SHRBK Back to Index page
 
Prolog 
Control Block Contents 
   SHRBK 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.


  SHRBK Prolog Top of page
 
 NAME       : HCPSHRBK
 DESCRIPTION: SHARE BLOCK
 DSECT      : SHRBK
 FUNCTION   : This block is used to keep track of each NSS or DCSS
              that a user is attached to.
 LOCATED BY : All SHRBKs for the NSS and/or DCSSs that the
              virtual machine user is accessing are chained
              together in a list anchored off the VMDBK.
              VMDSHRPT is the pointer to the first SHRBK
              for this user.  A zero pointer indicates
              that the user's chain is empty.
              SHRFWDPT is the pointer to the next SHRBK
              in the user's chain. The chain end is
              indicated when SHRFWDPT is zero.
              - All SHRBKs for users using a specific SNTBK are
              chained together in a doubly linked list
              anchored off the SNTBK.  This list represents
              all users who have loaded the NSS or DCSS.
              SNTSHRPT is the pointer to the first SHRBK
              in the chain for this SNTBK.  A zero pointer
              indicates that the chain is empty.
              SHRQUEFW is the pointer to the next SHRBK
              in the chain for this SNTBK.  The chain end
              is indicated when SHRQUEFW is zero.
              SHRQUEBK is the pointer to the previous SHRBK
              in the chain for this SNTBK.
 CREATED BY : HCPNSL when loading an NSS or DCSS.
 DELETED BY : HCPNSP - when the user purges the DCSS.
              HCPNSP - when the user IPLs a system, all
              SHRBKs for that user are purged.
 RELOCATION CONSIDERATIONS : None
 COMMENTS   : None.
 
 
  SHRBK Control Block Content Top of page
 

 SHRBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure SHRBK SHARE BLOCK 0000 0 Address 4 SHRFWDPT Forward pointer to this user's next SHRBK. 0004 4 Address 4 SHRSNTPT Pointer to the SNTBK for this NSS or DCSS. 0008 8 Character 8 SHRNAME The name for this NSS or DCSS. 0010 16 Signed 4 SHRFLAGS (0) Flags for SHRBK. 0010 16 Bitstring 1 SHRTYPE Type information byte. .... ...1 SHREXCL X'01' SHREXCL This bit indicates that the NSS or DCSS is an exclusive copy. 0011 17 Bitstring 1 * (3) Reserved for IBM use. 0014 20 Address 4 SHRVMDBK @ of VMDBK that owns this SHRBK. 0018 24 Address 4 SHRQUEFW Next SHRBK on a chain of SHRBKs associated with a specific SNTBK. 001C 28 Address 4 SHRQUEBK Prev.SHRBK on a chain of SHRBKs associated with a specific SNTBK. 0020 32 Address 4 SHRLSSA Address of the SNTBK defining the segment space through which the named member segment was loaded. When this field is equal to SHRSNTPT, SHRNAME is not a member segment. It is a named saved segment or segment space. 0024 36 Signed 4 * Reserved for IBM use 00000005 SHRSIZE ((*-SHRBK+7)/8) Block in double words.
 
 
  SHRBK Storage Layout Top of page
 
 
*** SHRBK - SHARE BLOCK
*
*     +---------------------------+---------------------------+
*   0 |         SHRFWDPT          |         SHRSNTPT          |
*     +---------------------------+---------------------------+
*   8 |                       SHRNAME                         |
*     +------+--------------------+---------------------------+
*  10 |:TYPE |////////////////////|         SHRVMDBK          |
*     +------+--------------------+---------------------------+
*  18 |         SHRQUEFW          |         SHRQUEBK          |
*     +---------------------------+---------------------------+
*  20 |         SHRLSSA           |///////////////////////////|
*     +---------------------------+---------------------------+
*  28
*
*** SHRBK - SHARE BLOCK
 
 
  SHRBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
SHREXCL        0010 01
SHRFLAGS       0010
SHRFWDPT       0000
SHRLSSA        0020
SHRNAME        0008
SHRQUEBK       001C
SHRQUEFW       0018
SHRSIZE        0024 00000005
SHRSNTPT       0004
SHRTYPE        0010
SHRVMDBK       0014
 
This information is based on z/VM 6.4.0 Last updated on 24 Aug 2016 at 09:43:22 EDT.
Copyright IBM Corporation, 1990, 2016