IMGBK Back to Index page
 
Prolog 
Control Block Contents 
   IMGBK DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  IMGBK Prolog Top of page
  
 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.
 RELOCATION CONSIDERATIONS : None
 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 Top of page
  




 IMGBK DSECT
Top of page


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 Top of page
  
          
*** 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 Top of page
  
 
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 7.3.0 Last updated on 22 Jun 2022 at 15:51:25 EDT.
Copyright IBM Corporation, 1990, 2022