O OXIDE— A ferrous material that can be magnetized; also, the recording side of the magnetic tape (dull side). P PARALLEL   PROCESSING—   Handling   all   the elements of a word or message simultaneously. PASCAL—   High-level  structured  programming language that has gained wide acceptance as a tool for   both   applications   programming   and   system development. PENTIUM CHIP— A processor chip that can execute many instructions at the rate of two instructions per clock cycle. PERIPHERAL EQUIPMENT—  Equipment used for data entry, storage, or retrieval, but which is not part of the central processing unit. Peripherals include crt displays, terminals, printers, and mass storage (tape, disk, and drum) devices. PHOTOELECTRIC   CELL—   A   mechanism   that when  activated  by  a  light  source  emits  an  electrical impulse. Q QUERY—  To make a request for information from a database system. R RECONCILING—   Refers   to   the   correcting   of processing discrepancies. R E L A T I O N A L    D A T A B A S E —  A   database organization  scheme  that  treats  files  as  tables  of data   in   which   the   rows   represent   fixed-length records and columns represent fields. RIGID—  Refers  to  the  hard  metal  platters  (usually constructed of aluminum or glass) that comprise a hard  disk. S SCHEMA—  Structure  for  organizing  knowledge relative to context or expectations. SCRATCHING MAGNETIC MEDIA— Making the magnetic media available to the computer operator for reuse. SCSI   ADAPTER—   A   general   purpose   parallel interface   designed   for   connecting   one   or   more computers and one or more peripherals. A total of 8 devices may be connected to one bus. SEMICONDUCTOR—   A  crystalline  substance  that conducts   electricity   when   it   is   “doped”   with chemical impurities. SERIAL— Pertaining to the sequential occurrence of two or more related activities in a single device. SILICON CHIP—  Tiny portion of a silicon wafer with thousands  of  electronic  components  and  circuit patterns etched on its surface. SIMPLEX—  A  mode  of  data  transmission  in  which data  can  travel  in  only  one  direction  on  the  line. When a terminal is connected to such a circuit, it can be used to either receive or send data to the cpu but not do both. SINGLE-FILE  DIRECTORIES—  An option of the operating system that allows for only one file to be contained  in  a  directory. SOFT-SECTORED—  Method of marking sectors or sections on a disk by using information written on the  disk. SPECIAL FUNCTION KEY— Key on a keyboard to control  a  mechanical  function,  initiate  a  specific computer  operation,  or  transmit  a  signal  that  would otherwise require multiple key strokes. STAND-ALONE—  Self-contained  computer  system that can work independently, not connected to or under the control of another computer system. STRIPPING— The removing of the first 100 feet of the magnetic  tape.  This  is  the  portion  that  becomes contaminated and causes the most errors. SUBSCHEMA—   Logical   organization   of   data required for a particular program. SURGE   PROTECTOR—   Device   that   protects electrical equipment from being damaged by short surges of high voltage by filtering them out. T TIMING—  The regulation of the flow of signals that control the operation of the computer. TREE  STRUCTURED  DIRECTORY—  A  disk containing   a   root   directory   and   several subdirectories. AI-3