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

Device Status Word (DSW): The 16-bit device status word associated with the 1130 hostattachment has various bits set on to indicate program operating status and detected errors.The significant bits in the DSW presented to the 1130 processor and their meanings are:Significant Bits Meaning0 Attention. A System/7 set interrupt command is directed to the 1130.This is not an error.1 Operation end. The word count equals zero, or a power/thermalwarning or error was detected during a data transfer operation.2 Invalid storage address. The 1130 has attempted to address a storagelocation outside the installed capacity of the System/7. This is an error.3 Data check. A System/7 parity error was detected by the 1130 hostattachment when fetching words from System/7 storage. This is anerror.4 Count = 0. The word count register in the 1130 host attachment isequal to 0. This is not an error.5 Power or thermal warning. A power failure or thermal warningcondition has occurred. This bit is not reset by the sense-device IOCC.(Refer to "Power Failure and Thermal Warning" in Chapter 1 and"Class Interruptions" in Chapter 3.)6 Storage control check. The 1130 host attachment detected thatSystem/7 storage has not responded to the attachment's request for astorage cycle, sometimes referred to as an "overrun" condition. Thisis an error.14 Ready. The System/7 is on line and power is good. This bit is not resetby the sense-device IOCC. This is not an error.15 Busy. The 1130 host attachment is performing a data transferoperation between the attachment and System/7 storage. This bitis turned off as soon as the operation-end bit (bit 1) is set on. Any1130 command (except sense-device) to the 1130 host attachmentis ignored if the busy bit is on. This is not an error.Electronic Initial Program Load (EIPL)0 16 21 24 31AddressDevice Fun Modifier0 1 1 0 0 1 0 1 0 0 0 010 0 1 0IIIIIIIIIIIII1 1 I I 1 11 11 1 1 1 1 1 1s■Nes•••■■■,■0' .......„,■•.....•■••••••-v■,•■•■■•■••••••■■■••• •••••■••■■••■X X X X 6 5 0 2An XIO instruction with this special initiate-write IOCC is used to IPL the System/7 fromthe 1130. Modifier bit 30 in this IOCC serves a dual purpose for the EIPL function. Thisbit also establishes a temporary "prevent" status for attention and power/thermal interruptions.Thus, the 1130 will not recognize an attention or power/thermal warninginterruption during an EIPL to the System/7. The basic interruption status must bereestablished by a control command with modifier field bit 30 = 0 or by an initiate reador initiate write command.The host attachment switch on the System/7 console must be in the enable and IPLposition for this command to perform the IPL. When the 1130 host attachment recognizesthe EIPL command, the System/7 does a system reset and enters the wait state. The hostattachment sets the System/7 address to 0 and proceeds with the EIPL as if it were anormal initiate-write from the 1130.