DRWBK Back to Index page
 
Prolog 
Control Block Contents 
   DRWBK DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  DRWBK Prolog Top of page
 
 NAME       : HCPDRWBK
 DESCRIPTION: DASD Read/Write Channel Program Block
 DSECT      : DRWBK
 FUNCTION   : This DSECT maps the channel program created
              to process a *BLOCKIO or diagnose A4 I/O\request
 LOCATED BY : DVICHPRG field in HCPDVIOP
 CREATED BY : HCPDPSRW
 DELETED BY : HCPDPSCU
 SERIALIZED : Unique task execution
              VMDBK dispatch lock.
              The chain of DVIOPS is protected by the
              BLKIO lock, in HCPBLKIO
 RELOCATION CONSIDERATIONS : None
 
 
  DRWBK Control Block Content Top of page
 

 DRWBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure DRWBK DASD Read/Write Channel Program Block 0000 0 Dbl-Word 8 DRWCHPRG (0) Channel program segment 0000 0 Dbl-Word 8 DRWSEEK SEEK CCW 0008 8 Dbl-Word 8 DRWSSECT SET SECTOR CCW 0010 16 Dbl-Word 8 DRWSRCH SEARCH ID CCW 0018 24 Dbl-Word 8 DRWTIC1 TIC CCW 0020 32 Dbl-Word 8 DRWRDWR READ/WRITE CCW 0028 40 Dbl-Word 8 DRWTIC2 TIC CCW 00000030 DRWCHPSZ *-DRWCHPRG 0030 48 Bitstring 12 DRWDATA (0) Data area portion of channel program Segment 0030 48 Bitstring 6 DRWSKARG (0) SEEK argument (BBCCHH) 0030 48 Bitstring 2 DRWSKBIN SEEK: bin (BB) number 0032 50 Bitstring 2 DRWSKCYL SEEK: cylinder (CC) number ..11 ..1. DRWSKCCH 00004 DRWSKCYL,4 SEEK: ccccCCCH field 0034 52 Bitstring 2 DRWSKHED SEEK: head/track (HH) number 0036 54 Bitstring 5 DRWSRCAR (0) SEARCH ID equal argument (CCHHR) 0036 54 Bitstring 2 DRWSRCYL SEARCH: cylinder (CC) number ..11 .11. DRWSRCCH 00004 DRWSRCYL,4 SEARCH: ccccCCCH field 0038 56 Bitstring 3 DRWSRHHR (0) SEARCH: head + record (HHR) 0038 56 Bitstring 2 DRWSRHED SEARCH: head/track (HH) number 003A 58 Bitstring 1 DRWSRREC SEARCH: record (R) number 003B 59 Bitstring 1 DRWSECTR SET SECTOR: sector number 003C 60 Signed 4 * Reserved for IBM use 00000040 DRWBSIZE *-DRWCHPRG Byte size of channel program (CCWs plus data area) 00000008 DRWSIZE (DRWBSIZE+7)/8 Doubleword size of channel program (CCWs plus data area) 0040 64 Dbl-Word 8 DRWNXTSG (0) Start of next channel program segment
 
 
  DRWBK Storage Layout Top of page
 
          
*** DRWBK - DASD Read/Write Channel Program Block
*
*     +-------------------------------------------------------+
*   0 |                       DRWSEEK                         |
*     +-------------------------------------------------------+
*   8 |                       DRWSSECT                        |
*     +-------------------------------------------------------+
*  10 |                       DRWSRCH                         |
*     +-------------------------------------------------------+
*  18 |                       DRWTIC1                         |
*     +-------------------------------------------------------+
*  20 |                       DRWRDWR                         |
*     +-------------------------------------------------------+
*  28 |                       DRWTIC2                         |
*     +-------------+-------------+-------------+-------------+
*  30 |  DRWSKBIN   |  DRWSKCYL   |  DRWSKHED   |  DRWSRCYL   |
*     +-------------+------+------+-------------+-------------+
*  38 |  DRWSRHED   |:SRREC|:SECTR|///////////////////////////|
*     +-------------+------+------+---------------------------+
*
*** DRWBK - DASD Read/Write Channel Program Block
 
 
  DRWBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
DRWBSIZE       003C 00000040
DRWCHPRG       0000
DRWCHPSZ       0028 00000030
DRWDATA        0030
DRWNXTSG       0040
DRWRDWR        0020
DRWSECTR       003B
DRWSEEK        0000
DRWSIZE        003C 00000008
DRWSKARG       0030
DRWSKBIN       0030
DRWSKCCH       0032 32
DRWSKCYL       0032
DRWSKHED       0034
DRWSRCAR       0036
DRWSRCCH       0036 36
DRWSRCH        0010
DRWSRCYL       0036
DRWSRHED       0038
DRWSRHHR       0038
DRWSRREC       003A
DRWSSECT       0008
DRWTIC1        0018
DRWTIC2        0028
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:49:46 EDT.
Copyright IBM Corporation, 1990, 2022