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 (64)  This area reserved for the IORBK.
0200  512 Dbl-Word     8 PAGEXPBK (23)  This area reserved for the EXPBK.
             The area below is used for the Set Paging CCW data.
02B8  696 Bitstring   16 PAGSPPAR (0)   This area contains the cache CCW
                                        data information.
02B8  696 Bitstring   10 PAGDATA (0)    This is the data area for the Set
                                        Paging Parameter CCW.
02B8  696 Bitstring    1 *
02B9  697 Bitstring    9 PAGDATA1 (0)   Defined for the clear move
                                        instruction.
02B9  697 Bitstring    5 *
02BE  702 Bitstring    4 PAGCCHH        The cylinder/head info.
02C2  706 Bitstring    6 *              Reserved for IBM use
             Redefinition of set paging parameter data area
             for ECKD and FBA paging devices.
02B8  696 Bitstring   16 PAGDXDA        Define extent data area mapped by
                                        DXDA (ECKD) or DFDA (FBA)
          000002C8       PAGCKSIZ       *-PAGBK Actual block size in
                                        bytes
          00000059       PAGSIZE        (((*-PAGBK)+7)/8) PAGBK siz in
                                        DWs (leave room for expansion)
          000002C8       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                        =
*     |                                                       |
*     +-------------------------------------------------------+
* 200 |                                                       |
*     =                       PAGEXPBK                        =
*     |                                                       |
*     +------+----------------------------------+-------------+
* 2B8 |//////|//////////////////////////////////|  PAGCCHH-   |
*     +------+------+---------------------------+-------------+
* 2C0 |   -(2BE)    |/////////////////////////////////////////|
*     +-------------+-----------------------------------------+
* 2C8
*
*** PAGBK - Page I/O DSECT Block
          
*** Overlay for PAGSPPAR in PAGBK
*
*     +-------------------------------------------------------+
* 2B8 |                       PAGDXDA                         |
*     |                                                       |
*     +-------------------------------------------------------+
* 2C8
*
*** Overlay for PAGSPPAR in PAGBK

PAGBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
PAGBSIZE       02B8 000002C8
PAGCCHH        02BE
PAGCKSIZ       02B8 000002C8
PAGDATA        02B8
PAGDATA1       02B9
PAGDXDA        02B8
PAGEXPBK       0200
PAGIORBK       0000
PAGSIZE        02B8 00000059
PAGSPPAR       02B8