IBM System/7 Functional Characteristics - All about the IBM 1130 ...

Recalibrate Operation: A recalibrate operation returns the access mechanism to cylinder 0and selects a specified disk and head in the disk storage module. The recalibration is performedby a seek command that specifies moving the access mechanism in the reversedirection across 224 or more cylinders (bits 8 to 15 of the control information word equal1110 0000 or greater).Write Initialize (DPC)O 5 8 11 16 20 26 31Op codeRFunZerosMod0 0 0 0 1XXX 0 0 1 0 0 0 0 0 0 1 1 1 XXXXXX1 1 1 1 ii1 11 1 1 11 1 1 1 1 1 1 11 1 1 1 1••■■■••,en../..•■••••■•■■•••■■■■•■•.„,•••■•,■••••••,...11.,••■■••■,,■■••■ •■•••••■„,...., ••■••■••■,....0,.../..,./.11w,O 8-F 2 0 7 0 0-3 XThis command places the disk storage module in the write data mode of operation andsearches for the sector identifier specified by the control information word contained in theindex register (R), or the accumulator if R=000. The control information word has thefollowing format:O 2 1011 15DAMAF C T S1 1 11Sector identifiers are read on the track previously specified and compared to the identifierspecified by the control information word. When the specified sector is found, a dataserviceinterruption request is presented to the processor module. If the sector is not foundafter at least one complete revolution of the selected disk, the no-record-found bit (bit 5)is set in the interrupt status word and an interruption request is presented to the processor.Upon completion of an error-free write initialize command, the disk storage module canaccept only a write data or terminate command. Write data mode is reset by either anend-of-sector or an any-error interruption request.Write Data (DPC)0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MAoooo xx oal ooooo 0 0 0 ******XXXXXX1 1 1 1 it 1 1 till III 1 1 1 1 1 1 1 1 1 1'•■•■N,...■/,..sw.s,omwr''',....,.emrmr' '',•••Ne•••••" '`••••••■■'''■•••1■'"'■••••■e•■•••''''■•••■■...."'O 8-F 2 0 1 0 0-3 XThis command transfers one 16-bit data word from the index register (R), or accumulatorif R=000, to the disk file data buffer. The write data command is valid only after a writeinitialize command has placed the disk storage module in the write data mode of operation.Data-service interruption requests occur at 40-microsecond intervals. Four write datacommands must fill the disk file data buffer within this interval to avoid a data overruncondition. If the data buffer is not filled within 40 microseconds, the overrun error bit(bit 2) is set in the interrupt status word and a device-end interruption is presented. Oncethe data buffer is filled, the disk storage module is busy to any more write data commandsuntil the next data-service interruption request occurs.After 128 data words and the appropriate check character for the entire data field aresuccessfully written, the end-of-sector bit (bit 7) is set in the interrupt status word andan interruption request is presented. (See "Read Data" for programming note.)