IBM: RSSBK

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.

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           |///////////////////////////|
*     +---------------------------+---------------------------+
*  18 |                                                       |
*     =                       RSSDATA                         =
*     |                                                       |
*     +-------------------------------------------------------+
*
*** RSSBK - RECORDING SYSTEM SERVICE BLOCK
*** Overlay for RSSVN00M in RSSBK
*
*                                               +-------------+
*   0 ...                                     6 |  RSSV00MN   |
*                                               +-------------+
*   8
*
*** Overlay for RSSVN00M in RSSBK
*** Overlay for RSSMSGN in RSSBK
*
*     +-------------------------------------------------------+
*  10 |                                                       |
*     =                       RSSV00DA                        =
*     |                                                       |
*     +-------------------------------------------------------+
*
*** Overlay for RSSMSGN in RSSBK