$MSGBK | Back to Index page

| Prolog Control Block Contents $MSGBK 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.

$MSGBK Prolog | Top of page

     NAME       : LGRMSGBK
     DESCRIPTION: Relocation mapping for HCPMSGBK
     DSECT      : $MSGBK
     FUNCTION   : LGRMSGBK describes those fields of the MSGBK 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 HCPMSGBK 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.

$MSGBK Control Block Content | Top of page

     $MSGBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      $MSGBK         Relocation mapping for HCPMSGBK
              00000001       $MSG_VER       1 Mapping version number
    0000    0 Signed       2 $MSG_HDRL      Header length (in bytes)
    0002    2 Signed       2 $MSG_BITL      Length of mapped bits (in bytes)
    0004    4 Signed       4 *              Reserved for future use
              00000008       $MSG_HDLN      *-$MSGBK Length of header (bytes)
          Bit map: Contains the MSGBK flags that are subject to
                   relocation. These bits are defined sequentially,
                   regardless of how they are defined in HCPMSGBK.
                   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 $MSG_BITS (0)  Bit map area
              00000000       $MSG_BLEN      *-$MSG_BITS Length of bit map
                                            area
          Data:    Contains all HCPMSGBK 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 $MSG_DATA (0)  Start of data map
    0008    8 Bitstring    4 $MSGFPNT       -> RDO offset to next $MSGBK
    000C   12 Bitstring    4 $MSGTGCLS      TARGET MESSAGE CLASS
    0010   16 Bitstring    4 $MSGSNDAD      -> RDO offset to message data
    0014   20 Bitstring    4 $MSGSNDLN      SEND BUFFER LENGTH
              00000018       $MSG_LEN       *-$MSGBK Total length, in bytes
              00000003       $MSG_SZ        ($MSG_LEN+7)/8 Size in
                                            doublewords

$MSGBK Storage Layout | Top of page

    *** $MSGBK - Relocation mapping for HCPMSGBK
    *
    *     +-------------+-------------+---------------------------+
    *   0 | $MSG_HDRL   | $MSG_BITL   |///////////////////////////|
    *     +-------------+-------------+---------------------------+
    *   8 |         $MSGFPNT          |        $MSGTGCLS          |
    *     +---------------------------+---------------------------+
    *  10 |        $MSGSNDAD          |        $MSGSNDLN          |
    *     +---------------------------+---------------------------+
    *  18
    *
    *** $MSGBK - Relocation mapping for HCPMSGBK

$MSGBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    $MSG_BITL      0002
    $MSG_BITS      0008
    $MSG_BLEN      0008 00000000
    $MSG_DATA      0008
    $MSG_HDLN      0004 00000008
    $MSG_HDRL      0000
    $MSG_LEN       0014 00000018
    $MSG_SZ        0014 00000003
    $MSG_VER       0000 00000001
    $MSGFPNT       0008
    $MSGSNDAD      0010
    $MSGSNDLN      0014
    $MSGTGCLS      000C

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:32:08 EDT.
Copyright IBM Corporation, 1990, 2020