Page of SY20-0884-3 As Updated Aug. 1, 1979 by TNL SN25-0497 IOBLOR IOBLOK cont.ains information required to perform I/O operations. The I/O request
initiator for the I/O operation is either a CP-initiated or virtual machine-initiated eVent. There are five pointers to the IOBLOK: RCHFIOB field of the RCHBLOK, ReHFIOB
field of the RCUBLOK, RDEVAIOB field of the RDEVBLOK, VDEVFIOB field of the VDEVBLOK, RDEVF10B field of the RDEVBLOK. 0 8 10 18 20 28 30 38
Hexadecimal
Displacement
------------ 0 2
3 r- I 10BRADD 11* 1 11*2 10BLINK I IOBFPNT IOBBPNT 10BCYL 10BVADD IOBMISC IOBUSER IOBIRA IOBCAW 10BRCAW IOBCSW IOBIOER 1*3 1*4 I 1*5 I RSV2 Field
Name 10BRADD DS 1H IOBFLAG DS 1X Bii§ Q.§iined in lOB FLAG IOBCP EQU --X'80'-- IOBRSTRT EQU X'40' IOBSPLT EQU X'20' 10BPAG EQU X' 10' TI"IDD"!:1Tr"n EQU VIAO. ..,L.v.uL\.uJ...l,"", U ,A-VU- IOBERP EQU X'04' lOB RES EQU X'02' 10BHVC EQU X
C 01; IOBSTAT DS 1X B:li§ Q.§iined i!! IOBFATAL EQU X'80' IOBFLT EQU X'40' IOBPATHF EQU X'20' IOBMINI EQU X'08' IOBALTSK EQU X'04' IOBCC3 EQU X'03' IOBCC 2 EQU X'02' IOBCC1 EQU X'01' IOBCCO EQU X'OO' 1OBMISC2 10BCUBSY Field Description, Contents, Meaning
Real device address for SIO 1*1 IOBLOK flags
CP-generated I/O operation
Restarted operation - IOBRCAW DASD - CP split seek operation IOBLOK created for paging I/O Control unit released at initiation I/O task is under control of ERP I/O task has been reset I/O initiated via DIAGNOSE instruction
1*2 IOBLOK status Unrecoverable error in this I/O operation IOBLOK queued pending completion of a MSS cylinder fault Path is fixed, use IOBRADD value
This is a mini-IOBLOK DASD channel program has seek to alternate
track
Processing CC 3, not available
Processing CC 2! channel busy
Processing CC 1, CSW stored
Processing I/O interrupt
section 1. CP Data Areas and Control Blocks 25

Page of SY20-0884-3 As Updated Aug. 1, 1979 by TNL SN25-0497 IOBLOK Hexadecimal
Displacement
------------ 4 8
C 10 12
14
18
1C 20 24
28 30 34
38
39
3A
3B
3C
12
Field
Name
IOBLINK DS IOBFPNT DS IOBBPNT DS
1F
1F
1F
Field Description, Contents, Meaning
Pointer for multipath IOBLOK chain
Pointer to next IOBLOK in queue
Pointer to previous IOBLOK in queue IOBMSIZE EQU (*-IOBLOK) /8 Multiple path IOBLOK size in doublewords IOBCYL DS IOBVADD DS IOBMISC DS lOB USER DS IOBIRA DS IOBCAW DS IOBRCAW DS IOBCSW DS IOBIOER DS IOBMISC2 DS IOBSPEC DS ,gefined IOBTIO EQU IOBHIO EQU IOBSIOF EQU IOBIMSTK EQU IOBUNSL EQU IOBCOPY EQU IOBSENS EQU IOBTRPND EQU IOBSPEC2 DS
1H
1H
1F
1F
1F
1F
1F
1D
1F
1F 1X in IOBSPE£ X'80' X'40' X'20' X'10' X'08' X'04' X'02' X'01' 1X Bits defined in IOBSPEC2 IOBWRAP EQU --X'80'---- IOBCLN EQU X'40' IOBUNREL EQU X'20' IOBUC EQU IOBSNSIO EQU IOBREL EQU IOBSPEC3 DS X'10' X'08' X'04' 1X Bil§ de!ined in IOBSPEC3 IOBSENSE EQU --X'80'---- IOBCUE EQU X'20' IOBVCUE EQU X'10' IOBRSV2 DS IOBCUBSY DS 1X 1F IVI"")'\ \A "' .... I DASD --seek cylinder for this IOBLOK Virtual device address Use varies according to caller
Pointer to VMBLOK of user IOBLOK interrupt return address
Pointer to CCW chain
Pointer to restart CCW chain
Real CSW for I/O operation
Pointer to IOERBLOK with sense byte Use varies according to caller 1*3 IOBLOK special requests flag IOBLOK request for a TIO IOBLOK request for a HIO Virtual SIO fast release
Shut down SDR function IOBLOK resulting from unsolicited interrupt I/O block associated with a COpy request
Sense operation for COpy request Virtual trace pending on this I/O block 1*4 IOBLOK special requests flag second byte
Input/output task for AUTOPOLL wrap list VDEVBLOK locked when CCW got control
Input/output task contains release, DMKUNT must process Unit check status
Normal sense operation in progress
Channel program contains CP release IOBLOK special requests flag third byte
Do not execute sense operation on hardware
Special queue IOBLOK for SPM V=R Virtual queue IOBLOK for SPM V=R Reserved for IBM use
Forward Pointer for control unit busy IOBLOKs IOBSIZE EQU (*-IOBLOK)/8 IOBLOK size in doublewords (X'08') £E IOBLOKs ORG IOBVADD IOBRCNT DS 1H Retry count
26 IBM VM/370 Data Areas and control Block Logic