RTHBK Back to Index page
 
Prolog 
Control Block Contents 
   RTHBK DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  RTHBK Prolog Top of page
 
 NAME       : HCPRTHBK
 DESCRIPTION: RECORDING TABLE HEADER BLOCK
 DSECT      : RTHBK
 FUNCTION   : MAPS OUT THE HEADER INFORMATION ON THE RECORDING
              SYSTEM SERVICE TABLE
 LOCATED BY : SYSRECQU
 SERIALIZED : SYSRECLK
 RELOCATION CONSIDERATIONS : None
 COMPATIBILITY AND MIGRATION CONCERNS : 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 RTHVERS field.)
 
 
  RTHBK Control Block Content Top of page
 

 RTHBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure RTHBK RECORDING TABLE HEADER BLOCK 0000 0 Signed 4 RTHQUE ADDRESS OF THE FIRST SYSTEM RECORD ON THE RECORDING QUEUE. 0004 4 Signed 2 * RESERVED 0006 6 Signed 2 * RESERVED. Previously: RTHMSGN field NOTES : The following field is used to indicate when the RTHBK format has changed and what that change was due to. Any code defined here should be checked in HCPRECKP when old format RTHBK is read from the checkpoint cylinders. The old format RTHBK should then be updated appropriately to the new format. Code should also be added to HCPRIURI to set the code for the RTHBK that is being newly created AFTER the format change. A new code should only need to be defined here when a change to the RTHBK causes it to be incompatible with a previous format. Due to compatibility, the displacement of the RTHVERS field 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'. 0008 8 Bitstring 1 RTHVERS RTHBK Version indicator 00000000 RTHVN00 X'00' RTHVN00 For version 00, original format 00000001 RTHVN01 X'01' RTHVN01 For version 01, Full Page RTHBK 0009 9 Bitstring 1 RTHRID RECORDING TABLE IDENTIFIER. SET TO X'FF' AT INITIALIZATION TIME. 000A 10 Signed 2 RTHFRESZ RTHBK BLOCK SIZE IN DOUBLE WORDS 000C 12 Bitstring 1 RTHFLAG RECORDING TABLE FLAGS. 1... .... RTHRINIT X'80' RTHRINIT PURGE IN PROGRESS .1.. .... RTHRINC X'40' RTHRINC I/O COMPLETE IN PROGRESS 000D 13 Bitstring 1 * RESERVED 000E 14 Signed 2 RTHDCNT LENGTH OF RTHDATA IN BYTES. RTHDATA IS MAPPED OUT INTO INDIVIDUAL RECORDING TABLE ENTRIES WITH THE RECBK DSECT. 0010 16 Character 1 RTHDATA (0) FIRST RECBK ENTRY IN THE RECORDING TABLE. COMMON EQUATES OFFSET TO RECBK WORK AREA IN RECORDING TABLE. 00000FB0 RTHRECWK (100*RECBLEN)+(RTHDATA-RTHBK) OFFSET TO RSSBK WORK AREA IN RECORDING TABLE. 00000FD8 RTHRSSWK RTHRECWK+RECBLEN SIZE OF THE RTHBK (RECORDING TABLE) IN DOUBLE WORDS 000001FE RTHDWRDS (RTHRSSWK+RSSBLEN+7)/8 SIZE OF RTHDATA IN BYTES. 00000FE0 RTHDATAB (RTHDWRDS*8)-(RTHDATA-RTHBK)
 
 
  RTHBK Storage Layout Top of page
 
 
*** RTHBK - RECORDING TABLE HEADER BLOCK
*
*     +---------------------------+-------------+-------------+
*   0 |          RTHQUE           |/////////////|/////////////|
*     +------+------+-------------+------+------+-------------+
*   8 |:VERS |RTHRID|  RTHFRESZ   |:FLAG |//////|  RTHDCNT    |
*     +------+------+-------------+------+------+-------------+
*
*** RTHBK - RECORDING TABLE HEADER BLOCK
 
 
  RTHBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
RTHDATA        0010
RTHDATAB       0010 00000FE0
RTHDCNT        000E
RTHDWRDS       0010 000001FE
RTHFLAG        000C
RTHFRESZ       000A
RTHQUE         0000
RTHRECWK       0010 00000FB0
RTHRID         0009
RTHRINC        000C 40
RTHRINIT       000C 80
RTHRSSWK       0010 00000FD8
RTHVERS        0008
RTHVN00        0008 00000000
RTHVN01        0008 00000001
 
This information is based on z/VM 6.4.0 Last updated on 24 Aug 2016 at 09:42:57 EDT.
Copyright IBM Corporation, 1990, 2016