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

Significant Bits MeaningISWEX Diagnostic Position: Bits 5 through 15 assume the following meanings when theplug is connected to the diagnostic position in the disk storage module.5 Head settling. The read/write heads are settling following a seekoperation.6 Address mark time. The disk file is in address mark (AM) time.7 Pre-ID time. The disk file is in pre-ID time.8 Bit ring 0. The bit ring 0 line is active in the disk storage module.9 Write data to file. A logical 1 is being written on the disk.10 CC register position 17. Position 17 of the cyclic check register isactive.11 Bit ring inhibit. The bit ring inhibit line is active.12 Index time 4. The disk file is in index time 4.13 Data buffer busy. The file is transferring data between the data bufferand a disk.14 Index sensed. The index on the selected disk is being sensed.15 IPL select lower. The IPL select switch on the disk storage modulewas set to address the lower disk for an IPL operation.Read DSW0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA00001 XXX 0 10000000111 **** ** XXXX XX1 iii I i I I I I 1 I I I I i IIII 111110 8-F 4 0 7 0 0-3 XThis command stores the device status word (DSW) associated with the disk storage moduleinto the index register (R), or the accumulator if R=000.Execution of the read DSW command resets the bits in the DSW.Device Status Word (DSW): The bits in the 16-bit DSW are set by error conditions detectedduring the execution of an immediate command addressed to the I/O module. Themodule notifies the operating program of these error conditions by returning conditioncode 1 to the processor. If other commands are attempted before resetting the DSW bits,a condition code of 1 continues to be returned to the program.The significant bits in the disk storage module DSW and their meanings are:Significant Bits Meaning1 Command reject. The disk storage module cannot-execute the commandfor one of the following reasons:1. The command is invalid for the disk storage module.2. The present state of the disk storage module prevents executingthe command, although it is a valid command for the module. (Forexample, a read data command issued when the module is in thewrite data mode.)4 Intervention required. The disk file drive is not ready for use by thesystem. This condition may or may not be caused by a failure in thedisk storage module. Additional information can be obtained fromthe ISW and ISWEX.14 Data check. The disk storage module has detected a parity error involvingdata. The operation that caused this condition usually can beretried successfully if the error condition is intermittent.IBM 5022 Disk Storage Module 15-25