Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### DBCWK

Prolog

Control Block Contents
DBCWK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### DBCWK Prolog

     NAME       : HCPDBCWK
     DESCRIPTION: DASD Block I/O work block
     DSECT      : DBCWK
     FUNCTION   : Contains information specific to DASD block
                  I/O requests.  It is basically a work area
                  for HCPDBC and it is also now used as the control
                  block to represent the current state of a
                  particular Diagnose 250 or *BLOCKIO (request).
                  (The SNDBK and BRQBK used to fulfill these
                  roles, any fields in those control blocks
                  now reside here).
                  Since a number fields are specific to the particular
                  i/o request, there is an overlay portion of this control
                  block at label DBCSPECL.  The overlays are defined in
                  here and there is an overlay for each type of i/o.
     LOCATED BY : This is pointed to by R13 in all of the
                  block i/o handlers (HCPBIM, HCPBIR, HCPDGB
                  HCPBID, HCPDGD, HCPDBC and HCPDBD).
     CREATED BY : HCPDGB (Diag A4 handling)
                  HCPBIM (*BLOCKIO handling)
                  HCPBID (Diag 250 handling)
                  HCPDGD (Diag 18  handling)
     DELETED BY : HCPDGB (Diag A4 handling)
                  HCPBIM (*BLOCKIO handling)
                  HCPBID or HCPBIR (Diag 250 handling)
                  HCPDGD (Diag 18  handling)
     COMMENTS   : The DBCWK area contains one BPLBK (DBCSINGL) and one
                  IPARML Reply (DBCPARML).  If the size of either of
                  these control blocks changes, then DBCSINGL and
                  DBCPARML should be updated accordingly.

#### DBCWK Control Block Content

#### DBCWK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      DBCWK          DASD Block I/O work block
    0000    0 Dbl-Word     8 * (64)         Space for standard saveBK
    0200  512 Dbl-Word     8 DBCIASIT       I-ASIT for the
                                            SBIOP/SBILIST/BPLBK and guest
                                            buffers.
          Work area can be used as a temporary save area by any
          routine that needs to save something temporarily.
          The general rule of thumb is that a value stored in
          DBCWORK is only used within the subroutine that stored it
          there, any exceptions to this rule are noted in the code.
    0208  520 Dbl-Word     8 DBCWORK (0)    Temporary work area
    0208  520 Signed       4 DBCWORK1       Work word 1
    020C  524 Signed       4 DBCWORK2       Work word 2
    0210  528 Signed       4 DBCWORK3       Work word 3
    0214  532 Signed       4 DBCWORK4       Work word 4
          The following 4 bytes (1 word) are used to hold various
          processing bits common to all types of block i/o.
    0218  536 Bitstring    1 DBCSWTCH       Flags for processing control
              1... ....      DBCGOOD        X'80' At least one good i/o
              .1.. ....      DBCNSTD        X'40' Nonstandard block size
              ..1. ....      DBCNOCAR       X'20' No caching requested
              ...1 ....      DBCWRITE       X'10' Type of I/O 1 for read, 0
                                            for write
              .... 1...      DBCCACC        X'08' Cache access held
              .... .1..      DBCINCAC       X'04' This I/O operation is no
                                            longer eligible for caching
              .... ..1.      DBCARMOD       X'02' In AR Mode
              .... ...1      DBCPRIM        X'01' Parameter list in primary
    0219  537 Bitstring    1 DBCSWTC2       More flags for processing
              1... ....      DBCNOTEL       X'80' DBCNOTEL Not eligible for
                                            cache
              .1.. ....      DBCBLKER       X'40' DBCBLKER Found block in
                                            error
              ..1. ....      DBCREPLP       X'20' DBCREPLP Must replace Parm
                                            List
              ...1 ....      DBCCOPYP       X'10' DBCCOPYP Made copy of Parm
                                            list
              .... 1...      DBCASYNC       X'08' DBCASYNC Asynchronous
                                            blockio
              .... .1..      DBCDG250       X'04' DBCDG250 DIAG 250 i/o
              .... ..1.      DBCBLKIO       X'02' DBCBLKIO *BLOCKIO i/o
              .... ...1      DBCDGA4        X'01' DBCDGA4 DIAGA4 i/o
          DBCGKEY  has key for storage protection checks
    021A  538 Bitstring    1 DBCGKEY        Storage key
    021B  539 Bitstring    1 DBCSWTC4       More processing bits
              1... ....      DBCGLDEL       X'80' DBCGLDEL All track deletion
                                            req.
              .1.. ....      DBCNOREL       X'40' DBCNOREL Don't release on
                                            read
              ..1. ....      DBCRDCPY       X'20' DBCRDCPY Read access must
                                            copy data
              ...1 ....      DBCARGST       X'10' DBCARGST Guest in AR mode
              .... 1...      DBCSAWWR       X'08' DBCSAWWR At least 1 write
                                            in req.
              .... .1..      DBCWFAIL       X'04' DBCWFAIL At least 1 write
                                            failed
              .... ..1.      DBCXSTOR       X'02' DBCXSTOR Cache block on
                                            XSTOR
              .... ...1      DBCDIDIO       X'01' DBCDIDIO Did I/O for this
                                            request
    021C  540 Signed       4 DBCSAV         original SAVBK address
          The DBCHALET is used for the block list control block
          for the particular type of block i/o request.
    0220  544 Signed       4 DBCHALET       ALET for guest space (CP)
    0224  548 Signed       4 DBCEALET       Guest version of ALET.
    0228  552 Signed       4 DBCERET        Return address save
    022C  556 Signed       4 DBCERET2       2'nd level return address save
    0230  560 Signed       4 DBCDPSBK       DPSBK Address
    0234  564 Signed       4 DBCANCHR       BIOPG page list anchor
          The following fields used to be in a separate control
          block called a DVCPL.  They are now placed here to
          avoid having to load up its address all the time.
    0238  568 Signed       4 DBCHFRST       Beginning of DVIENTRY linked list
    023C  572 Signed       4 DBCHLAST       End of DVIENTRY linked list
    0240  576 Address      4 DBCOPPTR       Beginning of DVIOP linked list
    0244  580 Signed       4 DBCTFRST       DVTRK (tracks accessed) list
    0248  584 Address      4 DBCLCKAD       Address of lock word
    024C  588 Signed       4 DBCMAXCH       Max channel program size
    0250  592 Signed       4 DBCKEY         Key save area
    0254  596 Signed       4 *              Reserved for future IBM use
    0258  600 Dbl-Word     8 DBCBKNUM       Block number save area
    0260  608 Signed       4 DBCDVC         DBC/DBE - ptr to DVIENTRY DGB/DGD
                                            - ptr to DVIOP
    0264  612 Signed       4 DBCTKPTR       Pointer to previous DVTRK
    0268  616 Signed       4 DBCRTRAK       Relative track save area
    026C  620 Signed       4 DBCTCHBK       Last Read TCHBK Addr
    0270  624 Signed       4 DBCMXENT       Max entry count
    0274  628 Signed       4 DBCERRAD       Address where a host storage
                                            error occurred on parameter list.
          The following fields are the CDATA word and the
          DPSBK information from the currently-in-use track,
          by that we mean that it is the one we will next try
          to copy data to/from.
    0278  632 Signed       4 DBCTKDAT (0)   Data for current track
    0278  632 Signed       4 DBCCDATA (0)   TCHBK save
    0278  632 Signed       2 DBCVCYL        Virtual cylinder
    027A  634 Bitstring    1 DBCFSTRN       First record number
    027B  635 Bitstring    1 DBCLOWRN       Low record number
    027C  636 Signed       4 * (0)
    027C  636 Bitstring    1 *              Reserved for IBM use
    027D  637 Bitstring    3 DBCDPSTF (0)   DPSBK stuff we care about
    027D  637 Bitstring    1 DBCHIRN        Highest record number
    027E  638 Signed       2 DBCTKSIZ       Blocksize of track
              00000002       DBCTKLEN       (*-DBCTKDAT+3)/4 Size in words of
                                            track data
          The following field  is the read copy of the data.
          We only have 1 read track accessed at any given time,
          yet for *BLOCKIO and DIAG 250 we may have mixed reads
          and writes.  So if we get write access to a track, then we
          copy the read data to this temporary save area.  Then,
          if we later read from the current read track, then we
          can just copy the data back instead of going through a
          re-access of the track.
    0280  640 Signed       4 DBCRDSAV (2)   Read save area
    0288  648 Signed       4 DBCBLKCT       Remember block count
    028C  652 Signed       4 DBCRC          Return code save area
    0290  656 Signed       2 DBCBLKSZ       Block size
    0292  658 Signed       2 DBCHSID        Hash id for cache
    0294  660 Signed       2 DBCOFSET       OFFSET into track
    0296  662 Signed       2 DBCDBICT       Count of DBIRQ blocks sent to
                                            HCPIOS
    0298  664 Signed       4 DBCDVIAD       Pointer to next DVIOP to schedule
                                            for these i/o oper.
    029C  668 Address      4 DBCNEXT        Pointer to next DBCWK for this
                                            virtual device
    02A0  672 Signed       4 DBCRELRT       Release return address
    02A4  676 Signed       4 DBCMALET       ALET FOR MDC address space for
                                            last track accessed
    02A8  680 Signed       4 * (0)
    02A8  680 Bitstring    1 DBCSWTC5       More processing bits
              1... ....      DBCDG18        X'80' DBCDG18 Processing a Diag
                                            X'18'
    02A9  681 Bitstring    1 *              Reserved for IBM use
    02AA  682 Signed       2 DBCTMPH        Tempary half word savearea
    02AC  684 Signed       4 *              Reserved for IBM use
    02B0  688 Dbl-Word     8 DBCSPECL (0)
    02B0  688 Dbl-Word     8 * (10)         Overlay area, note that this
                                            leaves room for service.
              00000060       DBCWKLEN       (*-DBCWK+7)/8 Size in double
                                            words
          DIAGNOSE 18  Specific fields Are overlayed at label
          DBCSPECL.
    02B0  688 Dbl-Word     8 DBCSVCCW       Host copy of CCW
          DBCARGSV has BBCCHH of first SEEK in CCW program and the
          relocated CC address for the minidisk.
    02B8  696 Dbl-Word     8 DBCARGSV (0)   First SEEK arguments
    02B8  696 Signed       2 DBCARGBB       BB portion of seek
    02BA  698 Signed       2 DBCARGCC       CC portion of seek
    02BC  700 Signed       2 DBCARGHH       HH portion of seek
    02BE  702 Signed       2 DBCCYLSV       Relocated CC of seek
          DBCNXTSV has BBCCHH of latest SEEK in CCW program
    02C0  704 Dbl-Word     8 DBCNXTSV (0)   Latest SEEK arguments
    02C0  704 Signed       2 DBCNXTBB       BB portion of seek
    02C2  706 Signed       2 DBCNXTCC       CC portion of seek
    02C4  708 Signed       2 DBCNXTHH       HH portion of seek
    02C6  710 Signed       2 *              Reserved for IBM use
          DBCORIEN has the latest record orientation information
          in it.   It has the CCHHR of the last record that we read
          from the cache.
    02C8  712 Bitstring    5 DBCORIEN (0)   Latest SIDE arguments
    02C8  712 Signed       2 DBCORICC       CC of SIDE
    02CA  714 Signed       2 DBCORIHH       HH of SIDE
    02CC  716 Bitstring    1 DBCORIR        R of SIDE
    02CD  717 Bitstring    1 DBC18SWT       More flags
              1... ....      DBCFIRST       X'80' DBCFIRST Working on first
                                            CCW
              .1.. ....      DBCBUSYV       X'40' DBCBUSYV Made the VDEV busy
              ..1. ....      DBCSILI        X'20' DBCSILI SILI bit on
              ...1 ....      DBCMIXED       X'10' DBCMIXED Mixed blocksizes
                                            found
              .... 1...      DBCREMOV       X'08' DBCREMOV Can remove
                                            DVIENTRYs
              .... .1..      DBCSTD         X'04' DBCSTD Track is standard
              .... ..1.      DBCEOT         X'02' DBCEOT Reached End of Track
    02CE  718 Signed       2 DBCMAXSZ       Max block size found
    02D0  720 Signed       4 DBCIORAD       IORBK save address
    02D4  724 Signed       4 DBCGCCW        Guest CCW Address
    02D8  728 Signed       4 DBCCCWCT       CCW count
    02DC  732 Signed       4 DBCCYLTK       Relative track for cyl
    02E0  736 Signed       4 DBCSEKPT       Last SearchID DVIENTRY
    02E4  740 Signed       4 DBCCPSPT       Last C.P.S. Pointer
    02E8  744 Signed       4 DBCTKHED       Track pointer
    02EC  748 Signed       4 DBC18RC        Diag 18 return code
    02F0  752 Signed       4 * (4)          Reserved for IBM use
          DIAGNOSE A4  Specific fields Are overlayed at label
          DBCSPECL.
    02B0  688 Bitstring    1 DBCA4SWT       More flags
              1... ....      DBCVDEV        X'80' DBCVDEV Got the VDEV lock
                                            to be copied back to guest
                                            storage.
              .1.. ....      DBCBUSY        X'40' DBCBUSY We turned on
                                            VDEVBUSY
              ..1. ....      DBCREPS        X'20' DBCREPS SBIOP must be
                                            replaced on exit
              ...1 ....      DBCFORMT       X'10' DBCFORMT Request type
                                            format
              .... 1...      DBCINIOR       X'08' DBCINIOR Initialized IORBK
              .... .1..      DBCCOPYS       X'04' DBCCOPYS SBIOP was copied
                                            to host stor
              .... ..1.      DBCQDSK        X'02' DBCQDSK Have Vdisk I/O lock
              .... ...1      DBCBKOUT       X'01' DBCBKOUT End-user breakout
                                            enabled
    02B1  689 Bitstring    1 DBCARNUM       ARx access register
    02B2  690 Bitstring    1 DBCLPM         Guest LPM
    02B3  691 Bitstring    1 *              Reserved for IBM use
    02B4  692 Signed       4 DBCAR9         Save for current ALET
    02B8  696 Signed       4 DBCPROG        Prog check operand
    02BC  700 Signed       4 DBCIORBK       IORBK save address
    02C0  704 Signed       4 DBCBLKPR       Blocks processed
    02C4  708 Signed       4 DBCSBIOP       Address of SBIOP
    02C8  712 Signed       4 DBCGADDR       Guest addr of SBIOP
    02CC  716 Signed       4 *              Reserved for IBM use
    02D0  720 Signed       4 DBCGLIST       SBILIST guest address
    02D4  724 Signed       4 * (11)         Reserved for IBM use
          DIAGNOSE A4 Format specific fields are overlayed at label
          DBCGLIST.
    02D0  720 Dbl-Word     8 DBCFBLKS       SBIFBLKS
    02D8  728 Dbl-Word     8 DBCDIDBK       SBIDIDBK
    02E0  736 Dbl-Word     8 DBCFDATA       SBIFDATA
    02E8  744 Dbl-Word     8 DBCLBA         SBILBA
    02F0  752 Signed       4 * (4)          Reserved for IBM use
          DIAGNOSE 250 Specific fields are overlayed at label
          DBCSPECL.
          The following is an address space buffer. It holds the
          latest address space info on a guest buffer specified in
          the BELBK entry.  I.E. It holds the latest BELBALET and
          the associated things that we care about.  A
          non-zero entry indicates that we have access to the data
          space containing the buffer.  A zero entry means that there
          is no address space attached for a given BELBK entry.
    02B0  688 Dbl-Word     8 DBCBASIT       BELBK I-asit Address
    02B8  696 Signed       4 DBCBKIBK       BKIBK address
    02BC  700 Address      4 DBCHALBK       Address of the host-ART lookaside
                                            block containing the ALET/i-ASIT
                                            pairs associated with the data
                                            buffers in the BELBK entries.
    02C0  704 Bitstring    1 DBCDOPER       Operation field for the DIAG
                                            X'250' request
              1... ....      DBCABSET       X'80' Abort exit was established
              .1.. ....      DBCABORT       X'40' Abort exit was driven
              ..1. ....      DBCASYRQ       X'20' Guest requested
                                            asynchronous processing.
              ...1 ....      DBCBYPAS       X'10' Guest requested that we
                                            bypass minidisk cache
              .... 1...      DBCBELST       X'08' The BELBK could not be
                                            stored for the completion of an
                                            asynchronous request.
              .... .1..      DBC64BIT       X'04' Diag 250 guest used large
                                            fields in BIOPL and BELBK.
    02C1  705 Bitstring    1 DBCFLAGS       More processing flags
              1... ....      DBCBELGT       X'80' DBCBELGT Used GETST to get
                                            BELBK
              .1.. ....      DBCGTHAL       X'40' DBCGTHAL Used GETST to get
                                            HALBK
    02C2  706 Bitstring    1 DBC250RC       Return code for request
                                            processing
              .... ....      DBCRC00        X'00' A synchronous request was
                                            successful (either scheduled and
                                            completed, or from cache) or an
                                            asynchronous request was
                                            successfully satisfied from
                                            cache.
              .... 1...      DBCRC08        X'08' An asynchronous request was
                                            initiated (all or part of the I/O
                                            was scheduled).
              .... 11..      DBCRC12        X'0C' A request was partially
                                            successful. If asynchronous, part
                                            of the request was satisfied from
                                            cache, but an error occurred
                                            preventing the entire request
                                            from completing successfully.
              ..1. 1...      DBCRC40        X'28' All of the BELBK entries
                                            were in error, or all DVIOPs were
                                            in error.
              ..1. 11..      DBCRC44        X'2C' Remove or reset terminated
                                            a synchronous request.
              ..11 ....      DBCRC48        X'30' A synchronous request was
                                            terminated by the user (the abort
                                            exit was driven).
              1111 1111      DBCRC255       X'FF' A catastrophic error (abend
                                            condition) occurred. Some I/O may
                                            have been scheduled or done.
    02C3  707 Bitstring    1 *              Reserved for IBM use
    02C4  708 Signed       2 DBCBELCT       Number of entries in the block
                                            I/O entry list
    02C6  710 Signed       2 *              Reserved for IBM use
    02C8  712 Signed       4 *              Reserved for IBM use
    02CC  716 Address      4 DBCBELBK       31 bit host logical address of
                                            the block I/O entry list.
    02D0  720 Address      8 DBCGBELA       64 bit guest absolute address of
                                            the block I/O entry list.
    02D8  728 Dbl-Word     8 DBCIPARM (0)   Interruption parameter, if this
                                            is an asynchronous request.
    02D8  728 Signed       4 *              High half of 64 bit PARM
    02DC  732 Signed       4 DBCIPARM32     Low half of 64 bit PARM or 32 bit
                                            PARM
    02E0  736 Dbl-Word     8 DBCOFFCP       Offset for block number - this is
                                            a copy of BKIOFFCP
    02E8  744 Signed       4 * (6)          Reserved for IBM use
         **BLOCKIO     Specific fields are overlayed at label
          DBCSPECL.
            DBCSINGL contains a BPLBK, so any changes to the BPLBK
            size affect this field.
            NOTES      :  Currently the BPLBK is 4F, but the last 1F is
                   unused, so using 3F for DBCSINGL works (and is
                   all we can fit in DBCSPECL at this time).
    02B0  688 Signed       4 DBCSINGL (3)   Storage for a single block I/O
                                            version of the multiple block I/O
                                            parameter list Mapped by HCPBPLBK
    02BC  700 Signed       4 DBCBLKAD       BLKIO address
    02C0  704 Bitstring    1 DBCBOPER       Operation field for SEND Request
              1... ....      DBCMONO        X'80' DBCMONO Indicate Single BLK
                                            SEND REQ Protocol
              .1.. ....      DBCMULTI       X'40' DBCMULTI Indicate Multi BLK
                                            SEND REQ Protocol
              ..1. ....      DBCIWAIT       X'20' DBCIWAIT Indicate waiting
                                            for I/O interrupts
              ...1 ....      DBCSYNC        X'10' DBCSYNC Guest request is
                                            synchronous
              .... 1...      DBCGOTBL       X'08' DBCGOTBL got storage for
                                            blockio list
              .... .1..      DBCSEXIT       X'04' DBCSEXIT Exitted to caller
                                            already DBCBLKRC codes are
                                            defined in HCPBIM
    02C1  705 Bitstring    1 DBCBLKRC       IUCV Reply Return Code
    02C2  706 Signed       2 DBCSSHCT       Number of real SSCH issued to
                                            handle this send request.
    02C4  708 Signed       4 DBCMSGID       IUCV message id
    02C8  712 Signed       4 DBCTRGCL (0)   IUCV target class
    02C8  712 Bitstring    3 *              IUCV target class
    02CB  715 Bitstring    1 DBCBLKRQ       Blockio service request
              1... ....      DBCBLKNC       X'80' DBCBLKNC Bypass MDC
                                            processing
              .... ..11      DBCBLKMB       X'03' DBCBLKMB Multi-block
                                            request
              .... ..1.      DBCBLKRD       X'02' DBCBLKRD Single block read
              .... ...1      DBCBLKWR       X'01' DBCBLKWR Single block write
    02CC  716 Address      4 DBCPLADR       Address of the multiple block
                                            parameter list in host logical
                                            storage
    02D0  720 Signed       4 DBCGPLST       Guest address of the multiple
                                            block
            DBCPARML houses an IPARML, so any changes to the IPARML
            size affect this field.
    02D4  724 Bitstring   40 DBCPARML       IUCV reply parameter list
              00FFFF7C       DBCTCMSK       X'FFFFFFFF'-(DBCBLKNC+DBCBLKMB)
                                            Mask to validate DBCTRGCL (IUCV
                                            target class)
    02FC  764 Signed       2 DBCPLCNT       Count of elements in the multiple
                                            block parameter list
    02FE  766 Signed       2 DBCPLSIZ       Size of the multiple block
                                            parameter list in bytes

#### DBCWK Storage Layout

    *** DBCWK - DASD Block I/O work block
    *
    *     +-------------------------------------------------------+
    *   0 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 200 |                       DBCIASIT                        |
    *     +---------------------------+---------------------------+
    * 208 |         DBCWORK1          |         DBCWORK2          |
    *     +---------------------------+---------------------------+
    * 210 |         DBCWORK3          |         DBCWORK4          |
    *     +------+------+------+------+---------------------------+
    * 218 |:SWTCH|:SWTC2|:GKEY |:SWTC4|          DBCSAV           |
    *     +------+------+------+------+---------------------------+
    * 220 |         DBCHALET          |         DBCEALET          |
    *     +---------------------------+---------------------------+
    * 228 |         DBCERET           |         DBCERET2          |
    *     +---------------------------+---------------------------+
    * 230 |         DBCDPSBK          |         DBCANCHR          |
    *     +---------------------------+---------------------------+
    * 238 |         DBCHFRST          |         DBCHLAST          |
    *     +---------------------------+---------------------------+
    * 240 |         DBCOPPTR          |         DBCTFRST          |
    *     +---------------------------+---------------------------+
    * 248 |         DBCLCKAD          |         DBCMAXCH          |
    *     +---------------------------+---------------------------+
    * 250 |          DBCKEY           |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 258 |                       DBCBKNUM                        |
    *     +---------------------------+---------------------------+
    * 260 |          DBCDVC           |         DBCTKPTR          |
    *     +---------------------------+---------------------------+
    * 268 |         DBCRTRAK          |         DBCTCHBK          |
    *     +---------------------------+---------------------------+
    * 270 |         DBCMXENT          |         DBCERRAD          |
    *     +-------------+------+------+------+------+-------------+
    * 278 |  DBCVCYL    |:FSTRN|:LOWRN|//////|:HIRN |  DBCTKSIZ   |
    *     +-------------+------+------+------+------+-------------+
    * 280 |                       DBCRDSAV                        |
    *     +---------------------------+---------------------------+
    * 288 |         DBCBLKCT          |          DBCRC            |
    *     +-------------+-------------+-------------+-------------+
    * 290 |  DBCBLKSZ   |  DBCHSID    |  DBCOFSET   |  DBCDBICT   |
    *     +-------------+-------------+-------------+-------------+
    * 298 |         DBCDVIAD          |         DBCNEXT           |
    *     +---------------------------+---------------------------+
    * 2A0 |         DBCRELRT          |         DBCMALET          |
    *     +------+------+-------------+---------------------------+
    * 2A8 |:SWTC5|//////|  DBCTMPH    |///////////////////////////|
    *     +------+------+-------------+---------------------------+
    * 2B0 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 300
    *
    *** DBCWK - DASD Block I/O work block

    *** Overlay for DBCSPECL in DBCWK
    *
    *     +-------------------------------------------------------+
    * 2B0 |                       DBCSVCCW                        |
    *     +-------------+-------------+-------------+-------------+
    * 2B8 |  DBCARGBB   |  DBCARGCC   |  DBCARGHH   |  DBCCYLSV   |
    *     +-------------+-------------+-------------+-------------+
    * 2C0 |  DBCNXTBB   |  DBCNXTCC   |  DBCNXTHH   |/////////////|
    *     +-------------+-------------+------+------+-------------+
    * 2C8 |  DBCORICC   |  DBCORIHH   |:ORIR |:18SWT|  DBCMAXSZ   |
    *     +-------------+-------------+------+------+-------------+
    * 2D0 |         DBCIORAD          |         DBCGCCW           |
    *     +---------------------------+---------------------------+
    * 2D8 |         DBCCCWCT          |         DBCCYLTK          |
    *     +---------------------------+---------------------------+
    * 2E0 |         DBCSEKPT          |         DBCCPSPT          |
    *     +---------------------------+---------------------------+
    * 2E8 |         DBCTKHED          |         DBC18RC           |
    *     +---------------------------+---------------------------+
    * 2F0 |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 300
    *
    *** Overlay for DBCSPECL in DBCWK

    *** Overlay for DBCSPECL in DBCWK
    *
    *     +------+------+------+------+---------------------------+
    * 2B0 |:A4SWT|:ARNUM|DBCLPM|//////|          DBCAR9           |
    *     +------+------+------+------+---------------------------+
    * 2B8 |         DBCPROG           |         DBCIORBK          |
    *     +---------------------------+---------------------------+
    * 2C0 |         DBCBLKPR          |         DBCSBIOP          |
    *     +---------------------------+---------------------------+
    * 2C8 |         DBCGADDR          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 2D0 |         DBCGLIST          |///////////////////////////|
    *     +---------------------------+///////////////////////////|
    * 2D8 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 300
    *
    *** Overlay for DBCSPECL in DBCWK

    *** Overlay for DBCGLIST in DBCWK
    *
    *     +-------------------------------------------------------+
    * 2D0 |                       DBCFBLKS                        |
    *     +-------------------------------------------------------+
    * 2D8 |                       DBCDIDBK                        |
    *     +-------------------------------------------------------+
    * 2E0 |                       DBCFDATA                        |
    *     +-------------------------------------------------------+
    * 2E8 |                        DBCLBA                         |
    *     +-------------------------------------------------------+
    * 2F0 |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 300
    *
    *** Overlay for DBCGLIST in DBCWK

    *** Overlay for DBCSPECL in DBCWK
    *
    *     +-------------------------------------------------------+
    * 2B0 |                       DBCBASIT                        |
    *     +---------------------------+---------------------------+
    * 2B8 |         DBCBKIBK          |         DBCHALBK          |
    *     +------+------+------+------+-------------+-------------+
    * 2C0 |:DOPER|:FLAGS|:250RC|//////|  DBCBELCT   |/////////////|
    *     +------+------+------+------+-------------+-------------+
    * 2C8 |///////////////////////////|         DBCBELBK          |
    *     +---------------------------+---------------------------+
    * 2D0 |                       DBCGBELA                        |
    *     +---------------------------+---------------------------+
    * 2D8 |///////////////////////////|        DBCIPARM32         |
    *     +---------------------------+---------------------------+
    * 2E0 |                       DBCOFFCP                        |
    *     +-------------------------------------------------------+
    * 2E8 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 300
    *
    *** Overlay for DBCSPECL in DBCWK

    *** Overlay for DBCSPECL in DBCWK
    *
    *     +-------------------------------------------------------+
    * 2B0 |                       DBCSINGL                        |
    *     |                           +---------------------------+
    * 2B8 |                           |         DBCBLKAD          |
    *     +------+------+-------------+---------------------------+
    * 2C0 |:BOPER|:BLKRC|  DBCSSHCT   |         DBCMSGID          |
    *     +------+------+------+------+---------------------------+
    * 2C8 |////////////////////|:BLKRQ|         DBCPLADR          |
    *     +--------------------+------+---------------------------+
    * 2D0 |         DBCGPLST          |                           |
    *     +---------------------------+                           |
    * 2D8 |                                                       |
    *     =                       DBCPARML                        =
    *     |                           +-------------+-------------+
    * 2F8 |                           |  DBCPLCNT   |  DBCPLSIZ   |
    *     +---------------------------+-------------+-------------+
    * 300
    *
    *** Overlay for DBCSPECL in DBCWK

#### DBCWK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    DBCABORT       02C0 40
    DBCABSET       02C0 80
    DBCANCHR       0234
    DBCARGBB       02B8
    DBCARGCC       02BA
    DBCARGHH       02BC
    DBCARGST       021B 10
    DBCARGSV       02B8
    DBCARMOD       0218 02
    DBCARNUM       02B1
    DBCAR9         02B4
    DBCASYNC       0219 08
    DBCASYRQ       02C0 20
    DBCA4SWT       02B0
    DBCBASIT       02B0
    DBCBELBK       02CC
    DBCBELCT       02C4
    DBCBELGT       02C1 80
    DBCBELST       02C0 08
    DBCBKIBK       02B8
    DBCBKNUM       0258
    DBCBKOUT       02B0 01
    DBCBLKAD       02BC
    DBCBLKCT       0288
    DBCBLKER       0219 40
    DBCBLKIO       0219 02
    DBCBLKMB       02CB 03
    DBCBLKNC       02CB 80
    DBCBLKPR       02C0
    DBCBLKRC       02C1
    DBCBLKRD       02CB 02
    DBCBLKRQ       02CB
    DBCBLKSZ       0290
    DBCBLKWR       02CB 01
    DBCBOPER       02C0
    DBCBUSY        02B0 40
    DBCBUSYV       02CD 40
    DBCBYPAS       02C0 10
    DBCCACC        0218 08
    DBCCCWCT       02D8
    DBCCDATA       0278
    DBCCOPYP       0219 10
    DBCCOPYS       02B0 04
    DBCCPSPT       02E4
    DBCCYLSV       02BE
    DBCCYLTK       02DC
    DBCDBICT       0296
    DBCDGA4        0219 01
    DBCDG18        02A8 80
    DBCDG250       0219 04
    DBCDIDBK       02D8
    DBCDIDIO       021B 01
    DBCDOPER       02C0
    DBCDPSBK       0230
    DBCDPSTF       027D
    DBCDVC         0260
    DBCDVIAD       0298
    DBCEALET       0224
    DBCEOT         02CD 02
    DBCERET        0228
    DBCERET2       022C
    DBCERRAD       0274
    DBCFBLKS       02D0
    DBCFDATA       02E0
    DBCFIRST       02CD 80
    DBCFLAGS       02C1
    DBCFORMT       02B0 10
    DBCFSTRN       027A
    DBCGADDR       02C8
    DBCGBELA       02D0
    DBCGCCW        02D4
    DBCGKEY        021A
    DBCGLDEL       021B 80
    DBCGLIST       02D0
    DBCGOOD        0218 80
    DBCGOTBL       02C0 08
    DBCGPLST       02D0
    DBCGTHAL       02C1 40
    DBCHALBK       02BC
    DBCHALET       0220
    DBCHFRST       0238
    DBCHIRN        027D
    DBCHLAST       023C
    DBCHSID        0292
    DBCIASIT       0200
    DBCINCAC       0218 04
    DBCINIOR       02B0 08
    DBCIORAD       02D0
    DBCIORBK       02BC
    DBCIPARM       02D8
    DBCIPARM32     02DC
    DBCIWAIT       02C0 20
    DBCKEY         0250
    DBCLBA         02E8
    DBCLCKAD       0248
    DBCLOWRN       027B
    DBCLPM         02B2
    DBCMALET       02A4
    DBCMAXCH       024C
    DBCMAXSZ       02CE
    DBCMIXED       02CD 10
    DBCMONO        02C0 80
    DBCMSGID       02C4
    DBCMULTI       02C0 40
    DBCMXENT       0270
    DBCNEXT        029C
    DBCNOCAR       0218 20
    DBCNOREL       021B 40
    DBCNOTEL       0219 80
    DBCNSTD        0218 40
    DBCNXTBB       02C0
    DBCNXTCC       02C2
    DBCNXTHH       02C4
    DBCNXTSV       02C0
    DBCOFFCP       02E0
    DBCOFSET       0294
    DBCOPPTR       0240
    DBCORICC       02C8
    DBCORIEN       02C8
    DBCORIHH       02CA
    DBCORIR        02CC
    DBCPARML       02D4
    DBCPLADR       02CC
    DBCPLCNT       02FC
    DBCPLSIZ       02FE
    DBCPRIM        0218 01
    DBCPROG        02B8
    DBCQDSK        02B0 02
    DBCRC          028C
    DBCRC00        02C2 00
    DBCRC08        02C2 08
    DBCRC12        02C2 0C
    DBCRC255       02C2 FF
    DBCRC40        02C2 28
    DBCRC44        02C2 2C
    DBCRC48        02C2 30
    DBCRDCPY       021B 20
    DBCRDSAV       0280
    DBCRELRT       02A0
    DBCREMOV       02CD 08
    DBCREPLP       0219 20
    DBCREPS        02B0 20
    DBCRTRAK       0268
    DBCSAV         021C
    DBCSAWWR       021B 08
    DBCSBIOP       02C4
    DBCSEKPT       02E0
    DBCSEXIT       02C0 04
    DBCSILI        02CD 20
    DBCSINGL       02B0
    DBCSPECL       02B0
    DBCSSHCT       02C2
    DBCSTD         02CD 04
    DBCSVCCW       02B0
    DBCSWTCH       0218
    DBCSWTC2       0219
    DBCSWTC4       021B
    DBCSWTC5       02A8
    DBCSYNC        02C0 10
    DBCTCHBK       026C
    DBCTCMSK       02D4 00FFFF7C
    DBCTFRST       0244
    DBCTKDAT       0278
    DBCTKHED       02E8
    DBCTKLEN       027E 00000002
    DBCTKPTR       0264
    DBCTKSIZ       027E
    DBCTMPH        02AA
    DBCTRGCL       02C8
    DBCVCYL        0278
    DBCVDEV        02B0 80
    DBCWFAIL       021B 04
    DBCWKLEN       02B0 00000060
    DBCWORK        0208
    DBCWORK1       0208
    DBCWORK2       020C
    DBCWORK3       0210
    DBCWORK4       0214
    DBCWRITE       0218 10
    DBCXSTOR       021B 02
    DBC18RC        02EC
    DBC18SWT       02CD
    DBC250RC       02C2
    DBC64BIT       02C0 04

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:32:13 EDT.
Copyright IBM Corporation, 1990, 2008