PAGBK - 64-bit CP - V4R4.0

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.

#### 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 (57)  This area reserved for the IORBK.
    01C8  456 Dbl-Word     8 PAGEXPBK (23)  This area reserved for the EXPBK.
         The area below is used for the Set Paging CCW data.
    0280  640 Bitstring   16 PAGSPPAR (0)   This area contains the cache CCW
                                            data information.
    0280  640 Bitstring   10 PAGDATA (0)    This is the data area for the Set
                                            Paging Parameter CCW.
    0280  640 Bitstring    1 *
    0281  641 Bitstring    9 PAGDATA1 (0)   Defined for the clear move
                                            instruction.
    0281  641 Bitstring    5 *
    0286  646 Bitstring    4 PAGCCHH        The cylinder/head info.
    028A  650 Bitstring    6 *              Reserved for IBM use
         Redefinition of set paging parameter data area for ECKD and FBA paging
         devices.
    0280  640 Bitstring   16 PAGDXDA        Define extent data area mapped by
                                            DXDA (ECKD) or DFDA (FBA)
              00000290       PAGCKSIZ       *-PAGBK Actual block size in
                                            bytes
              00000052       PAGSIZE        (((*-PAGBK)+7)/8) PAGBK siz in
                                            DWs (leave room for expansion)
              00000290       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                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 1C8 |                                                       |
    *     =                       PAGEXPBK                        =
    *     |                                                       |
    *     +------+----------------------------------+-------------+
    * 280 |//////|//////////////////////////////////|  PAGCCHH-   |
    *     +------+------+---------------------------+-------------+
    * 288 |   -(286)    |/////////////////////////////////////////|
    *     +-------------+-----------------------------------------+
    * 290
    *
    *** PAGBK - Page I/O DSECT Block

    *** Overlay for PAGSPPAR in PAGBK
    *
    *     +-------------------------------------------------------+
    * 280 |                       PAGDXDA                         |
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 290
    *
    *** Overlay for PAGSPPAR in PAGBK

#### PAGBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    PAGBSIZE       0280 00000290
    PAGCCHH        0286
    PAGCKSIZ       0280 00000290
    PAGDATA        0280
    PAGDATA1       0281
    PAGDXDA        0280
    PAGEXPBK       01C8
    PAGIORBK       0000
    PAGSIZE        0280 00000052
    PAGSPPAR       0280

This information is based on z/VM V4R4.0. Last updated on 30 Jul 2003 at 13:01:48 EDT.
Copyright IBM Corporation, 1990, 2003