Programming Interface Information:
This information is NOT
intended to be
used as Programming Interfaces of VM/ESA. It is to be used for diagnosis only. |
DVTRK
Cross Reference (Contains links to field and bit definitions)
DVTRK Prolog
NAME : HCPDVTRK DESCRIPTION: DASD Virtual TRacK list node DSECT : DVTRK FUNCTION : Contains information specific to DASD block I/O requests. To be specific, this control block contains information regarding a particular track that was accessed (for write) during the process of one CMS block i/o request. All tracks that were accessed for write have one of these control blocks created for them and these control blocks are linked together and anchored off of the DBCWK control block. LOCATED BY : DBCTFRST in the DBCWK control block. Also, any DVIENTRY that contains a block on the track represented by this DVTRK point to this control block. CREATED BY : HCPDPCUT macro in module HCPDBC DELETED BY : HCPDPSRP and/or HCPDPSCU (at cleanup time after an entire CMS block i/o request has completed). COMMENTS : None
DVTRK Control Block Content
DVTRK DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure DVTRK DASD Virtual TRacK list node 0000 0 Dbl-Word 8 * (0) Better be double word aligned! 0000 0 Address 4 DVTFORW Pointer to next DVTRK block 0004 4 Address 4 DVTTCHBK TCHBK Address 0008 8 Signed 4 DVTCOUNT Count of unscheduled i/os to track 000C 12 Signed 4 DVTTKDAT (0) Track data, copied between here and HCPDBCWK, so it MUST match 000C 12 Signed 4 DVTCDATA TCHBK Center data word contents 0010 16 Bitstring 1 DVTFILL Filler, can't be used without changes to HCPDBC since data is copied directly 0011 17 Bitstring 3 DVTDPSTF (0) DPSBK stuff about track 0011 17 Bitstring 1 DVTHIRN Highest record num on track 0012 18 Signed 2 * Reserved for IBM use 00000002 DVTTKLEN (*-DVTTKDAT+3)/4 Size of track data in words DVTRTRAK And DVTFTKEY must be grouped together 0014 20 Signed 4 DVTRTRAK Relative track for this TCHBK 0018 24 Signed 4 DVTFTKEY Key for this TCHBK DVTRTRAK And DVTFTKEY must be grouped together 001C 28 Bitstring 1 DVTFLAG Processing bits 1... .... DVTDEL X'80' Must delete this TCHBK on back end .1.. .... DVTWFAIL X'40' Write to cache not performed because track didn't exist ..1. .... DVTRDF X'20' Regular data format 001D 29 Bitstring 3 * Reserved for IBM use 0020 32 Signed 4 * Reserved for IBM use 0024 36 Signed 4 * Reserved for IBM use 0028 40 Dbl-Word 8 * (0) Must always be DWRD aligned 00000028 DVTRKLEN *-DVTRK Header size
DVTRK Storage Layout
*** DVTRK - DASD Virtual TRacK list node * * +---------------------------+---------------------------+ * 0 | DVTFORW | DVTTCHBK | * +---------------------------+---------------------------+ * 8 | DVTCOUNT | DVTCDATA | * +------+------+-------------+---------------------------+ * 10 |:FILL |:HIRN |/////////////| DVTRTRAK | * +------+------+-------------+------+--------------------+ * 18 | DVTFTKEY |:FLAG |////////////////////| * +---------------------------+------+--------------------+ * 20 |///////////////////////////|///////////////////////////| * +---------------------------+---------------------------+ * 28 * *** DVTRK - DASD Virtual TRacK list node
DVTRK Cross Reference
(contains links to field and bit definitions)Symbol Dspl Value -------------- ---- -----DVTCDATA 000C
DVTCOUNT 0008
DVTDEL 001C 80
DVTDPSTF 0011
DVTFILL 0010
DVTFLAG 001C
DVTFORW 0000
DVTFTKEY 0018
DVTHIRN 0011
DVTRDF 001C 20
DVTRKLEN 0028 00000028
DVTRTRAK 0014
DVTTCHBK 0004
DVTTKDAT 000C
DVTTKLEN 0012 00000002
DVTWFAIL 001C 40
Last updated on 3 Aug 1999 at 11:53:47 EDT.
Copyright IBM Corporation, 1990, 1999