Product guide

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Appendix C Glossary
onboard SRAM can be used as both a cache or buffer.
Because the RAM does not have to send its information to an
external SRAM cache, overall system performance is
considerably improved .
Cache RAM: Cache is a small block of high-speed memory
(usually SRAM) located between the CPU and main memory
that is used to store frequently requested data and instructions.
When the processor needs data, it will check in high-speed
cache first to see if the data is there. If not, then the processor
will retrieve the data from slower main memory.
CD-ROM: Compact Disc-Read Only Memory. An information
(data) storage device that uses compact disc technology. CDs
can store over 650MB, until recently they could not be written
to, hence the appellation Read Only.
CISC: Complex Instruction Set Chip. A processor where each
instruction can perform several low-level operations such as
memory access, arithmetic operations or address calculations.
Also see, RISC.
Client / Server: A common form of distributed system in which
software is split between server tasks and user / client tasks. A
client sends requests to a server asking for information or
action, and the server responds. There may be either one
centralized server or several distributed ones.
Clock: A circuit that sends a consistent, periodic signal used to
synchronize the computer and to step information through the
system.
Closed: A complete circuit. Usually accomplished by placing a
jumper over two pins on the system board or a peripheral card.
Also see “Open” and “Jumper.”
Cluster Server: A group of independent servers managed as a
single system thus allowing higher hardware availability, easier
manageability and greater network scalability.
CMOS: Complementary Metal Oxide Semiconductor. A logic
circuit family that uses very little power. It stores system setup
information including system hardware settings. Sometimes used
to store information by applying constant, uninterrupted power
through the use of an external battery.
Collapsed Backbone: Network architecture under which the
backplane of a device such as a hub performs the function of a
network backbone; the backplane routes traffic between desktop
nodes and between other hubs serving multiple LANs.
Compact Disc: A 4.72 inch disc that can store still and / or
moving images in monochrome and / or color; stereo or two
separate sound tracks integrated with and / or separate from the
images; and digital programs and information files.
Controller: This part of a computer, typically a separate circuit
board, allows the computer to use certain kinds of peripheral
devices. Disk controllers connect hard disks and floppy disks.
The most common disk controllers in use are IDE and SCSI
controllers. Most home personal computers use IDE controllers.
High-end PCs, workstations and network file servers mostly have
SCSI controllers.
Coprocessor: A microprocessor device that performs specialized
computations which assists the main processor by performing
certain special functions, usually much faster than the main
processor could perform them in software. The coprocessor often
decodes instructions in parallel with the main processor and
executes only those instructions intended for it.
CPU: Central Processing Unit. The integrated circuit chip that
performs the actual computing functions of the computer. Other
chips perform support functions like storing data and controlling
peripherals. Also see microprocessor.