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

#### IMGBK

Prolog

Control Block Contents
IMGBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### IMGBK Prolog

     NAME       : HCPIMGBK
     DESCRIPTION: Image library/NLS Message Repository
                  Block
     DSECT      : IMGBK
     FUNCTION   : This block is used for communications
                  purposes when CP users request access
                  to an Image library or NLS message
                  repository file.
     LOCATED BY : (Images)  Pointer in RSPBK
                  (NLS)     Pointer in LNGBK
     CREATED BY : (Images)  HCPSIL - when a printer is started
                  (NLS)     HCPNLS - when the first user requests
                  the language
     DELETED BY : (Images) HCPSIL - when a printer is drained
                  (NLS)    HCPNLS - when the last user releases
                  the language
     SERIALIZED : Individual IMGBKs are serialized by holding the
                  symbolic lock on the filename of the item.
                  All image, NLS, NSS and DCSS system data files are
                  locked/unlocked with the same lockword (NSUSYMAN),
                  using entry points HCPLOCPQ/HCPLOCPD.
                  SNTBKs for image libraries and NLS files are kept
                  on the same queue, anchored in HCPIMGLK.
                  This queue is locked/unlocked via the macros
                  HCPLKIMG/HCPULIMG.
     COMMENTS   : This is a variable length control block.
                  It consists of the header information plus
                  a variable number of virtual addresses.

#### IMGBK Control Block Content

#### IMGBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      IMGBK          Image library/NLS Message Repository
    0000    0 Address      4 IMGSNTBK       Pointer to the SNTBK
    0004    4 Signed       2 IMGDWSZE       Size in doublewords of the block
    0006    6 Bitstring    1 IMGTYPFG       What type of file is this?
              .... ...1      IMGIMAGE       X'01' IMGIMAGE Image library file
              .... ..1.      IMGNLS         X'02' IMGNLS NLS Message
                                            Repository file
    0007    7 Bitstring    1 IMGFLAGS       Miscellaneous Status Flags
              .... ...1      IMGFIRST       X'01' IMGFIRST First open for
                                            this file, set and reset by
                                            HCPNSROP.
    0008    8 Address      4 IMGCPNTL       Address of a CP resident routine
                                            to be called when the last user
                                            releases the image library or NLS
                                            language file. When field is
                                            zero, no call is made.
    000C   12 Address      4 IMGLNGBK       Pointer to LNGBK for this
                                            language. (For NLS language files
                                            only; for image libraries it does
                                            not apply, and remains zero.
    0010   16 Character    8 IMGNAME        File name of the image library or
                                            NLS language file
    0018   24 Signed       4 IMGRECNO       Number of the first record to be
                                            read. Records are numbered
                                            starting from one (1).
    001C   28 Signed       4 IMGRECCT       Count of records to be read
              00000004       IMGHDRSZ       ((*-IMGBK)+7)/8 Header size in
                                            doublewords
    0020   32 Signed       4 IMGVADDR (0)   Start of variable length data
    0020   32 Signed       4 IMGVIRT        Returned system virtual address

#### IMGBK Storage Layout

    *** IMGBK - Image library/NLS Message Repository
    *
    *     +---------------------------+-------------+------+------+
    *   0 |         IMGSNTBK          |  IMGDWSZE   |:TYPFG|:FLAGS|
    *     +---------------------------+-------------+------+------+
    *   8 |         IMGCPNTL          |         IMGLNGBK          |
    *     +---------------------------+---------------------------+
    *  10 |                       IMGNAME                         |
    *     +---------------------------+---------------------------+
    *  18 |         IMGRECNO          |         IMGRECCT          |
    *     +---------------------------+---------------------------+
    *
    *** IMGBK - Image library/NLS Message Repository

    *** Overlay for IMGVADDR in IMGBK
    *
    *     +---------------------------+
    *  20 |         IMGVIRT           | 24
    *     +---------------------------+
    *
    *** Overlay for IMGVADDR in IMGBK

#### IMGBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    IMGCPNTL       0008
    IMGDWSZE       0004
    IMGFIRST       0007 01
    IMGFLAGS       0007
    IMGHDRSZ       001C 00000004
    IMGIMAGE       0006 01
    IMGLNGBK       000C
    IMGNAME        0010
    IMGNLS         0006 02
    IMGRECCT       001C
    IMGRECNO       0018
    IMGSNTBK       0000
    IMGTYPFG       0006
    IMGVADDR       0020
    IMGVIRT        0020

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:43:56 EDT.
Copyright IBM Corporation, 1990, 2008