IBM 847651U Handbook - Page 331

bus. One or more conductors used for transmitting signals, data, or power. See also address bus and data bus. bus master. A device or subsystem that controls data transfers between itself and a subordinate. C cable. The physical medium for transmitting signals; it includes copper conductors and optical fibers. cache. A buffer storage that contains frequently accessed instructions and data; it is used to reduce access time. loading, and other machine-related functions. client. A functional unit that receives shared services from a server. (T) clock. A device that generates periodic, accurately spaced signals used for purposes such as timing, regulation of the operations of a processor, or generation of interrupts. (T) code. A collection of instructions that is in a form that can be read and processed by a computer. collision. An unwanted condition that results from concurrent transmissions on a channel. (T) CD. Compact disc. A disc, usually 4.75 inches in diameter, from which data is read optically by means of a laser. CD-ROM. Compact disc read only memory. High-capacity read-only memory in the form of an optically read compact disc. See also CD. compatibility. The capability of a hardware or software component to conform to the interface requirements of a given computer without adversely affecting its functions. CMOS. complementary metal oxide semiconductor central processing unit (CPU). (1) Synonym for processing unit. (T) (2) The part of a computer that includes the circuits that control the interpretation and execution of instructions. See central processor, processing unit, and processor. central processor. A processor that contains the sequencing and processing facilities for instruction execution, interruption action, timing functions, initial program complementary metal oxide semiconductor (CMOS). A technology that combines the electrical properties of n-type semiconductors and p-type semiconductors. See also NMOS, n-type semiconductor, PMOS, p-type semiconductor. The positive and negative voltage requirements of paired p-type and n-type semiconductors complement each other. A low-power input pulse to a gate of a CMOS device turns one Glossary 297