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

DNXBK

Prolog  

Control Block Contents  
   DNXBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


DNXBK Prolog

 Name       : HCPDNXBK
 Description: Directory index block
 DSECT      : DNXBK
 Function   : The directory index block maps the header
              and entries for the various directory indices.
 Located by : DHDRUSER field of HCPDHDR
              DHDRUID  field of HCPDHDR
              DHDRGID  field of HCPDHDR
              DNXHDAD  field of HCPDHDR
 Created by : HCPDIR
              HCPUDTBI
 Deleted by : HCPUDSAT
              HCPUDSDS
              HCPUDSIN
 Comments   : This DSECT references fields in
              HCPDUNDX, so any module using this DSECT must
              also COPY HCPDUNDX.
              This DSECT is used to map the various directory
              indices.  Each mapping consists of a header portion
              and a variable number of index entries.  A given
              DNXBK will only contain a single type of entry;
              that is, entry types are never mixed in a single
              DNXBK.  This DSECT is used to map both levels of
              the 2-level indices.

 

DNXBK Control Block Content


DNXBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      DNXBK          Directory index block
0000    0 Bitstring   24 DNXHDR (0)     Header portion of index block
0000    0 Signed       4 DNXHDAD        DASD address of the next DNXBK
                                        for this index
0004    4 Signed       2 DNXHCNT        Count of entries in this block
0006    6 Signed       2 *              Reserved
0008    8 Character   16 DNXHLABL       Label for this index
          00000018       DNXHDRSZ       *-DNXHDR Length of header portion
                                        in bytes
0018   24 Bitstring    1 DNXENTRY (0)   First entry starts here ORG
                                        DNXENTRY Map an entry
0018   24 Bitstring    1 DNXGIDNT (0)   GID index entry
0018   24 Bitstring   12 DNXGIPT1 (0)   Part 1 of GID index entry
0018   24 Signed       4 DNXGID         POSIX group ID (GID)
001C   28 Character    8 DNXGINAM       POSIX group name
0024   36 Bitstring   10 DNXGIPT2 (0)   Part 2 of GID index entry
0024   36 Signed       4 DNXGICNT       Count of members in this group
0028   40 Signed       4 DNXGIDAD       DASD address of first DGRPM block
002C   44 Signed       2 DNXGIDSP       Displacement to first DGRPM block
          00000016       DNXGINSZ       *-DNXGIDNT GID entry size in
                                        bytes
0018   24 Bitstring    1 DNXUSRNT (0)   Userid index entry
0018   24 Character    8 DNXUSBIG       Largest userid in the page
                                        pointed to by DNXUSDAD
0020   32 Signed       4 DNXUSDAD       DASD address of index page
          0000000C       DNXUSNSZ       *-DNXUSRNT Userid entry size in
                                        bytes
0018   24 Bitstring    1 DNXUIDNT (0)   UID index entry
0018   24 Signed       4 DNXUIBIG       Largest UID in the page pointed
                                        to by DNXUIDAD
001C   28 Signed       4 DNXUIDAD       DASD address of index page
          00000008       DNXUINSZ       *-DNXUIDNT UID entry size in
                                        bytes
0018   24 Character    8 *              This field makes up the
                                        difference between the normal
                                        header above and the DUNDX page
                                        header (which is the same size as
                                        a DUNDX).
0020   32 Bitstring    1 DNXDUNDX (0)   DUNDX page entry (see HCPDUNDX
                                        COPY for mapping).

 

DNXBK Storage Layout

          
*** DNXBK - Directory index block
*
*     +---------------------------+-------------+-------------+
*   0 |         DNXHDAD           |  DNXHCNT    |/////////////|
*     +---------------------------+-------------+-------------+
*   8 |                       DNXHLABL                        |
*     |                                                       |
*     +---------------------------+---------------------------+
*  18 |          DNXGID           |        DNXGINAM-          |
*     +---------------------------+---------------------------+
*  20 |          -(01C)           |         DNXGICNT          |
*     +---------------------------+-------------+-------------+
*  28 |         DNXGIDAD          |  DNXGIDSP   | 2E
*     +---------------------------+-------------+
*
*** DNXBK - Directory index block
          
*** Overlay for DNXENTRY in DNXBK
*
*     +-------------------------------------------------------+
*  18 |                       DNXUSBIG                        |
*     +---------------------------+---------------------------+
*  20 |         DNXUSDAD          | 24
*     +---------------------------+
*
*** Overlay for DNXENTRY in DNXBK
          
*** Overlay for DNXENTRY in DNXBK
*
*     +---------------------------+---------------------------+
*  18 |         DNXUIBIG          |         DNXUIDAD          |
*     +---------------------------+---------------------------+
*  20
*
*** Overlay for DNXENTRY in DNXBK
          
*** Overlay for DNXENTRY in DNXBK
*
*     +-------------------------------------------------------+
*  18 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*
*** Overlay for DNXENTRY in DNXBK

 

DNXBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
DNXDUNDX       0020
DNXENTRY       0018
DNXGICNT       0024
DNXGID         0018
DNXGIDAD       0028
DNXGIDNT       0018
DNXGIDSP       002C
DNXGINAM       001C
DNXGINSZ       002C 00000016
DNXGIPT1       0018
DNXGIPT2       0024
DNXHCNT        0004
DNXHDAD        0000
DNXHDR         0000
DNXHDRSZ       0008 00000018
DNXHLABL       0008
DNXUIBIG       0018
DNXUIDAD       001C
DNXUIDNT       0018
DNXUINSZ       001C 00000008
DNXUSBIG       0018
DNXUSDAD       0020
DNXUSNSZ       0020 0000000C
DNXUSRNT       0018

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 16:51:16 EDT.
Copyright IBM Corporation, 1990, 2005