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

#### 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

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 09:01:25 EDT.
Copyright IBM Corporation, 1990, 2008