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

I/O Transfer BlockThe address of the IOTB must be stored at location 0008 prior to an initiate I/Ocommand.After the initiate I/O instruction is accepted, the 5024 controller starts tocycle steal the IOTB. The controller will ignore the unused control parameters(printer status address and word count). One full card (80 columns) is read whenever acard read operation is completed. In order to read another card, another initiate I/Omust be issued.0 3 8 15CommandZerosNot usedCommand WordI I 1 1 1 10000 Reserved0001 Output EBCDIC translate table0010 Read 2502 EBCDIC0011 Read 2502 BINARY0100 Disable 2502 attention interrupt0101 Output diagnostic/initialize controller0110 Input diagnostic0111 Enable 2502 attention interruptThe command word defines the operation to be performed. Bits 0-3 are the command, bits4-15 are zeros when used with the 2502. Five commands within the command word are usedby the user program.• Ouput EBCDIC Translate Table 0001. This command transfers the EBCDICtranslate table from main storage to the card reader attachment, and must beexecuted without error before a Read 2502 EBCDIC command can be executed.For a description of the translate table see 2502 Card Read Translate Table in thischapter.• Read and Translate Card Code Mode 0010. The 2502 reads the 256 holepatterns of 80-column card code. Translation is from punched card code to EBCDIC.Each 16 bit word transferred to storage contains information from two card columns.If this command is issued before command 0001, bits 1 and 2 will be set on instatus word 1 and the command will not be executed.• Read Binary Mode 0011. The 2502 reads column binary, all bits beingvalid. No translation takes place. Each card column represents a 16 bit word withHole 12 being the high-order bit (bit 0). The low-order four bits (bits 12-15) areforced to a zero state.• Disable Attention Interrupt 0100. This command will disable the2502 Attention Interrupt. Any initiate I/O command (other than the disablecommand) issued to the reader, re-enables the attention interrupt.• Input Diagnostic 0110. This command is used by the customer engineer for diagnosticpurposes. If this command is used in a user program, unpredictable results will occur.17-10.2 GA34-0003- — - !Ilimppgmlwimounimp l 111■muM p 1,141111 1111111,101,7