Active Matrix Display
An LCD technology used in flat panel computer displays. Using a transistor for each pixel, it produces a high quality display.

Audio Card
Also called a sound card, a sound board, and audio adapter, it is a personal computer expansion board that records and plays back sound, providing outputs directly to speakers or an external amplifier.

Central Processing Unit (CPU, Processor)
A chip inside the computer that essentially functions as the brain of the computer. It is the single greatest determinant of a computer's power and speed.

Clock Speed
The number of instructions a processor can execute per second. Clock speed is measured in millions of instructions per second (megahertz, or MHz). It is a good indicator of performance only when comparing the same type of chip.

Docking Station
A unit designed to convert a notebook computer into a full desktop computer system. Docking stations typically contain connections for peripherals, monitors, printers, and a keyboard, and some even contain additional hard drives or memory.

DVD
Stands for digital versatile disk. It is a relatively new storage standard for data and video images, capable of holding up to 17 GB on a single disk.

DVD Drive
Reads the data on a DVD disc. DVD drives are also backward-compatible with CD-ROMs, which means they can play old CD-ROMs, CD-I disks, and video CDs, as well as new DVD-ROMs. Newer DVD players can also read CD-R disks.

Gigabyte (GB)
One thousand megabytes of data. A gigabyte is equivalent to about one billion words. Gigabytes are often used to measure the size of a hard drive.

High Capacity Floppy Drive
Floppy disk drives that record data onto disks that can hold 100 MB or more of data. Examples are the Zip and Jaz drives manufactured by Iomega Corporation.

Megabyte (MB)
One million bytes of data. A megabyte is equivalent to about one million words. Megabytes are often used to measure the size of a hard drive or the RAM of a computer.

Operating System (OS)
A basic program controlling how you can use and operate the computer. All Apple Powerbooks use the MacOS. PC notebooks typically use Windows 98 since it is better equipped to manage notebook power consumption, but some notebooks are sold with Windows NT.

Parallel Port
A specific type of socket on a computer used to connect a printer or other peripheral device. It may also be used to attach a portable hard disk, tape backup, or CD-ROM.

PC Card (PCMCIA)
A common notebook interface for adding modems or network interfaces to a notebook computer. A PC Card is the size of a thick credit card and slides into a slot on the side of many notebooks. PC Cards can also be used to transfer data between other digital devices (such as a digital camera) and a computer.

Pointing Stick
A pointing device that uses an eraser-sized knob to provide cursor movement. This pointer works like a joystick, moving the cursor in the direction it is pushed.

Processor
Also called a CPU (Central Processing Unit), it's the computing part of the computer. A personal computer CPU is a single microprocessor chip. A minicomputer CPU is contained on one or more printed circuit boards. A mainframe CPU is made up of several boards.

RAM (Random Access Memory)
A temporary form of memory used to hold applications that are being accessed by the processor. Adding memory is a very effective way to increase the working speed of a computer, since it decreases the need for the processor to read data off the (comparatively) much slower hard drive. RAM for modern computers typically ranges from 16 MB to 128 MB.

Resolution
The number of dots of light that appear on a monitor. Higher resolution means more dots appear on the screen, allowing a larger image to be displayed. Most notebooks offer a resolution of 640x480 dots, but a few models can show 800x600 dot images.

Serial Port
A type of socket on a computer used to connect a modem, mouse, scanner, or other serial interface device to the computer.

STN
Another term for dual-scan screen. Dual scan screens are not as bright as active matrix screens and must be viewed nearly head-on to see a clear image. STN screens, however, use less power than active matrix models and are several hundred dollars less expensive.

Swappable Drive Bay
An area of reserved space in a personal computer where hard or floppy disk drives (or tape drives) can be easily swapped in and out.

Tape Backup
The use of magnetic tape for storing duplicate copies of hard disk files.

TFT
Another term for active matrix screen. TFT screens are much brighter and more responsive than dual scan screens. They do, however, consume more battery power.

Touchpad
A type of interface used instead of a mouse on many notebooks. A touchpad is a small plastic square that allows you to move the cursor by dragging your finger across the pad.

USB Port (Universal Serial Bus)
An external bus standard that supports data transfer rates of 12 Mbps (12 million bits per second). A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, and keyboards.