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 V6R1.0. Last updated on 18 Feb 2010 at 08:35:45 EDT.
Copyright IBM Corporation, 1990, 2008