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 (65)  This area reserved for the IORBK.
    0208  520 Dbl-Word     8 PAGEXPBK (25)  This area reserved for the EXPBK.
                 The area below is used for the Set Paging CCW data.
    02D0  720 Bitstring   32 PAGSPPAR (0)   This area contains the cache CCW
                                            data information.
    02D0  720 Bitstring   10 PAGDATA (0)    This is the data area for the Set
                                            Paging Parameter CCW.
    02D0  720 Bitstring    1 *
    02D1  721 Bitstring    9 PAGDATA1 (0)   Defined for the clear move
                                            instruction.
    02D1  721 Bitstring    5 *
    02D6  726 Bitstring    4 PAGCCHH        The cylinder/head info.
    02DA  730 Bitstring   22 *              Reserved for IBM use
                 Redefinition of set paging parameter data area
                 for ECKD and FBA paging devices.
    02D0  720 Bitstring   32 PAGDXDA        Define extent data area mapped by
                                            DXDA (ECKD) or DFDA (FBA)
              000002F0       PAGCKSIZ       *-PAGBK Actual block size in
                                            bytes
              0000005E       PAGSIZE        (((*-PAGBK)+7)/8) PAGBK siz in
                                            DWs (leave room for expansion)
              000002F0       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                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 208 |                                                       |
    *     =                       PAGEXPBK                        =
    *     |                                                       |
    *     +------+----------------------------------+-------------+
    * 2D0 |//////|//////////////////////////////////|  PAGCCHH-   |
    *     +------+------+---------------------------+-------------+
    * 2D8 |   -(2D6)    |/////////////////////////////////////////|
    *     +-------------+/////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 2F0
    *
    *** PAGBK - Page I/O DSECT Block

    *** Overlay for PAGSPPAR in PAGBK
    *
    *     +-------------------------------------------------------+
    * 2D0 |                                                       |
    *     =                       PAGDXDA                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 2F0
    *
    *** Overlay for PAGSPPAR in PAGBK

#### PAGBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    PAGBSIZE       02D0 000002F0
    PAGCCHH        02D6
    PAGCKSIZ       02D0 000002F0
    PAGDATA        02D0
    PAGDATA1       02D1
    PAGDXDA        02D0
    PAGEXPBK       0208
    PAGIORBK       0000
    PAGSIZE        02D0 0000005E
    PAGSPPAR       02D0

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:53:29 EDT.
Copyright IBM Corporation, 1990, 2008