TPCBK | Back to Index page

| Prolog Control Block Contents TPCBK 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.

TPCBK Prolog | Top of page

     NAME       : HCPTPCBK
     DESCRIPTION: TAPE PATHING CONTROL BLOCK
     DSECT      : TPCBK
     FUNCTION   : CONTAINS TAPE PATHING INFORMATION
     LOCATED BY : VDEVDYPT IN VIRTUAL DEVICE BLOCK
     CREATED BY : HCPVDSAT (DURING ATTACH OR DEDICATE PROC)
     DELETED BY : HCPDTDEV (DURING DETACH COMMAND PROCESSING)
     SERIALIZED : BEING ACCESSED FOR A UNIQUE TASK
     RELOCATION CONSIDERATIONS : This control block is relocated as part of a live
                  guest relocation (LGR).  The bits and fields that
                  need to be relocated are defined in the
                  corresponding LGRTPCBK COPY file.  Whenever changes
                  are made to this control block, consideration must
                  be given to any effects these changes will have on
                  a relocation.  If any new fields or bits are
                  defined, they may need to be relocated.  If
                  existing bits or fields are changed, corresponding
                  modifications may be required in the LGR version of
                  this control block.  Consider also the effects of
                  these changes on a relocation involving a back-level
                  release of CP.

TPCBK Control Block Content | Top of page

     TPCBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      TPCBK          TAPE PATHING CONTROL BLOCK
    0000    0 Bitstring   12 TPCBLOCK (8)   EIGHT ENTRIES OF PATHING
                                            INFORMATION
              0000000C       TPCSIZE        (*-TPCBK+7)/8 TPCBK SIZE IN
                                            DOUBLE WORDS
    0000    0 Bitstring   12 TPCENTRY (0)   ONE ENTRY OF TAPE PATHING BLOCK
    0000    0 Bitstring   11 TPCGROUP       TAPE PATH GROUP ID
    000B   11 Bitstring    1 TPCFLAGS       TAPE PATHING FLAGS
              1... ....      TPCFGRP        X'80' TPCFGRP PATH IS GROUPED
              0000000C       TPCNXTEN       *-TPCENTRY

TPCBK Storage Layout | Top of page

    *** TPCBK - TAPE PATHING CONTROL BLOCK
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       TPCBLOCK                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  60
    *
    *** TPCBK - TAPE PATHING CONTROL BLOCK

    *** Overlay for TPCBLOCK in TPCBK
    *
    *     +-------------------------------------------------------+
    *   0 |                       TPCGROUP                        |
    *     |                    +------+---------------------------+
    *   8 |                    |:FLAGS| C
    *     +--------------------+------+
    *
    *** Overlay for TPCBLOCK in TPCBK

TPCBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    TPCBLOCK       0000
    TPCENTRY       0000
    TPCFGRP        000B 80
    TPCFLAGS       000B
    TPCGROUP       0000
    TPCNXTEN       000B 0000000C
    TPCSIZE        0000 0000000C

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:31:18 EDT.
Copyright IBM Corporation, 1990, 2020