FORBK | Back to Index page

| Prolog Control Block Contents FORBK DSECT FORCTBL 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.

FORBK Prolog | Top of page

     NAME       : HCPFORBK
     DESCRIPTION: The FOR control block.
     DSECT      : FORBK
     FUNCTION   : Provides a mapping of the FORBK control block containing
                  the *ASYNCMD connection table for a virtual configuration.
     LOCATED BY : The VMDFORBK field in the base VMDBK points to the FORBK
     CREATED BY : Entry point HCPASYCN will create the FORBK on the first connection
                  to the *ASYNCMD system service.
     DELETED BY : The following entry points:
                  HCPFORSP - End of FOR command handler
                  HCPFORRT - Reset handler
     REFERENCES : FORCTBL - mapping of a single *ASYNCMD connection table entry
     SERIALIZED : When accessing the FORBK, the lock hierarchy is
                  as follows: first obtain the IUCV lock, then
                  get the FORBK lock.
     RELOCATION CONSIDERATIONS : None
     COMPATIBILITY AND MIGRATION CONCERNS : None

FORBK Control Block Content | Top of page

     FORBK DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      FORBK          The FOR control block.
    0000    0 Dbl-Word     8 FORLOCK (3)    FORBK Lock
    0018   24 Bitstring    1 FORFLAG        Flag byte
              1... ....      FORORPHN       X'80' FORORPHN This FORBK is
                                            orphaned
              .1.. ....      FORALLSP       X'40' FORALLSP All slots in use
                                            are sever-pending
    0019   25 Bitstring    1 *              Reserved for future IBM use
    001A   26 Signed       2 FORNXFRE       The number of the next available
                                            slot in the *ASYNCMD connection
                                            table. Slots are numbered 0-7, if
                                            FORNXFRE is 8, then the table is
                                            full.
    001C   28 Signed       2 FORMRCON       The number of the most recently
                                            connected slot
    001E   30 Signed       2 *              Reserved for future IBM use
    0020   32 Bitstring    8 FORTBL (2)     *ASYNCMD connection table
              00000060       FORSIZEB       *-FORBK Size of FORBK in bytes
              0000000C       FORSIZE        (FORSIZEB+7)/8 Size of FORBK in
                                            double words
          FORCTBL - mapping of a single *ASYNCMD connection table entry
              00000008       FORECNT        8 Number of entries in the
                                            *ASYNCMD connection table

     FORCTBL DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      FORCTBL        The FOR control block.
    0000    0 Signed       2 FORCUPTH       User-side path ID
    0002    2 Signed       2 FORCAPTH       *ASYNCMD-side path ID
    0004    4 Signed       2 FORCUCTR       Count of outstanding FOR commands
    0006    6 Bitstring    1 FORCFLAG       Flag byte
              1... ....      FORCSEVP       X'80' FORCSEVP Path is
                                            sever-pending
    0007    7 Bitstring    1 *              Reserved for future IBM use
              00000008       FORCSIZB       *-FORCTBL Size in FORCTBL in
                                            bytes
              00000001       FORCSIZE       (FORCSIZB+7)/8 Size in FORCTBL in
                                            double words

FORBK Storage Layout | Top of page

    *** FORBK - The FOR control block.
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       FORLOCK                         =
    *     |                                                       |
    *     +------+------+-------------+-------------+-------------+
    *  18 |:FLAG |//////|  FORNXFRE   |  FORMRCON   |/////////////|
    *     +------+------+-------------+-------------+-------------+
    *  20 |                        FORTBL                         |
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  30
    *
    *** FORBK - The FOR control block.

    *** FORCTBL - The FOR control block.
    *
    *     +-------------+-------------+-------------+------+------+
    *   0 |  FORCUPTH   |  FORCAPTH   |  FORCUCTR   |:CFLAG|//////|
    *     +-------------+-------------+-------------+------+------+
    *   8
    *
    *** FORCTBL - The FOR control block.

FORBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    FORALLSP       0018 40
    FORCAPTH       0002
    FORCFLAG       0006
    FORCSEVP       0006 80
    FORCSIZB       0007 00000008
    FORCSIZE       0007 00000001
    FORCUCTR       0004
    FORCUPTH       0000
    FORECNT        0020 00000008
    FORFLAG        0018
    FORLOCK        0000
    FORMRCON       001C
    FORNXFRE       001A
    FORORPHN       0018 80
    FORSIZE        0020 0000000C
    FORSIZEB       0020 00000060
    FORTBL         0020

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:28:15 EDT.
Copyright IBM Corporation, 1990, 2020