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

Prolog  

Control Block Contents  

DVTRK DSECT

Storage Layout  

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


This information is based on VM/ESA 2.4.0.
Last updated on 3 Aug 1999 at 11:53:47 EDT.
Copyright IBM Corporation, 1990, 1999