DX1BK

Prolog  

Control Block Contents  
   DX1BK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

DX1BK Prolog

 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

DX1BK DSECT

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

          
*** 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

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