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