PRQHD

Prolog  

Control Block Contents  
   PRQHD DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

PRQHD Prolog

 Name       : HCPPRQHD
 Description: PERSYS Persistent SYSPERM Free Storage
              Queue Header Control Block
 DSECT      : PRQHD
 Function   : Map the PERSYS persistent SYSPERM free storage
              queue header
 Located by : Resides at SYSPRQHD in SYSCM
 Created by : Created as part of SYSCM at system generation
 Deleted by : Never deleted.
 Serialized : Regular free storage frame serialization -
              FSDVMLK located at HCPRSMFL
 Comments   :
              There is only one PRQHD in the system, and it resides in
              SYSCM at SYSPRQHD.  PRQHD cannot be dynamically allocated
              or destroyed.

PRQHD Control Block Content

PRQHD DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      PRQHD          PERSYS Persistent SYSPERM Free
                                        Storage
0000    0 Address      4 PRQFWD         Forward pointer to the first
                                        PERSYS free storage frame's PSYBK
                                        header. If there are no PERSYS
                                        free storage frames on the queue,
                                        points to PRQHD itself.
0004    4 Address      4 PRQBWD         Backward pointer to the last
                                        PERSYS free storage frame's PSYBK
                                        header. If there are no PERSYS
                                        free storage frames on the queue,
                                        points to PRQHD itself.
0008    8 Signed       4 PRQFRMCT       Count of frames on queue
000C   12 Bitstring    1 PRQHSTAT       QUEUE STATUS BYTE
          1... ....      PRQHFLUX       X'80' Queue is in flux, recovery
                                        not possible
          .1.. ....      PRQHSURV       X'40' PERSYS free storage has
                                        survived a bounce from a previous
                                        IPL (this IPL is not a PERSYS
                                        "base" IPL).
000D   13 Bitstring    3 *              Reserved for IBM use
0010   16 Dbl-Word     8 * (0)
0010   16 Dbl-Word     8 PRQTODST       "Base" IPL TOD timestamp. This is
                                        the TOD timestamp of the original
                                        IPL since which PERSYS storage
                                        has survived.
          00000018       PRQLEN         *-PRQHD Length, in bytes, of
                                        PRQHD
          00000003       PRQSIZE        (*-PRQHD+7)/8 Size, in
                                        doublewords, of PRQHD

PRQHD Storage Layout

          
*** PRQHD - PERSYS Persistent SYSPERM Free Storage
*
*     +---------------------------+---------------------------+
*   0 |          PRQFWD           |          PRQBWD           |
*     +---------------------------+------+--------------------+
*   8 |         PRQFRMCT          |:HSTAT|////////////////////|
*     +---------------------------+------+--------------------+
*  10 |                       PRQTODST                        |
*     +-------------------------------------------------------+
*  18
*
*** PRQHD - PERSYS Persistent SYSPERM Free Storage

PRQHD Cross Reference

Symbol         Dspl Value
-------------- ---- -----
PRQBWD         0004
PRQFRMCT       0008
PRQFWD         0000
PRQHFLUX       000C 80
PRQHSTAT       000C
PRQHSURV       000C 40
PRQLEN         0010 00000018
PRQSIZE        0010 00000003
PRQTODST       0010