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

Write Cycle Steal (Cycle Steal Feature)5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 XXXI 11000000001 ******XXXXXX1111 II II 1111 III 1 1 1 1 I 111110 8-F E 0 1 0 0-3 XThis command causes the device to cycle steal data from storage and write it on thedisk. The index register (R), or the accumulator if R=000, contains the starting addressof the DCB. The DCB contains the information needed to perform the operation. Thedisk module is busy to all commands, except status reads, from the time the commandis issued until the channel-end interruption.Read Verify Cycle Steal (Cycle Steal Feature)0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 XXXI 10000000010 ******XXXXXX1111 11 11 1111 III 11111 111110 8-F C 0 2 0 0-3 XThis command is used to validate data written on the disk. No data is transferred tostorage during its execution. The command would normally use the same DCB as aprevious write cycle steal command. The index register (R), or the accumulator ifR=000, contains the starting address of the DCB. The DCB contains the informationneeded to perform the operation. The disk module is busy to all commands, exceptstatus reads, from the time the command is issued until the channel-end interruption.Terminate (DPC)0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 * * * 001 0000010 00 *** ***XXXXXXlit 1 II II till III 1 I I 1 1 111110 8 2 0 8 0 0-3 XThis command suppresses data-service interruption requests. The terminate command isvalid only when the disk storage module is in the write data or read data mode of operation.When the disk storage module is in write data mode, 0's are inserted into the remainderof the data field on the selected sector and the appropriate check character for the entiredata field is written at the end of the data field.When the disk storage module is in read data mode, the remaining data field is readfrom the selected sector and the check character is verified, but no additional data transfersto the processor module take place.The end-of-sector bit (bit 7) is set in the interrupt status word and an interruption requestis presented after the check character is either read or written.Note: The terminate command may specify an index register (R), or the accumulatorif R=000. In write data mode, the contents of the register specified by R are ignoredby the disk storage module during execution of the terminate command. In read datamode, the contents of the register specified by R are not changed. (See "Read Data" forprogramming note.)IBM 5022 Disk Storage Module 15-13