IBM 5280 Distributed Data System - Index of

Diskette lOBFollowing is a general description of the diskette lOB. Follovving this generaldescription is a complete description of each field of the lOB. Addresses shown arehexadecimal displacements from the beginning of the lOB. No validity checking ismade on any of the values in the bytes of the following lOB. If any of these bytesare modified by the application program, unpredictable results may occur.00 lOB System lOB Chaining Information Page Data and Error Code Next Instruction AddressStatu:;F!2gS1 1 1108 Command Command Operands Logical Buffer Address Translate ExternalOp Code Table Num- Statusber1 1 1,210 Address of External Status Main Micro- Data Set Address of Data Set System Use PartitionSubroutine or Subroutine processor Flags Name Only Address,Table Flags High1,2,3 1,2,3 1,2 118 Physical I/O Buffer 1 PBI Track PBI Sector Logical Record Length Block Length(PB1) Address and Length1,2 1 1 1,2,3 1,2,320 Physical I/O Buffer 2 PB2 Track PB2 Sector Defective Sector Count Microprocessor Save Area(PB2) Address and Length1,2 1 1 1,3 1,328 Displacement to Next Microprocessor Save AreaRecord Space1,3 1,330 Pointer to HDR1 Label Sector Number of N'umber of Number of Track and Sector Number ofAddress Length Additional Index Sectors per Sectors per Beginning of Extent (BOE)Cylinders Block Track1,3 1,3 1,3 1,3 1,3 1,338 Relative Record Number of Relative Record Number of Track and Sector Number ofEnd of Data (EOD) End of Extent (EOE) End of Data (EOO)1,3 1,3 1,340 System Use Table Num- Number of Records Between Key Position Key Length System UseOnly ber of Key Keys Minus 1 OnlyIndex File4 1,2.4 1,2,3,4 1,2,4 1,2,4 448 Microprocessor Save Area Data Set Type Adapter Micropro-Error Status cessorSave Area1,3 1,2 1 150 Number of Bytes to Microprocessor Save Area Seek Count Microprocessor Save AreaRead or Write(PBl)1 1,3 1 1,378