PAGBK | Back to Index page

| Prolog Control Block Contents PAGBK 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.

PAGBK Prolog | Top of page

     NAME       : HCPPAGBK
     DESCRIPTION: Page I/O DSECT Block
     DSECT      : PAGBK
     FUNCTION   : PAGBK maps a free storage block that contains
                  the IORBK, EXPBK (for single exposures), and
                  the Set Paging Parameter CCW or the Define
                  Extent Data Area.
     LOCATED BY : EXPIORBK - Field in the exposure block that points
                  to the beginning of the block.
     RELOCATION CONSIDERATIONS : None
     NOTES      : To use this dsect the following dsects must also
                  be included in the module. HCPIORBK, HCPEXPBK.
                  This block contains an IORBK and CCW data.  It must
                  be backed below 2-Gig.  (Defaulted in CBITABLE).

PAGBK Control Block Content | Top of page

     PAGBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      PAGBK          Page I/O DSECT Block
                 Beginning of the IORBK for this exposure.
    0000    0 Dbl-Word     8 PAGIORBK (83)  This area reserved for the IORBK.
    0298  664 Dbl-Word     8 PAGEXPBK (54)  This area reserved for the EXPBK.
                 The area below is used for the Set Paging CCW data.
    0448 1096 Bitstring   32 PAGSPPAR (0)   This area contains the cache CCW
                                            data information.
    0448 1096 Bitstring   10 PAGDATA (0)    This is the data area for the Set
                                            Paging Parameter CCW.
    0448 1096 Bitstring    1 *
    0449 1097 Bitstring    9 PAGDATA1 (0)   Defined for the clear move
                                            instruction.
    0449 1097 Bitstring    5 *
    044E 1102 Bitstring    4 PAGCCHH        The cylinder/head info.
    0452 1106 Bitstring   22 *              Reserved for IBM use
                 Redefinition of set paging parameter data area
                 for ECKD and FBA paging devices.
    0448 1096 Bitstring   32 PAGDXDA        Define extent data area mapped by
                                            DXDA (ECKD) or DFDA (FBA)
              00000468       PAGCKSIZ       *-PAGBK Actual block size in
                                            bytes
              0000008D       PAGSIZE        (((*-PAGBK)+7)/8) PAGBK siz in
                                            DWs (leave room for expansion)
              00000468       PAGBSIZE       *-PAGBK Non theoretical PAGBK
                                            size in bytes (leave room for
                                            expansion)

PAGBK Storage Layout | Top of page

    *** PAGBK - Page I/O DSECT Block
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       PAGIORBK                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 298 |                                                       |
    *     =                       PAGEXPBK                        =
    *     |                                                       |
    *     +------+----------------------------------+-------------+
    * 448 |//////|//////////////////////////////////|  PAGCCHH-   |
    *     +------+------+---------------------------+-------------+
    * 450 |   -(44E)    |/////////////////////////////////////////|
    *     +-------------+/////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 468
    *
    *** PAGBK - Page I/O DSECT Block

    *** Overlay for PAGSPPAR in PAGBK
    *
    *     +-------------------------------------------------------+
    * 448 |                                                       |
    *     =                       PAGDXDA                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 468
    *
    *** Overlay for PAGSPPAR in PAGBK

PAGBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    PAGBSIZE       0448 00000468
    PAGCCHH        044E
    PAGCKSIZ       0448 00000468
    PAGDATA        0448
    PAGDATA1       0449
    PAGDXDA        0448
    PAGEXPBK       0298
    PAGIORBK       0000
    PAGSIZE        0448 0000008D
    PAGSPPAR       0448

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:29:30 EDT.
Copyright IBM Corporation, 1990, 2020