$MSTBK | Back to Index page

| Prolog Control Block Contents $MSTBK 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.

$MSTBK Prolog | Top of page

     NAME       : LGRMSTBK
     DESCRIPTION: Relocation mapping for HCPMSTBK
     DSECT      : $MSTBK
     FUNCTION   : LGRMSTBK describes those fields of the MSTBK that
                  will be migrated to the destination system during
                  guest relocation.
     LOCATED BY : This is a mapping of the RDODATA area within the
                  RDOBK during guest relocation.
     RELOCATION CONSIDERATIONS : This control block is used during live guest
                  relocation.  It is used to relocate a control block
                  defined in a corresponding HCP COPY file.  Any
                  fields or bits defined in HCPMSTBK which are
                  required on the destination system must be defined
                  here, and code must be added to migrate the field
                  or bit during a relocation.

$MSTBK Control Block Content | Top of page

     $MSTBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      $MSTBK         Relocation mapping for HCPMSTBK
              00000001       $MST_VER       1 Mapping version number
    0000    0 Signed       2 $MST_HDRL      Header length (in bytes)
    0002    2 Signed       2 $MST_BITL      Length of mapped bits (in bytes)
    0004    4 Signed       4 *              Reserved for future use
              00000008       $MST_HDLN      *-$MSTBK Length of header (bytes)
          NOTES      : This mapping is not intended to be comprehensive,
                since for the most part the MSTBKs that will be
                relocated contain simple character strings. The
                decoding routine(s) on the destination system will
                be aware of the context for the incoming MSTBK, and
                will therefore be able to set flags and other data
                as required.
          Bit map: Contains the MSTBK flags that are subject to
                   relocation. These bits are defined sequentially,
                   regardless of how they are defined in HCPMSTBK.
                   This yields a consistent mapping that ensures
                   compatibility when a guest is relocated between
                   systems at differing service levels.
                   Names in the comments column indicate the control
                   block byte which contains the flag. This name is
                   subject to change if the flag definition changes.
             ====> NEVER change bits which already exist here.
             ====> NEVER change the order of bits in this section.
             ====> ALWAYS add new bits at the end of this section,
                   together with new flag bytes as required.
    0008    8 Signed       2 $MST_BITS (0)  Bit map area
              00000000       $MST_BLEN      *-$MST_BITS Length of bit map
                                            area
          Data:    Contains all HCPMSTBK data that is subject to
                   relocation, except for flag bits, which are
                   handled separately.
                   All fields are defined as XLnn to avoid alignment
                   warnings and to pack the data efficiently.
             ====> NEVER change fields which already exist here.
             ====> NEVER change the order of fields in this section.
             ====> ALWAYS add new fields at the end of this section.
                   together with new flag bytes as required.
    0008    8 Bitstring    1 $MST_DATA (0)  Start of data map
    0008    8 Bitstring    4 $MSTPTR        -> RDO offset to next $MSTBK
    000C   12 Bitstring    4 $MSTTLEN       Message length
    0010   16 Bitstring    6 $MSTCFRPM      HCPCFRWT parameters
    0016   22 Bitstring    4 $MSTTEXT       -> RDO offset to message text
                                            block
              0000001A       $MST_LEN       *-$MSTBK Fixed length, in bytes
              00000004       $MST_SZ        ($MST_LEN+7)/8 Size in
                                            doublewords

$MSTBK Storage Layout | Top of page

    *** $MSTBK - Relocation mapping for HCPMSTBK
    *
    *     +-------------+-------------+---------------------------+
    *   0 | $MST_HDRL   | $MST_BITL   |///////////////////////////|
    *     +-------------+-------------+---------------------------+
    *   8 |         $MSTPTR           |         $MSTTLEN          |
    *     +---------------------------+-------------+-------------+
    *  10 |               $MSTCFRPM                 | $MSTTEXT-   |
    *     +-------------+---------------------------+-------------+
    *  18 |   -(016)    | 1A
    *     +-------------+
    *
    *** $MSTBK - Relocation mapping for HCPMSTBK

$MSTBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    $MST_BITL      0002
    $MST_BITS      0008
    $MST_BLEN      0008 00000000
    $MST_DATA      0008
    $MST_HDLN      0004 00000008
    $MST_HDRL      0000
    $MST_LEN       0016 0000001A
    $MST_SZ        0016 00000004
    $MST_VER       0000 00000001
    $MSTCFRPM      0010
    $MSTPTR        0008
    $MSTTEXT       0016
    $MSTTLEN       000C

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:32:09 EDT.
Copyright IBM Corporation, 1990, 2020