Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### PAGBK

Prolog

Control Block Contents
PAGBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### PAGBK Prolog

     NAME       : HCPPAGBK
     DESCRIPTION: Page I/O DSECT Block
     DSECT      : PAGBK
     FUNCTION   : PAGBK maps a 512 byte aligned 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.
     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
                  backed below 2-Gig.  (Defaulted in CBITABLE).

#### PAGBK Control Block Content

#### PAGBK DSECT

    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 (59)  This area reserved for the IORBK.
    01D8  472 Dbl-Word     8 PAGEXPBK (23)  This area reserved for the EXPBK.
                 The area below is used for the Set Paging CCW data.
    0290  656 Bitstring   16 PAGSPPAR (0)   This area contains the cache CCW
                                            data information.
    0290  656 Bitstring   10 PAGDATA (0)    This is the data area for the Set
                                            Paging Parameter CCW.
    0290  656 Bitstring    1 *
    0291  657 Bitstring    9 PAGDATA1 (0)   Defined for the clear move
                                            instruction.
    0291  657 Bitstring    5 *
    0296  662 Bitstring    4 PAGCCHH        The cylinder/head info.
    029A  666 Bitstring    6 *              Reserved for IBM use
                 Redefinition of set paging parameter data area
                 for ECKD and FBA paging devices.
    0290  656 Bitstring   16 PAGDXDA        Define extent data area mapped by
                                            DXDA (ECKD) or DFDA (FBA)
              000002A0       PAGCKSIZ       *-PAGBK Actual block size in
                                            bytes
              00000054       PAGSIZE        (((*-PAGBK)+7)/8) PAGBK siz in
                                            DWs (leave room for expansion)
              000002A0       PAGBSIZE       *-PAGBK Non theoretical PAGBK
                                            size in bytes (leave room for
                                            expansion)
                 CKMAINT PAGCKSIZ,GT,512    Check block size

#### PAGBK Storage Layout

    *** PAGBK - Page I/O DSECT Block
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       PAGIORBK                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 1D8 |                                                       |
    *     =                       PAGEXPBK                        =
    *     |                                                       |
    *     +------+----------------------------------+-------------+
    * 290 |//////|//////////////////////////////////|  PAGCCHH-   |
    *     +------+------+---------------------------+-------------+
    * 298 |   -(296)    |/////////////////////////////////////////|
    *     +-------------+-----------------------------------------+
    * 2A0
    *
    *** PAGBK - Page I/O DSECT Block

    *** Overlay for PAGSPPAR in PAGBK
    *
    *     +-------------------------------------------------------+
    * 290 |                       PAGDXDA                         |
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 2A0
    *
    *** Overlay for PAGSPPAR in PAGBK

#### PAGBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    PAGBSIZE       0290 000002A0
    PAGCCHH        0296
    PAGCKSIZ       0290 000002A0
    PAGDATA        0290
    PAGDATA1       0291
    PAGDXDA        0290
    PAGEXPBK       01D8
    PAGIORBK       0000
    PAGSIZE        0290 00000054
    PAGSPPAR       0290

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 17:13:55 EDT.
Copyright IBM Corporation, 1990, 2005