down
or the medium is removed from the computer so that the data can be accessed later. In most
examples (such as hard drives, floppy drives, and removable cartridge drives),
data can be freely stored and removed as long as the drive is in
functioning condition and is not locked. In other examples (such as CD-ROM drives),
the data is stored permanently when the drive is initially created and
cannot be altered later on.
The term "drive" can also refer to a device used to accommodate a particular
removable data-storage medium (such as a CD-ROM drive, which can read CD-ROMs). In
this case, the media are usually referred to as "disks."
driver
A piece of software that allows a hardware component and another piece of
software to communicate back and forth. Drivers are usually written by
hardware manufacturers. Most drivers are written to allow a hardware component
and Windows 9x to communicate, allowing any Windows application to communicate with
the component indirectly.
The term "driver" has an expanded definition when used in conjunction with scanners.
In addition to the meaning already stated, it means a software application that the
user interacts with to control the operation of the scanner when importing an image.
expansion slot
A slot on the motherboard to which certain hardware devices, such as sound cards and video cards, can be attached.
Expansion slots currently come with AGP, PCI, or ISA interface.
file
The basic unit of data storage. All data stored on a drive
must be stored as one or more files.
floppy drive
The most common type of removable drive.
Floppy disks can store either
1.44 megabytes or 1.2 megabytes of data, and are 3.5 or 5.25 inches square in size,
respectively. Data can be read from, written to, or removed from floppy disks.
gigabyte
Approximately one billion bytes, or approximately
one thousand megabytes.
A drive that is installed in the computer in a relatively permanent fashion
and that cannot be expanded in capacity or readily exchanged with another computer.
Compared to removable drives, the hard drive allows for the fastest access to data;
therefore, the computer's most critical data (such as the files that make up the
operating system) are usually stored on the hard drive.
IDE
Integrated Drive Electronics: a hardware interface that is found in most
personal computers. A controller
is attached directly to each device, instead of one controller governing
several devices, allowing each device to be attached
directly to the motherboard for faster data-transfer rates. IDE devices are
usually not as fast as their SCSI counterparts.
ISA
A type of slot similar to PCI, but older, more ubiquitous, and less capable
of transferring large amounts of data quickly. ISA slots are longer than PCI slots.
Unlike PCI devices, ISA devices each require IRQ settings; therefore, the
installation of ISA components is often more complicated. Examples of ISA devices
are sound cards, modems, and controller cards.
IRQ
Interrupt Request: special number designations assigned to certain hardware
devices that allow the devices to share the CPU's "attention". The
numbers are set by setting jumpers or wires on each such device. No two
devices can share an IRQ number.
jumper
A small plastic block with a metal contact that is used to connect two metal pins.
keyboard
A set of buttons that allows the user to control
the computer or enter data. The keyboard is an essential input component
without which most computers will not fully start up when turned on.
That in which data can be electronically stored. Data stored in memory
is usually not organized logically into files as is data stored on drives;
rather, it is organized and managed directly by a piece of software. The
most common type of memory, RAM, can only store
data temporarily while the computer is turned on, but other types, such
as that built onto many pieces of hardware to store programming, can store
data permanently.
modem
A device used to convert digital data into analog waves for transmission over phone
lines, and vice versa. Modems allow two computers to communicate with each other
in order to perform tasks such as transferring files and accessing bulletin board
services. Most modems either attach to the computer externally via a serial port,
or are installed internally in an ISA
slot.
motherboard
The board to which the computer's most critical components (CPU, RAM, and
ISA and PCI slots) are directly attached and to which all of the computer's
components must be in some way attached. The motherboard contains all of
the computer's vital and underlying circuitry.
network
A group of computers linked together in order to easily share data and
resources.
OCR
Optical Character Recognition: the process that occurs when a scanned text document
is converted from an image to an editable text or word-processing file.
parallel port
A type of port designed for printers that is also used for peripherals such
as removable cartridge disk drives and scanners. Most allow transfer rates of
approximately 1.25 megabits per second.
PCI
A type of slot built in to the motherboard that is designed to capacitate card-based
components that must transfer relatively large amounts of data quickly for processing.
Examples of PCI components are graphics adapters, network adapters, SCSI adapters,
and in some cases, sound cards.
pixel
The smallest unit of color on a screen.
The image displayed on a monitor is made up of thousands of pixels, each capable of displaying different colors depending on the color depth.
pointing device
An input device that allows for the free planar movement of an on-screen icon, usually
an arrow. The user can trigger events by placing the icon over a region on
the display and pushing one of the device's buttons (termed "clicking").
Pointing devices allow the user to control the operation of the computer
and applications.
port
A fixture that allows for the transfer of data between computer components
through a conduit, when one of the components is located outside of the computer
case. It is usually a place for a cable of some sort to be attached.
PS/2
Personal System 2: an input device interface standardized by IBM usually used with mice or keyboards.
RAM
Random Access Memory: That in which the operating system physically stores data temporarily.
Data are stored in the RAM of a computer because they can be accessed much faster
than from any drive. The operating system will usually store in the RAM the most
often accessed data and programs that are running.
A type of drive that is designed to accommodate
and read data from specific media (disks) which can be removed and used with other
computers. Many removable drives are also able to write data to and remove data from disks.
removable cartridge drive
A type of removable drive that uses
disks generally rectangular in shape;
the part of the disk on which data are stored and from which data are read is
usually a single piece of a relatively solid material.
There are many different kinds and makes of removable cartridge
drives, and almost none is compatible with a type of disk different from the one specifically
designed for it. Removable cartridge drives are gradually eroding the
floppy drive's market by offering exponentially larger
capacities and better reliability with media of roughly the same size.
refresh rate
The rate at which the screen is redrawn, usually measured in Hz (cycles per second).
An input device that uses light-sensing equipment to import documents into
programs as images to be edited and saved. The image produced from scanning a text
document can be converted back into editable text through OCR software.
SCSI
Small Computer System Interface: An interface for connecting devices and
components to a computer, usually through a single chain. SCSI devices can be
connected externally or internally, but a SCSI controller is required in either case.
The speed at which data can be transferred along a SCSI chain depends on the
quality of the controller; however, almost all SCSI controllers provide better
performance than parallel ports or serial ports.
SCSI ID
The number assigned to a SCSI component that the SCSI controller uses for identification.
serial port
A comparatively old interface for connecting devices to the computer that
allows the transfer of relatively little data in a given amount of time. The serial
port is mainly used with mice and external modems, but it is also sometimes used
with digital cameras to transfer picture files.
SIMM
Single In-line Memory Module: a circuit board upon which RAM resides.
SIMMs have a 32-bit data path and must be installed in pairs if used with a 64-bit memory bus (found on most new computers).
standoff
A small plastic or metal piece that holds the motherboard away from the case.
swap file
A file that Windows uses to temporarily store data. It is used to supplement
the computer's physical memory. The hard drive space that Windows allots for the
swap file is know as virtual memory.
USB
A relatively new technology for connecting external computer components to
each other and to the computer. USB devices are daisychained together,
much like SCSI devices, but the devices do not have
to be connected to separate power outlets because power is carried through the
USB cable. The main advantage to USB is that it simplifies cable hook-ups around
the computer. It also allows relatively fast data-transfer rates. Almost all new
computers built since the end of 1996 have at least one USB port.
Because USB technology is still in its infancy, it is
recommended that USB devices only be used with computers running Windows 98.
Although Windows 95 OEM Service Release 2.1 includes USB support, USB
devices have been known to function unstably and inconsistently with it.
