IBM 5280 Distributed Data System - Index of

Hex Length inDisplace- Bytes {inment Hex} Description0020 20 System use only.0040 20 Diskette lOB Pointers (eight 4-byte blocks). ~ach 4-byteblock has the following meaning:Byte 0Flag ByteBitrs)Meaning0 The diskette microprocessor has locked thelOB pointer; the main microprocessor cannotuse the lOB pointer while this bit is on.1-2 System use only.3 A label update data set is open. The mainmicroprocessor cannot put another lOB onthis chain.4-7 When not 0000, the main microprocessoris using the lOB chain.Byte 1The high-order address of the first lOB onthe chain.Byte 2Bitrs)Meaning0 The low-order bit of the lOB address.1 The diskette drive is installed for this lOBpointer.2-3 System use only.4-7 The page number in storage where the lOBis located.Byte 3Diskette microprocessor save area.0060 20 System use only.0080 4 Printer lOB pointer (same meaning as a diskette lOBpointer, displacement 0040).0084 1C System use only.Main Storage Data Areas 29