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

None of the data read is transferred to the processor module; the data field is merelyread and the generated check character is compared against the check character read fromthe disk for that sector. If the check characters are identical, a normal device-end interruptionrequest is presented to the processor module with the end-of-sector ISW bit (bit 7)also set. If the check characters are not identical, the file-data-check bit (bit 4) is set inthe interrupt status word and an interruption request is presented.Write Diagnostic Control0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 XXX 001 00000 1011 ** * ***XXXXXX1111 II II 1111 III 11111 111110 8-F 2 0 B 0 0-3 XThis command disconnects the disk file from its controlling circuitry in the disk storagemodule so that certain signals and timing pulses can be simulated for testing by the customerengineer.The control information word used by this command is contained in the index register(R), or the accumulator if R=000, and has the following format:0 4 5 6 1011 13 15X 000 XXXO 00 XX 0 X 0 X1111111111111BitWrite oscillator 0Address mark indicate 4Separated clock 5Separated data 6Index 10Track crossing 11Set file ready 13Reset diagnostic mode 15The write diagnostic control command is used in conjunction with the read ISWEX command,described later.Before signals and timing pulses can be simulated with this command, the disk file mustbe placed in diagnostic mode by executing a write-diagnostic-control command with a controlinformation word containing 0. A bit in the ISWEX turns on and remains on to indicatethat the disk storage module is in diagnostic mode. The file can enter diagnosticmode only if it is not in any other mode at that time. While the file is in diagnostic mode,all other read and write commands can be issued to the disk storage module just as if themodule were not in diagnostic mode.15-18 GA34-0003