shift,  4-18 status indicating, 5-7 storage,  4-17 Regulators, 4-26 inhibit  current,  6-13 integrated circuits, 4-19 switching, 4-20 voltage,  4-20 REI,  5-25 Relative operand addressing, 8-14 Remote consoles,  3-13 operator  control  units,  3-13 Requestor extension interface (REI), 5-25 Requests independent  control,  7-18 input  data,  7-33 output  data,  7-33 Requirements functional operations, 1-14 operational, 1-14 power,  2-21 Ribbon cables, 2-24 Ring, token, 7-24 ROM, 5-17, 6-26 ROM based diagnostics, 8-18 RS-232, 7-24 pin description, 7-30 RS-422, 7-24 RS-449,  7-23 RTC,  5-5 Run  mode,  8-15 S Safety/security features of frames/cabinets, 2-12 Sampling,  13-3 Search for sync/set suppress/set monitor, 7-14 Sectors,  disk,  10-3 Security, ADP, 1-14 Select  signal,  7-32 Selectors,  4-14 Semiconductor memory, 6-20 DRAM, 6-24 SRAM, 6-22 Sense amplifiers, 4-21, 6-13, 6-20 Sequence enables  and  control,  5-5 mode,  8-15 Sequence  of  events external  function,  7-34 external  interrupt,  7-34 input  data,  7-33 output  data,  7-33 single  cable,  7-32 two  cable,  7-33 Sequencing  circuits,  7-13 Sequential digital logic circuits, 4-10 Serial,  7-14 data  operations,  7-28 format,  7-9 Set/clear  flag,  7-14 Shift  registers,  4-18 Ship, switchboard, and computer switching control panel (CSCP) wiring, 13-34 Signals acknowledge,   7-32 audible  alarms,  3-2 busy,  7-32 command,  4-13 DCE/DTE, 7-29 enable,  4-13 select,  7-32 Single-cables,   7-32 sequence  of  events,  7-32 Single-channel  operating  mode,  7-11 Single-phase  clock  systems,  4-23 Size  instructions,  8-12 Small computer system interface, 7-23 SNAP systems, 1-9 Software,  1-10,  8-4 Software   revisions mainframe computer, 8-26 microcomputer,  8-20 minicomputer,   8-23 SPS,  4-30 SRAM,  6-22 ST-506/412,   7-27 Stack memory, 6-11, 6-16 queue,  interrupt,  5-13 Standards,  interfacing,  7-18 Standby power supply (SPS), 4-30 State,  executive,  5-10 State,  task INDEX-12