RSHBK

Prolog  

Control Block Contents  
   RSHBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

RSHBK Prolog

 Name       : HCPRSHBK
 Description: RSPBK Header Block
 DSECT      : RSHBK
 Function   : Contains RSPBK chain header (there are three
              RSPBK chains) and locks.
 Located by : SYSPRTT field in SYSCM
              SYSPUNT field in SYSCM
              SYSRDRT field in SYSCM
 Created by : HCPRIO
 Deleted by : Never deleted

RSHBK Control Block Content

RSHBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      RSHBK          RSPBK Header Block
0000    0 Signed       4 RSHCOUNT       Count of number of RSPBKs
0004    4 Address      4 RSHANCH        Pointer to first RSPBK
     Notes : There will be three versions of the RSHBK present on any
     system. One will represent the head of the reader RSPBKs, one will
     represent the head of the printer RSPBKs and one will represent the
     head of the punch RSPBKs. They will be anchored in SYSCM at SYSRDRT,
     SYSPRTT and SYSPUNT, respectively.
     No attempt should be made to acquire the lock represented by RSHLOCK
     while an RDEV lock is held. Furthermore, if more than one of these
     locks needs to be acquired, they should be acquired in the order of
     reader, printer and punch and released in the oppposite order to
     prevent possible dead-locks.
     These locks may be acquired by threads that are holding an RDEV lock.
0008    8 Dbl-Word     8 RSHLOCK (3)    Lockwords used by HCPLCK to allow
                                        . us to manipulate RSPBK chains
0020   32 Signed       4 *              Reserved for future IBM Use
0024   36 Signed       4 *              Reserved for future IBM Use
          00000028       RSHBKLEN       *-RSHBK Length of RSHBK area

RSHBK Storage Layout

          
*** RSHBK - RSPBK Header Block
*
*     +---------------------------+---------------------------+
*   0 |         RSHCOUNT          |         RSHANCH           |
*     +---------------------------+---------------------------+
*   8 |                                                       |
*     =                       RSHLOCK                         =
*     |                                                       |
*     +---------------------------+---------------------------+
*  20 |///////////////////////////|///////////////////////////|
*     +---------------------------+---------------------------+
*  28
*
*** RSHBK - RSPBK Header Block

RSHBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
RSHANCH        0004
RSHBKLEN       0024 00000028
RSHCOUNT       0000
RSHLOCK        0008