DPSBK Back to Index page
 
Prolog 
Control Block Contents 
   DPSBK 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.


  DPSBK Prolog Top of page
 
 NAME       : HCPDPSBK
 DESCRIPTION: Dasd Programming Services Block
 DSECT      : DPSBK
 FUNCTION   : This DSECT maps each entry in the device table
              located in module HCPBST.
 LOCATED BY : HCPBSTBL in module HCPDPS is device table origin
 CREATED BY : Device table is predefined, not allocated at
              run time
 DELETED BY : Never deleted
 SERIALIZED : The device table is read only, never updated
 RELOCATION CONSIDERATIONS : None
 
 
  DPSBK Control Block Content Top of page
 

 DPSBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure DPSBK Dasd Programming Services Block 0000 0 Bitstring 1 DPSBLKSZ Supported blocksize 0001 1 Bitstring 1 DPSINDEX 3 bit representation These are the values for each element in the 3-bit maps that indicate by cylinder whether it is std, non-std, or non-cachable. Also: adding 7 to the value in this field ('std cyl size x' only) results in a shift value to calculate the number of records of size 'x' in a given amount of storage. E.G. DPSINDEX = DPSI1K = 3 => 3+7=10 => 2**10=1K. Shift number of bytes right 10 bits gives number of 1K-byte records in that storage. (4 per 4K page). 3 bit representation of sizes: 00000001 DPSI256 1 3 bits for std cyl size 256 00000002 DPSI512 2 3 bits for std cyl size 512 00000003 DPSI1K 3 3 bits for std cyl size 1K 00000004 DPSI2K 4 3 bits for std cyl size 2K 00000005 DPSI4K 5 3 bits for std cyl size 4K 00000006 DPSINS 6 3 bits for non-standard cyl 00000007 DPSINC 7 3 bits for non-cachable cyl 0002 2 Signed 2 DPSRECPC Records per cylinder for this blocksize 0004 4 Signed 2 DPSTKPC Tracks per cylinder 0006 6 Signed 2 DPSRCPTK Records per track for this blocksize 0008 8 Signed 2 DPSPGPT Pages needed to hold track 000A 10 Bitstring 1 DPSFLAG Device dependencies 1... .... DPSRMCKD X'80' DPSRMCKD Supports read multiple count key data CCWs .1.. .... DPSOVFL X'40' DPSOVFL Minidisk formatted with overflow records ..1. .... DPSFBA X'20' DPSFBA FBA device .... .... DPSNODEP X'00' DPSNODEP No dependencies 000B 11 Bitstring 1 DPSPTEIX Index to PTE set for this sz 000C 12 Bitstring 4 DPSSECTR Address of sector values for records of this blocksize 0010 16 Bitstring 1 DPSNEXT (0) Next entry in device table 00000004 DPSSHIFT 4 Size of the DPSBK as a shift value (power of 2). 2**4=16=DPSSIZEB
 
 
  DPSBK Storage Layout Top of page
 
          
*** DPSBK - Dasd Programming Services Block
*
*     +------+------+-------------+-------------+-------------+
*   0 |:BLKSZ|:INDEX|  DPSRECPC   |  DPSTKPC    |  DPSRCPTK   |
*     +------+------+------+------+-------------+-------------+
*   8 |  DPSPGPT    |:FLAG |:PTEIX|         DPSSECTR          |
*     +-------------+------+------+---------------------------+
*
*** DPSBK - Dasd Programming Services Block
 
 
  DPSBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
DPSBLKSZ       0000
DPSFBA         000A 20
DPSFLAG        000A
DPSINC         0001 00000007
DPSINDEX       0001
DPSINS         0001 00000006
DPSI1K         0001 00000003
DPSI2K         0001 00000004
DPSI256        0001 00000001
DPSI4K         0001 00000005
DPSI512        0001 00000002
DPSNEXT        0010
DPSNODEP       000A 00
DPSOVFL        000A 40
DPSPGPT        0008
DPSPTEIX       000B
DPSRCPTK       0006
DPSRECPC       0002
DPSRMCKD       000A 80
DPSSECTR       000C
DPSSHIFT       0010 00000004
DPSTKPC        0004
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:49:45 EDT.
Copyright IBM Corporation, 1990, 2022