DX1BK Back to Index page
 
Prolog 
Control Block Contents 
   DX1BK 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.


  DX1BK Prolog Top of page
  
 NAME       : HCPDX1BK
 DESCRIPTION: Minidisk extent index level 1.
 DSECT      : DX1BK
 FUNCTION   : A DX1BK entry points to a DX2BK which can contain
              up to 128 minidisk extents.
 LOCATED BY : MPEDX1BK  - HCPMPEBK pointer to DX1BK.
 CREATED BY : HCPMSMIP  When a Diagnose 244 is issued by the user.
 DELETED BY : HCPAMD44  During an identify pool function the
              previous DX1BK will be deleted if any.
              HCPMSMDP  During storage reset operation.
 RELOCATION CONSIDERATIONS : None
 COMMENTS   :
 
 
  DX1BK Control Block Content Top of page
  




 DX1BK DSECT
Top of page


Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      DX1BK          Minidisk extent index level 1.
0000    0 Signed       4 DX1HPRBN       Highest PRBN contained in the
                                        second level page.
          00000004       DX1LENET       *-DX1HPRBN Length of this entry.
0004    4 Signed       4 DX1NXTET (511) Next entry in this block.
0800 2048 Bitstring    4 DX1DX2XT (0)   Description of the second level
                                        structure (DX2BK location packed
                                        with the extent count).
0800 2048 Address      3 DX1DX2BK       Address of the second level page
                                        which contains up to 128 minidisk
                                        extents. Bits 0-23 are used as an
                                        address.
0803 2051 Bitstring    1 DX1PGECT       Count of entries in a DX2BK block
                                        starting with 1. Zero indicates
                                        an empty DX2BK block.
          00000004       DX1LENE2       *-DX1DX2BK Length of this entry.
          1111 1111      DX1CTMSK       X'000000FF' Mask to isolate
                                        count.
          00FFFF00       DX1DX2AM       X'FFFFFF00' Mask to isolate DX2BK
                                        address.
0804 2052 Signed       4 DX1DX2NT (511) Next entry in this block.
          00000200       DX1NUMET       4096/(DX1LENET+DX1LENE2) Number
                                        of entries in the DX1BK.
 
 
  DX1BK Storage Layout Top of page
  
          
*** DX1BK - Minidisk extent index level 1.
*
*     +---------------------------+---------------------------+
*   0 |         DX1HPRBN          |                           |
*     +---------------------------+                           |
*   8 |                                                       |
*     =                       DX1NXTET                        =
*     |                                                       |
*     +--------------------+------+---------------------------+
* 800 |     DX1DX2BK       |:PGECT|                           |
*     +--------------------+------+                           |
* 808 |                                                       |
*     =                       DX1DX2NT                        =
*     |                                                       |
*     +-------------------------------------------------------+
*1000
*
*** DX1BK - Minidisk extent index level 1.
 
 
  DX1BK Cross Reference Top of page
  
 
Symbol         Dspl Value
-------------- ---- -----
DX1CTMSK       0803 FF
DX1DX2AM       0803 00FFFF00
DX1DX2BK       0800
DX1DX2NT       0804
DX1DX2XT       0800
DX1HPRBN       0000
DX1LENET       0000 00000004
DX1LENE2       0803 00000004
DX1NUMET       0804 00000200
DX1NXTET       0004
DX1PGECT       0803
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:50:05 EDT.
Copyright IBM Corporation, 1990, 2022