Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM. |
DPSBK
Control Block Contents
DPSBK DSECT
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
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' Supports read multiple count key data CCWs .1.. .... DPSOVFL X'40' Minidisk formatted with overflow records ..1. .... DPSFBA X'20' FBA device .... .... DPSNODEP X'00' 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
Last updated on 5 Jun 2001 at 13:24:44 EDT.
Copyright IBM Corporation, 1990, 2001