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

Programming Note: The terminate command, instead of the four read data or write datacommands, must be issued following a data-service interruption request.Condition code errors to read or write operations can be interrogated to determine ifan overrun interrupt is pending or if no interrupt should be expected. If condition code1 is received, the DSW can be read to determine if the error was command reject or datacheck. If command reject, no other interruption will be presented. If data check, the programwill receive an overrun interrupt. If condition code 2 is received, it indicates thatthere is another interruption pending. This interruption may indicate overrun or anyother error condition, such as, drive became not ready or equipment check.Looping on a halt I/O command before the file becomes ready will keep the file frombecoming ready. If a halt I/O or system reset occurs, a load next sector ID or seek operationmust be performed to select a head before doing a read, write, read verify or formattrack operation. If a halt I/O is performed when the file is not ready due to an unsafecondition, the file will become ready. If the file is prepared to interrupt, it will present aninterrupt with the attention bit (0) on.Read Cycle Steal (Cycle Steal Feature)0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 XX I 1 0 0 0 0 0 0 0 0 0 1 ******XXXXXXI I I I 1 I 1 1 1 1 1 1 1 1 1 1 I 1 1 1 I 1 1 1 1.."..."'"\e""•••••"0 8-F C 0 1 0 0-3 XThis command causes the device to cycle steal data from the disk into main storage.The index register (R), or the accumulator if R =000, contains the starting address ofthe DCB. The DCB contains the information needed to perform the operation. Thedisk module is busy to all commands, except status reads, from the time this commandis issued until the channel end interruption.Read Residual Address (Cycle Steal Feature)0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 XXX 0 1 0 0 0 0 0 0 1 1 1 1 *** ***XXXXXXI I I I II II I I I I III I 1 1 1 1 I 1 1 1 10 8-F 4 0 F 0 0-3 XThis command reads the contents of the data address register which is updated by the5022 attachment sub channel. The purpose of this command is to indicate to theprogram, for recovery purposes, the exact point during data transfer at which a subchannelerror or exception condition occurred. The data address register in the subchannel is notreset by this command or by a halt I/O command. It is reset by a system reset. Theread residual address command does not cause an interruption.If a check character error for the sector ID is detected, the data address register containsthe address associated with the first word of that sector. The any-error bit (bit 3), norecord-foundbit (bit 5), channel-end bit (bit 11), device-end bit (bit 13), and the readISWEX bit (bit 15) are set in the ISW. The file-data-check bit (bit 4) is set in the ISWEX.During a multisector operation, if the ID word is not the next sequential ID, the dataaddress register contains the address associated with the first word of the new sector.The any-error bit (bit 3), channel-end bit (bit 11), device-end bit (bit 13), and theread-ISWEX bit (bit 15) are set in the ISW. The missing-address-mark bit (bit 1) is set inthe ISWEX.IBM 5022 Disk Storage Module 15-15