Glossary 109
Cache memory
Cache is very fast, zero-wait-state memory. Cache reduces the average time
required for the microprocessor to get the data it needs from the main memory by
storing recently accessed data in the cache.
CardBus
CardBus technology enables the computer to use 32-bit PC Cards. Hardware in
the computer and the Windows 98 operating system provide support for the 32-
bit cards. The voltage of 32-bit cards (3.3 volts) is lower than that of 16-bit cards
(5 volts). The 32-bit cards can transmit more data at a time than the 16-bit cards,
thus increasing their speed.
CMOS memory
CMOS (complementary metal oxide semiconductor) memory is powered by the
CMOS battery. The System Setup settings and other parameters are maintained in
CMOS memory. Even when you turn your computer off, the information in
CMOS memory is saved.
COM port
COM stands for communication. COM ports are the serial ports in your computer.
Compact Disc
A compact disc (CD).
Conventional memory
The first 640 KB of system memory. Operating systems and application programs
can directly access this memory without using memory-management software.
Disk
The device used by the computer to store and retrieve information. Disk can refer
to a floppy disk, hard disk, or RAM disk.
Disk cache
A software device that accumulates copies of recently used disk sectors in RAM.
The application program can then read these copies without accessing the disk.
This, in turn, speeds up the performance of the application.
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.
