DPSBK

Prolog  

Control Block Contents  
   DPSBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

DPSBK Prolog

 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

DPSBK DSECT

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

          
*** DPSBK - Dasd Programming Services Block
*
*     +------+------+-------------+-------------+-------------+
*   0 |:BLKSZ|:INDEX|  DPSRECPC   |  DPSTKPC    |  DPSRCPTK   |
*     +------+------+------+------+-------------+-------------+
*   8 |  DPSPGPT    |:FLAG |:PTEIX|         DPSSECTR          |
*     +-------------+------+------+---------------------------+
*
*** DPSBK - Dasd Programming Services Block

DPSBK Cross Reference

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