Keyboards,  3-11 Keyset central multiplexer (KCMX), 13-15 L Language instructions, 8-5 Layouts assembly/chassis, 2-4 backplane/motherboard, 2-6 block diagrams, 2-2 card cage/rack, 2-4 Functional,  2-3 modular, 2-4 physical,  2-4,2-6 Levels of instruction, 8-3 Limitations, operational, 1-13 L i n e conditioners, 4-29 drivers/receivers, 4-20, 4-21, 7-21 Line printers, 12-7 chain and band printers, 12-8 drum printers, 12-7 Linear ICs, 4-18 family types, 4-18 fictional   uses,   4-20 gates,  4-19 groups, 4-19 Lines data,  7-32 input  data,  7-33 output  data,  7-33 Load/write control memory, 7-14 Logic circuits, digital, 4-4, 4-9 gates, digital, 4-9 Logical operations, 5-23 M Main timing, 5-4 Mainframe computers, 1-3, 8-8, 8-23 bootstrap, 8-25 configuration, 8-23 controls,   8-23 data  entry/display,  8-23 diagnostics,   8-25 initiate operational programs, 8-25 instruction format, 8-8 interrupt/lockout,  5-12,    5-14 power, apply, 8-23 revise/patch software, 8-26 Magnetic disk data encoding methods, 10-25 drive  unit,  10-19 file unit controls and indicators, 10-15 fixed hard drive system, 10-23 floppy disks, 10-7 memory sets, 10-13 Magnetic disk packs, 10-14 data surfaces, 10-14 servo surface, 10-14 Magnetic  disk  storage,  10-1 data  organization,  10-3 disks and disk drives, 10-2 Magnetic  tape,  9-1 construction,   9-2 devices, 9-11 handling procedures, 9-2 maintenance,   9-3 recording methods, 9-7 storage,  9-6 transport,  9-15 Magnetic tape controller, 9-12 control  unit,  9-13 control  panel,  9-14 microprogrammed controller, 9-13 Magnetic tape unit operations, 9-12 offline  operations,  9-13 programmed controller, 9-13 read/write,  9-12 rewind, 9-13 search,  9-12 space  file,  9-12 Maintenance consoles, 3-10 Man/machine  interfaces,  8-1,8-15 functions,   8-16 mainframe computer, 8-23 microcomputer, 8-16 minicomputer, 8-20 operating  modes,  8-15 operations,  8-15 Mapped I/O memory, 7-14 Master clock, 5-4 Mated film, 6-17 Math pat, 5-23 Matrices,  6-16 INDEX-8