Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### RSSBK

Prolog

Control Block Contents
RSSBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### RSSBK Prolog

     NAME       : HCPRSSBK
     DESCRIPTION: RECORDING SYSTEM SERVICE BLOCK
     DSECT      : RSSBK
     FUNCTION   : MAPS OUT THE HEADER OF SYSTEM RECORDS ON THE
                  RECORDING QUEUE.
     LOCATED BY : RTHQUE
                  RSSNEXT CHAINED
     DELETED BY : HCPREC
     NOTES      : This control block gets checkpointed during SHUTDOWN and
                  will be read back in during a WARM start.  Therefore, if
                  the format of the block changes due to service being
                  applied before the warm start, code should be in place to
                  distinguish between the old and new format.  (See the
                  note below describing the RSSVERS field.)

#### RSSBK Control Block Content

#### RSSBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      RSSBK          RECORDING SYSTEM SERVICE BLOCK
    0000    0 Signed       4 RSSNEXT        POINTER TO NEXT RSSBK
    0004    4 Signed       2 RSSUSCNT       SYSTEM RECORD USE COUNT
    0006    6 Signed       2 RSSVN00M (0)   PLACE HOLDER (VERSION 00 INFO)
    0006    6 Signed       2 *              RESERVED
    0008    8 Bitstring    1 *              RESERVED
    0009    9 Bitstring    1 RSSRID         SYSTEM RECORD ID. FROM GSDRID IN
                                            GSDBK
    000A   10 Signed       2 RSSFRESZ       RSSBK BLOCK SIZE IN DOUBLE WORDS
    000C   12 Bitstring    1 RSSFLAG        FLAGS DEFINED FOR RECORDING
                                            SYSTEM SERVICES
              1... ....      RSSRINIT       X'80' RECORD INITIALIZED TO
                                            RECORDING TABLE
              .1.. ....      RSSRINC        X'40' RECORD INCOMPLETE
              ..1. ....      RSSNOMON       X'20' Record not monitored by
                                            Free Storage Limit Detection
                                            function NOTES : The following
                                            field is used to indicate when
                                            the RSSBK format has changed and
                                            what that change was due to. Any
                                            code defined here should be
                                            checked in HCPRECKP when old
                                            format RSSBKs are read from the
                                            checkpoint cylinders. The old
                                            format RSSBKs should then be
                                            updated appropriately to the new
                                            format. Code should also be added
                                            to HCPRIUCF and HCPRECRI to set
                                            the code for any RSSBKs that are
                                            being newly created AFTER the
                                            format change. A new code should
                                            only need to be defined here when
                                            a change to the RSSBK causes it
                                            to be incompatible with a
                                            previous format (as in the case
                                            of the RSSMSGN field being
                                            expanded from a halfword to a
                                            fullword). Due to compatibility,
                                            the displacement of RSSVERS
                                            should NEVER change. Previous
                                            versions of this control block
                                            had this field marked 'RESERVED'
                                            and the field was known to be
                                            zero. Therefore, previous
                                            versions were version X'00'. In
                                            addition, RSSFLAG should never be
                                            moved. This field is used without
                                            regard to the version of the
                                            RSSBK.
    000D   13 Bitstring    1 RSSVERS        RSSBK VERSION INDICATOR
              00000000       RSSVN00        X'00' For version 00, original
                                            format
              00000001       RSSVN01        X'01' For version 01, the RSSMSGN
                                            field was expanded from a
                                            halfword to fullword
    000E   14 Signed       2 RSSDCNT        LENGTH OF RSSDATA IN BYTES
    0010   16 Signed       4 RSSMSGN        SYSTEM RECORD MESSAGE NUMBER
    0014   20 Signed       4 *              RESERVED
    0018   24 Character    1 RSSDATA (0)    START OF VARIABLE LENGTH SYSTEM
                                            RECORD DATA
              00000018       RSSBLEN        *-RSSBK RSSBK HEADER LENGTH IN
                                            BYTES
              00000003       RSSSIZE        (*-RSSBK+7)/8 RSSBK ENTRY IN
                                            DOUBLEWORDS
          The following mapping shows what the fields changed for the
          Version 01 RSSBK looked like in Version 00.  The following
          fields are used when updating Version 00 RSSBKs to Version
          01.
    0006    6 Signed       2 RSSV00MN       RSSMSGN FIELD (Version 00 Format)
    0010   16 Character    1 RSSV00DA (0)   RSSDATA FIELD (Version 00 Format)
              00000010       RSSV00HL       *-RSSBK Length of a Version 00
                                            Header

#### RSSBK Storage Layout

    *** RSSBK - RECORDING SYSTEM SERVICE BLOCK
    *
    *     +---------------------------+-------------+-------------+
    *   0 |         RSSNEXT           |  RSSUSCNT   |/////////////|
    *     +------+------+-------------+------+------+-------------+
    *   8 |//////|RSSRID|  RSSFRESZ   |:FLAG |:VERS |  RSSDCNT    |
    *     +------+------+-------------+------+------+-------------+
    *  10 |         RSSMSGN           |///////////////////////////|
    *     +---------------------------+---------------------------+
    *
    *** RSSBK - RECORDING SYSTEM SERVICE BLOCK

    *** Overlay for RSSVN00M in RSSBK
    *
    *                                               +-------------+
    *   0 ...                                     6 |  RSSV00MN   |
    *                                               +-------------+
    *   8
    *
    *** Overlay for RSSVN00M in RSSBK

    *** Overlay for RSSMSGN in RSSBK
    *
    *
    *** Overlay for RSSMSGN in RSSBK

#### RSSBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    RSSBLEN        0018 00000018
    RSSDATA        0018
    RSSDCNT        000E
    RSSFLAG        000C
    RSSFRESZ       000A
    RSSMSGN        0010
    RSSNEXT        0000
    RSSNOMON       000C 20
    RSSRID         0009
    RSSRINC        000C 40
    RSSRINIT       000C 80
    RSSSIZE        0018 00000003
    RSSUSCNT       0004
    RSSVERS        000D
    RSSVN00        000D 00000000
    RSSVN00M       0006
    RSSVN01        000D 00000001
    RSSV00DA       0010
    RSSV00HL       0010 00000010
    RSSV00MN       0006

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 17:21:07 EDT.
Copyright IBM Corporation, 1990, 2005