DSIBK | Back to Index page

| Prolog Control Block Contents DSIBK 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.

DSIBK Prolog | Top of page

     NAME       : HCPDSIBK
     DESCRIPTION: Dump Space Information Area
     DSECT      : DSIBK
     FUNCTION   : The DSIBK resides in host permanent storage and is
                  used to contain the dump space allocation CALBK,
                  size information and the channel program construction
                  area for CP system abend dump processing
     LOCATED BY : SYSDSIBK IN HCPSYSCM
     CREATED BY : SYSTEM DEFINITION
     DELETED BY : NOT DELETED
     SERIALIZED : The Dump Space Allocation Lock contained
                  within this data area.
     RELOCATION CONSIDERATIONS : None
     COMMENTS   : DSIDmpLo and DSIDmpHi are threshold values used
                  to communicate to the storage management.  If
                  RSADmpCP is larger than DSIDmpHi then it is
                  time to get more dump space.  If RSADmpCP is
                  smaller than DSIDmpLo then it is time to
                  release and reallocate the dump space.

DSIBK Control Block Content | Top of page

     DSIBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      DSIBK          Dump Space Information Area
    0000    0 Dbl-Word     8 DSILOCK (3)    Dump Space Allocation Lock
          The following fields are for additional cluster allocation, when
           needed.
    0018   24 Signed       4 DSIOLDHI       Previous Hi Threshold.
    001C   28 Signed       4 DSITAPGS       Total DASD pages currently
                                            allocated
    0020   32 Signed       4 DSIDmpHi       High Threshold value for CP-owned
                                            pages. When the value in this
                                            field is X'FFFFFFFF' no
                                            additional DASD dump space is to
                                            be obtained.
    0024   36 Signed       4 DSIRSASV       RSADmpCP at time of reallocation
    0028   40 Signed       4 DSIDmpLo       Low Threshold value for CP-owned
                                            pages. When the value in this
                                            field is X'FFFFFFFF', extra DASD
                                            dump is not released
    002C   44 Signed       4 * (0)
    002C   44 Bitstring    1 DSIFLAG        Test and set flag which indicates
                                            that a call to allocate
                                            additional DASD dump space has
                                            been stacked.
    002D   45 Bitstring    3 *              RESERVED FOR FUTURE IBM USE
          Multi-page write buffer start and end addresses.
    0030   48 Address      4 DSIMPWBF       Start address of buffer.
    0034   52 Address      4 DSIMPWBE       End address of buffer. Is
                                            actually address of byte after
                                            end of buffer. DSIMPWBE-DSIMPWBF
                                            = buffer length.
    0038   56 Dbl-Word     8 * (0)          Force boundary alignment (if
                                            needed)
    0038   56 Bitstring   56 DSICALBK       CALBK header section
             This area contains the CALBK for the dump space allocation
             function. It is required when managing clusters of DASD dump
             space and is needed as input to HCPPGCAL and HCPPGCRL, the
             cluster allocation and release entry points, respectively.
          The number of entries in the cluster allocation table is
          based on experience.  As the size of the average dump
          increases in subsequent releases, customers may encounter
          message HCP9255I more frequently and the value for
          DSIENTCT may need to be increased.
          HCPDMP's work area for channel program construction
          will be one full page plus whatever remains of the page
          at the end of the cluster allocation table.
              00000FA0       DSIENTCT       4000 Number of entries in CALBK
    0070  112 Dbl-Word     8 DSIENTRY (4000)
                                            Space for Cluster Allocation
                                            Table
              00007D00       DSIENTSZ       *-DSIENTRY SIZE OF CLUSTER
                                            ALLOCATION TABLE
    7D70 2112 Dbl-Word     8 * (0)          Force boundary alignment for
                                            CCW's
    7D70 2112 Unknown      8 DSICHPGM (594) Space for hard abend dump channel
                                            program construction (used by
                                            HCPDMP)
              00001290       DSICHPSZ       *-DSICHPGM SIZE OF CHANNEL
                                            PROGRAM AREA
              00001200       DSISIZE        (*-DSIBK+7)/8 DSIBK ENTRY SIZE IN
                                            DOUBLEWORDS
              00009000       DSIBSIZE       DSISIZE*8 DSIBK ENTRY SIZE IN
                                            BYTES
          OVERLAY FOR ACCESSING THE NEXT ASA FOR Space INFORMATION
    0070  112 Signed       4 DSIASA (0)     ASA for start of allocation
    0070  112 Bitstring    2 DSICC          If CKD or ECKD, cylinder part
    0072  114 Bitstring    1 DSIP           If CKD or ECKD, page part
    0073  115 Bitstring    1 DSIV           volume part of DSIASA
    0074  116 Signed       4 DSINPGS        NUMBER OF Pages ALLOCATED
    0078  120 Signed       4 DSINEXT (0)    Start of the next ASA entry
    7D70 2112 Dbl-Word     8 DSICCW         CCW construction area
    7D78 2120 Dbl-Word     8 DSICCWNX (0)   Start of next CCW

DSIBK Storage Layout | Top of page

    *** DSIBK - Dump Space Information Area
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       DSILOCK                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    *  18 |         DSIOLDHI          |         DSITAPGS          |
    *     +---------------------------+---------------------------+
    *  20 |         DSIDMPHI          |         DSIRSASV          |
    *     +---------------------------+------+--------------------+
    *  28 |         DSIDMPLO          |:FLAG |////////////////////|
    *     +---------------------------+------+--------------------+
    *  30 |         DSIMPWBF          |         DSIMPWBE          |
    *     +---------------------------+---------------------------+
    *  38 |                                                       |
    *     =                       DSICALBK                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  70 |                                                       |
    *     =                       DSIENTRY                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *7D70 |                                                       |
    *     =                       DSICHPGM                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *9000
    *
    *** DSIBK - Dump Space Information Area

    *** Overlay for DSIENTRY in DSIBK
    *
    *     +-------------+------+------+---------------------------+
    *  70 |   DSICC     |DSIP  |DSIV  |         DSINPGS           |
    *     +-------------+------+------+---------------------------+
    *
    *** Overlay for DSIENTRY in DSIBK

    *** Overlay for DSICHPGM in DSIBK
    *
    *     +-------------------------------------------------------+
    *7D70 |                        DSICCW                         |
    *     +-------------------------------------------------------+
    *
    *** Overlay for DSICHPGM in DSIBK

DSIBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    DSIASA         0070
    DSIBSIZE       7D70 00009000
    DSICALBK       0038
    DSICC          0070
    DSICCW         7D70
    DSICCWNX       7D78
    DSICHPGM       7D70
    DSICHPSZ       7D70 00001290
    DSIDmpHi       0020
    DSIDmpLo       0028
    DSIENTCT       0038 00000FA0
    DSIENTRY       0070
    DSIENTSZ       0070 00007D00
    DSIFLAG        002C
    DSILOCK        0000
    DSIMPWBE       0034
    DSIMPWBF       0030
    DSINEXT        0078
    DSINPGS        0074
    DSIOLDHI       0018
    DSIP           0072
    DSIRSASV       0024
    DSISIZE        7D70 00001200
    DSITAPGS       001C
    DSIV           0073

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:27:53 EDT.
Copyright IBM Corporation, 1990, 2020