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

#### DCHBK

Prolog

Control Block Contents
DCHBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### DCHBK Prolog

     NAME       : HCPDCHBK
     DESCRIPTION: Diagnose Control Header
     DSECT      : DCHBK
     FUNCTION   : The Diagnose Control Header serializes use of the
                  diagnose control block locator array, as well as
                  locates the diagnose control block locator array.
     LOCATED BY : SYSCM.SYSDCHBK
     CREATED BY : HCPHVAIN
     DELETED BY : None.
     REFERENCES : None.
     SERIALIZED : The DCHBK is created during system initialization;
                  no further serialization is required.
                  The DCHLOCK is obtained exclusive in order to
                  serialize additions to the array of addresses of
                  DGNBKs.  Since an address in the array is never
                  deleted, there is no conflict between searching and
                  adding.  Therefore, there is no need to obtain the
                  DCHLOCK for searching.

#### DCHBK Control Block Content

#### DCHBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      DCHBK          Diagnose Control Header
    0000    0 Dbl-Word     8 DCHLOCK (3)    Lock for serializing actions on
                                            the DCHDGNIX array of addresses.
    0018   24 Address      4 DCHDGNIX       Address of the array of addresses
                                            of DGNBKs.
    001C   28 Address      4 *              Reserved
    0020   32 Dbl-Word     8 DCH$END (0)    The end

#### DCHBK Storage Layout

    *** DCHBK - Diagnose Control Header
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       DCHLOCK                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    *  18 |         DCHDGNIX          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *
    *** DCHBK - Diagnose Control Header

#### DCHBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    DCH$END        0020
    DCHDGNIX       0018
    DCHLOCK        0000

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 16:47:58 EDT.
Copyright IBM Corporation, 1990, 2005