Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

QDGBL

Prolog  

Control Block Contents  
   QDGBL DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


QDGBL Prolog

 Name       : Virtual Disk in Storage Global Control Block
 Description: V-Disk Global Control Block
 DSECT      : QDGBL
 Function   : This control block maps the global V-Disk
              control block for the system.
 Located by : HCPSYSCM - System Common Area
 Created by : HCPQDLIN
 Deleted by : none

 

QDGBL Control Block Content


QDGBL DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      QDGBL          V-Disk Global Control Block
     Vdisk chain of MDISK blocks and allocation lockword
0000    0 Dbl-Word     8 QDGALOCK (3)   Vdisk Allocation Lockword
0018   24 Signed       4 QDGMDISK       First MDISK block for Vdisk
     Fields for keeping track of limits (in blocks)
001C   28 Signed       4 QDGSYSLM       Limit of total Vdisk allocation
0020   32 Signed       4 QDGUSRLM       Limit of size of Vdisks DEFINEd
                                        by a user (using DEFINE)
0024   36 Signed       4 QDGSYSCA       Total currently-allocated Vdisk
                                        blocks
0028   40 Signed       2 *              Reserved
002A   42 Signed       2 QDGCOUNT       Vdisk counter for addr. space
                                        name (increment and save)
002C   44 Signed       4 QDGLKCNT       Total number of LINKs to all
                                        Vdisks (includes 1 for each
                                        DEFINEd VDisk)
0030   48 Signed       4 QDGDISKS       Total number of existing Vdisks
0034   52 Signed       4 QDGSYSLD       Default of QDGSYSLM
0038   56 Signed       4 QDGUSRLD       Default of QDGUSRLM
003C   60 Bitstring    1 QDGAFLAG       'A' flag byte
          1... ....      QDGASYSC       X'80' - SYSTEM CONFIG set syslim
003D   61 Bitstring    1 * (3)          Reserved
          00000008       QDGSIZE        ((*-QDGBL+7)/8) SIZE IN DWS FOR
                                        FREE/FRET

 

QDGBL Storage Layout

          
*** QDGBL - V-Disk Global Control Block
*
*     +-------------------------------------------------------+
*   0 |                                                       |
*     =                       QDGALOCK                        =
*     |                                                       |
*     +---------------------------+---------------------------+
*  18 |         QDGMDISK          |         QDGSYSLM          |
*     +---------------------------+---------------------------+
*  20 |         QDGUSRLM          |         QDGSYSCA          |
*     +-------------+-------------+---------------------------+
*  28 |/////////////|  QDGCOUNT   |         QDGLKCNT          |
*     +-------------+-------------+---------------------------+
*  30 |         QDGDISKS          |         QDGSYSLD          |
*     +---------------------------+------+--------------------+
*  38 |         QDGUSRLD          |:AFLAG|////////////////////|
*     +---------------------------+------+--------------------+
*  40
*
*** QDGBL - V-Disk Global Control Block

 

QDGBL Cross Reference

Symbol         Dspl Value
-------------- ---- -----
QDGAFLAG       003C
QDGALOCK       0000
QDGASYSC       003C 80
QDGCOUNT       002A
QDGDISKS       0030
QDGLKCNT       002C
QDGMDISK       0018
QDGSIZE        003D 00000008
QDGSYSCA       0024
QDGSYSLD       0034
QDGSYSLM       001C
QDGUSRLD       0038
QDGUSRLM       0020

This information is based on z/VM V4R2.0. Last updated on 17 Oct 2001 at 16:13:07 EDT.
Copyright IBM Corporation, 1990, 2001