CHPBK | Back to Index page

| Prolog Control Block Contents CHPBK 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.

CHPBK Prolog | Top of page

     NAME       : HCPCHPBK
     DESCRIPTION: SPXTAPE Channel Program Block
     DSECT      : CHPBK
     FUNCTION   : Work area to hold a channel program and
                  the resources needed (including an
                  IORBK) to issue an SPXTAPE tape I/O
                  request and handle the completion or
                  recovery procedures.
     LOCATED BY :
                  Routines:
                  HCPSPYWT - to set up the I/O operation
                  HCPSPYWI - interrupt processing
                  HCPSPZRT - to set up the I/O operation
                  HCPSPZRI - interrupt processing
                  Control block fields:
                  TAPCHPQ  - head of queue in the TAPBK
                  CHPNEXT  - next in circular queue
     CREATED BY : HCPSPYWT - SPXTAPE DUMP commands
                  HCPSPZRT - SPXTAPE LOAD and SCAN commands
     DELETED BY : HCPSPYWT - SPXTAPE DUMP commands
                  HCPSPZRT - SPXTAPE LOAD and SCAN commands
     REFERENCES : HCPCHPBK requires HCPIORBK COPY
     RELOCATION CONSIDERATIONS : None

CHPBK Control Block Content | Top of page

     CHPBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      CHPBK          SPXTAPE Channel Program Block
            Reserve space for the base IORBK
    0000    0 Dbl-Word     8 CHPIORBK (83)  Base IORBK region
            Lock for this IORBK and CHPBK work area
    0298  664 Dbl-Word     8 CHPLOCK (3)    Lock to serialize this block
            Commit and recovery control data.
            Last items in the current block
            used to update commit cursors when
            successfully sent to tape.
    02B0  688 Signed       2 CHPCMCLR (0)   Beginning of area to be cleared
                                            before reuse for trailer
    02B0  688 Address      4 CHPCURTK       Last ticket contained in current
                                            block
    02B4  692 Address      4 CHPCMSSQ       Last SSQBK
    02B8  696 Address      4 CHPCMCUR       Address of next Vpage slot in
                                            last SSQBK
    02BC  700 Signed       4 CHPCURHD       Displacement in header of cur hdr
    02C0  704 Signed       4 CHPCMXAB       Amt of XAB data associated with
                                            last tkt remaining to be written
    02C4  708 Address      4 CHPLSTCW       CCW address of the last piece of
                                            data for files that completed in
                                            the current block. If = 0 then
                                            block contains no complete files
    02C8  712 Signed       4 CHPLLPTR       Last offset in page list +1 used
    02CC  716 Address      4 CHPLSTHD       Hdr addr for last completed file
    02D0  720 Signed       4 CHPLBLKZ       Save last block size at last
                                            complete file/tkt in this block.
            Counters, etc.
    02D4  724 Character   16 CHPTKTS        Queue of files completed in this
                                            channel program. Moved to TAPTKTQ
                                            when I/O completes OK.
                                            Single-threaded double-headed
                                            FIFO queue terminated by zero
    02D4  724 Address      4 CHPTKTSH       Head of CHPTKTS
    02D8  728 Address      4 CHPTKTST       Tail of CHPTKTS
    02DC  732 Signed       4 CHPTKTCT       Corresponding count of files on
                                            CHPTKTS
    02E0  736 Signed       4 *              Reserved
    02E4  740 Signed       4 CHPENTRY       Current entry in the header
    02E8  744 Signed       4 CHPLIMIT       After the last entry in the hdr
    02EC  748 Signed       4 CHPLINDX       Index into CCW list of buffers
    02F0  752 Signed       4 CHPOFFST       Offset into block where data
                                            should be added
    02F4  756 Signed       4 *
    02F8  760 Signed       4 CHPPOOLC       Count of pool pages (data pages)
    02FC  764 Address      4 CHPPLIST (14)  List of pages locked for this blk
              00000038       CHPPLLEN       *-CHPPLIST Length to clear
              0000000E       CHPPLMAX       14 Maximum number of entries
    0334  820 Signed       4 *              End flag for PLIST - zero = end
              00000088       CHPCMCRL       *-CHPCMCLR Length of area to be
                                            cleared before reuse for trailer
            Queue of CHPbks link field
    0338  824 Address      4 CHPNEXT        Next work area in circular queue
            Save area across GOTO I/O request
    033C  828 Signed       4 CHPSAVE (7)    Save R3-R9 across call to IOS.QS
            Channel Program and Header Block copied from TAPBK
    0358  856 Dbl-Word     8 CHPPGM (26)    Modeset + hdr + 3*8 (desc + xab +
                                            data)
    0428 1064 Dbl-Word     8 CHPHEADR (37)  Block header
            Pointers
    0550 1360 Signed       4 CHPIDAWA       IDAW list anchor
    0554 1364 Signed       4 CHPIDWNX       Next available IDAW slot
    0558 1368 Signed       4 CHPBUFHL       Host logical buffer addr anchor
    055C 1372 Signed       4 *              Reserved
              00000004       CHPHLLEN       4 Length of CHPBUFHL entries
            End of CHPBK definition
    0560 1376 Dbl-Word     8 CHPRESVD (10)  Round it off
              00000318       CHPLENBY       *-CHPLOCK Extra space (after
                                            IORBK)
              000005B0       CHPIOBY        *-CHPBK Whole work area size in
                                            bytes
              000000B6       CHPIODW        CHPIOBY/8 Same in double words
              00000002       CHPBKCNT       2 Number of work areas per drive
            Redefinition for the channel program build area
    0358  856 Dbl-Word     8 CHPMSCCW       Modeset, if applicable
    0360  864 Address      4 CHPHDCCW       Read/write header CCW
    0364  868 Address      4 CHPHCCWA       Address of the CHPHEADR
    0368  872 Address      4 CHPCCW1        First general CCW
    036C  876 Address      4 CHPCCW1A       Address section for deblocking
    0370  880 Dbl-Word     8 CHPCCWS (20)   File write CCWs - desc, XAB, data
                                            Or read CCW's - up to 8 pages
              00000015       CHPCCWCT       (*-CHPCCW1)/8 Number of CCWs
                                            (doublewords)
              000000B8       CHPPGMLN       *-CHPPGM Must match size defined
                                            above
            Redefinition for the tape block header section
    0428 1064 Character    4 CHPBLKID       Generally 'XHDR', could be 'TRLR'
    042C 1068 Signed       4 CHPBLKSZ       Size of this block in bytes
    0430 1072 Dbl-Word     8 CHPTIME        Time stamp
            Definition of an individual entry
    0438 1080 Dbl-Word     8 CHPHDENT (0)   Start of the first entry
    0438 1080 Character    8 CHPOWNER       File owner
    0440 1088 Signed       4 CHPFSEQ        File sequence number for drive
    0444 1092 Signed       4 CHPSYSID       System spool file ID when dumped
    0448 1096 Signed       2 CHPSPID        User spool file ID when dumped
    044A 1098 Bitstring    1 CHPHDFLG       Flags describing file section
    044B 1099 Bitstring    1 *
    044C 1100 Signed       4 CHPMAPCT       Count of map pages needed for
                                            file
    0450 1104 Signed       4 CHPPAGNO       Starting relative page number
    0454 1108 Signed       2 CHPPAGCT       Count of data pages in block
    0456 1110 Signed       2 CHPXABSZ       Size of XAB section in block
    0458 1112 Signed       2 CHPTKOFF       Offset to ticket - file
                                            descriptor
    045A 1114 Signed       2 CHPXAOFF       Offset to extended attributes buf
    045C 1116 Signed       2 CHPDPOFF       Offset to data pages
    045E 1118 Signed       2 *

CHPBK Storage Layout | Top of page

    *** CHPBK - SPXTAPE Channel Program Block
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       CHPIORBK                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 298 |                                                       |
    *     =                       CHPLOCK                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    * 2B0 |         CHPCURTK          |         CHPCMSSQ          |
    *     +---------------------------+---------------------------+
    * 2B8 |         CHPCMCUR          |         CHPCURHD          |
    *     +---------------------------+---------------------------+
    * 2C0 |         CHPCMXAB          |         CHPLSTCW          |
    *     +---------------------------+---------------------------+
    * 2C8 |         CHPLLPTR          |         CHPLSTHD          |
    *     +---------------------------+---------------------------+
    * 2D0 |         CHPLBLKZ          |                           |
    *     +---------------------------+                           |
    *     |                       CHPTKTS                         |
    *     |                           +---------------------------+
    *     |                           | 2E4
    *     +---------------------------+
    *
    *** CHPBK - SPXTAPE Channel Program Block

    *** Overlay for CHPTKTS in CHPBK
    *
    *                                 +---------------------------+
    * 2D0 ...                     2D4 |         CHPTKTSH          |
    *     +---------------------------+---------------------------+
    * 2D8 |         CHPTKTST          |         CHPTKTCT          |
    *     +---------------------------+---------------------------+
    * 2E0 |///////////////////////////|         CHPENTRY          |
    *     +---------------------------+---------------------------+
    * 2E8 |         CHPLIMIT          |         CHPLINDX          |
    *     +---------------------------+---------------------------+
    * 2F0 |         CHPOFFST          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 2F8 |         CHPPOOLC          |                           |
    *     +---------------------------+                           |
    * 300 |                                                       |
    *     =                       CHPPLIST                        =
    *     |                           +---------------------------+
    * 330 |                           |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 338 |         CHPNEXT           |                           |
    *     +---------------------------+                           |
    * 340 |                                                       |
    *     =                       CHPSAVE                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 358 |                                                       |
    *     =                        CHPPGM                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 428 |                                                       |
    *     =                       CHPHEADR                        =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    * 550 |         CHPIDAWA          |         CHPIDWNX          |
    *     +---------------------------+---------------------------+
    * 558 |         CHPBUFHL          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 560 |                                                       |
    *     =                       CHPRESVD                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 5B0
    *
    *** Overlay for CHPTKTS in CHPBK

    *** Overlay for CHPPGM in CHPBK
    *
    *     +-------------------------------------------------------+
    * 358 |                       CHPMSCCW                        |
    *     +---------------------------+---------------------------+
    * 360 |         CHPHDCCW          |         CHPHCCWA          |
    *     +---------------------------+---------------------------+
    * 368 |         CHPCCW1           |         CHPCCW1A          |
    *     +---------------------------+---------------------------+
    * 370 |                                                       |
    *     =                       CHPCCWS                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 410
    *
    *** Overlay for CHPPGM in CHPBK

    *** Overlay for CHPHEADR in CHPBK
    *
    *     +---------------------------+---------------------------+
    * 428 |         CHPBLKID          |         CHPBLKSZ          |
    *     +---------------------------+---------------------------+
    * 430 |                       CHPTIME                         |
    *     +-------------------------------------------------------+
    * 438 |                       CHPOWNER                        |
    *     +---------------------------+---------------------------+
    * 440 |         CHPFSEQ           |         CHPSYSID          |
    *     +-------------+------+------+---------------------------+
    * 448 |  CHPSPID    |:HDFLG|//////|         CHPMAPCT          |
    *     +-------------+------+------+-------------+-------------+
    * 450 |         CHPPAGNO          |  CHPPAGCT   |  CHPXABSZ   |
    *     +-------------+-------------+-------------+-------------+
    * 458 |  CHPTKOFF   |  CHPXAOFF   |  CHPDPOFF   |/////////////|
    *     +-------------+-------------+-------------+-------------+
    * 460
    *
    *** Overlay for CHPHEADR in CHPBK

CHPBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    CHPBKCNT       0560 00000002
    CHPBLKID       0428
    CHPBLKSZ       042C
    CHPBUFHL       0558
    CHPCCWCT       0370 00000015
    CHPCCWS        0370
    CHPCCW1        0368
    CHPCCW1A       036C
    CHPCMCLR       02B0
    CHPCMCRL       0334 00000088
    CHPCMCUR       02B8
    CHPCMSSQ       02B4
    CHPCMXAB       02C0
    CHPCURHD       02BC
    CHPCURTK       02B0
    CHPDPOFF       045C
    CHPENTRY       02E4
    CHPFSEQ        0440
    CHPHCCWA       0364
    CHPHDCCW       0360
    CHPHDENT       0438
    CHPHDFLG       044A
    CHPHEADR       0428
    CHPHLLEN       055C 00000004
    CHPIDAWA       0550
    CHPIDWNX       0554
    CHPIOBY        0560 000005B0
    CHPIODW        0560 000000B6
    CHPIORBK       0000
    CHPLBLKZ       02D0
    CHPLENBY       0560 00000318
    CHPLIMIT       02E8
    CHPLINDX       02EC
    CHPLLPTR       02C8
    CHPLOCK        0298
    CHPLSTCW       02C4
    CHPLSTHD       02CC
    CHPMAPCT       044C
    CHPMSCCW       0358
    CHPNEXT        0338
    CHPOFFST       02F0
    CHPOWNER       0438
    CHPPAGCT       0454
    CHPPAGNO       0450
    CHPPGM         0358
    CHPPGMLN       0370 000000B8
    CHPPLIST       02FC
    CHPPLLEN       02FC 00000038
    CHPPLMAX       02FC 0000000E
    CHPPOOLC       02F8
    CHPRESVD       0560
    CHPSAVE        033C
    CHPSPID        0448
    CHPSYSID       0444
    CHPTIME        0430
    CHPTKOFF       0458
    CHPTKTCT       02DC
    CHPTKTS        02D4
    CHPTKTSH       02D4
    CHPTKTST       02D8
    CHPXABSZ       0456
    CHPXAOFF       045A

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:27:19 EDT.
Copyright IBM Corporation, 1990, 2020