lOB 0 IOBSTAT 4
8
C
14 IOBCLASS 18
1C 20 24 2S IOBFLAG 1 1 11 1 IOBOPT 115 I IOBTYPE IOBCYlP IOBMTCK IOBVSER 129 I 12 1 IOEUAtI IOBCCW IOBEBBOR IOBCSW 116 1 11A I t 1E 1 f 126 I Reserved IOEMB!C IOECYLA 11F IOBMODE I IOEATAPE for IBM use Status of IOE IOBDISP n!! for IOBSTAT IOBST EQU 1'80'-- I/O unit is to be started IOBSTACK EQU X'40' I/O error has been stacked IOBlAST EQU X'20' last lOB IOBNOPER EQU X'10' Device is not operational IOBCPVOl EQU X'OS' Unit is a CPVOL IOBOPEN EQU X'04' The lOB is open IOBSCRAT EQU X'02' The DASD device is a scratch volume IOBTPSWP EQU X'01' Switch to alternate tape in progress IOBOPT DS 11 lOB flags for IOBOPT IOBDEW EQU I'SO'---Wait for device end interrupt IOBERST EQU X'40' Stop on I/O error and wait for next interrupt IOBEEXIT EQU 1'20' Repeat CCW on error IOBSIO EQU X'10' Do not use Diagnose I/O Figure 5-5. lOB (Input/Output Block) Format (Part-1 of 2) 10S IBM V8/370 Service Routines Program Logic

Hex --"2 4
8 C 14
15
16
16
18 11 1C 1E 1F 20 26
28
29 2
4
8
12 20 21
22
22
24
26
28 30 31
32
38 40 41 !:ield_NaJ!! IOBUADD Ds 1H IOBCCi Ds 1F IOBERROR Ds A IOBCsi Ds 2F IOBCLAss Ds X'O' IOBTYPE Ds X'O' lOBS KIP EQU * IOBMREC Ds H'O' IOBCYLP Ds H'O' IOBCYLA Ds H'O' IOBMTCK Ds lOBMODE DS IOBDIsP Ds IOBVsER Ds IOBATAPE Ds IOBFLAG Ds
Ds H'O' X X CL6' , X'OOOO' X'O' 3X'0' IOBSlZE EQU *-IOB Unit address of device Pointer to cei
Address of 10 error routine Csi of 10 error stacked
Device class
Device type lOB type skip count Maximum nuaber of records that will fit a track Maximum primary cylinder address of DAsD device. Maximum alternate cylinder address of DAsD device. Maximum nuaber of tracks (numbering C-N) lOB tape mode command code rOB tape disposition command code Volume serial number of DAsD unit
Address of an alternate tape unit rOB flag
Reserved for rBM use
Address of an alternate tape unit
Figure 5-5. rOB (Input/Output Block) Format (Part 2 of 2)
Chapter 5. The D!SD Dump Bestcre Program 109