Glossary 101
A cache is a buffer for transferring disk sectors in and out of
RAM. Data stored in a disk cache is a copy of data already
stored on the physical disk.
DMA (direct memory access)
A method of transferring data from a device to memory
without having the data pass through the microprocessor.
Using DMA can speed up system performance.
DS-STN (Dual-scan super twist nematic) LCD
A DS-STN LCD uses a scanning matrix to control image
pixels. In a dual-scan STN screen, the matrix scans the image
twice each time the screen is refreshed. This provides a
better image than provided by single scan LCDs. An STN
LCD is also sometimes called a passive matrix LCD.
Floppy disk
A removable disk, also called floppy or diskette.
Hard drive
Also called fixed disk. A hard drive is connected to the
computer and can be installed or removed. Data written to
a hard drive remains until it is overwritten or corrupted.
The 2.5-inch hard drive in your computer was designed for
use in a portable computer. Because hard drives in portable
computers are smaller than those in desktop computers,
their maximum storage capacity may be less than that of
desktop hard drives. However, because of their smaller size,
the drives handle shock and vibration better than larger
drives, which is important for a portable computer.
I/O
Input/output. Refers to peripheral devices, such as printers,
that are addressed through an I/O address.
I/O address
I/O stands for input/output. Peripheral devices, such as
printers, are addressed through the I/O port address.
IRQ (interrupt request line)
The IRQ is a hardware line that a device uses to signal the
microprocessor when the device needs the microprocessor’s
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