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

#### OFBK

Prolog

Control Block Contents
OFBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### OFBK Prolog

     Name       : HCPOFBK
     Description: CP Open File Block
     COPYRIGHT -
                  THIS MODULE IS "RESTRICTED MATERIALS OF IBM"
                  LICENSED MATERIALS - PROPERTY OF IBM
                  5654-A17 (C) COPYRIGHT IBM CORP. - 1995, 2001
     DSECT      : OFBK
     Function   : The OFBK contains information about each
                  open CMS file on CP accessed minidisks
     Located by : ACSBK.ACSOFB
                  OFBK.OFBFWD
                  DRBK.DRBOFB
     Created by : HCPZIA
                  HCPZIO
     Deleted by : HCPZIC
                  HCPZIR

#### OFBK Control Block Content

#### OFBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      OFBK           CP Open File Block
    0000    0 Address      4 OFBFWD         A( next OFB )
    0004    4 Address      4 OFBDRB         A( chain of open DRBKs )
    0008    8 Address      4 OFBRFSB        R-addr of FSB
    000C   12 Address      4 OFBVFSB        V-addr of FSB
    0010   16 Address      4 OFBMLEBK       Address of MLEBK chain
    0014   20 Signed       4 *              Reserved for future IBM use
    0018   24 Signed       4 *              Reserved for future IBM use
    001C   28 Signed       4 *              Reserved for future IBM use
    0020   32 Signed       2 OFBSIZE        Size of OFBK in bytes
    0022   34 Bitstring    1 OFBFLAG1       Flags
              1... ....      OFBSEUDO       X'80' This is a Pseudo-OPEN OFBK
              ...1 ....      OFBUNIQE       X'10' Only 1 OPEN against this
                                            OFBK
    0023   35 Bitstring    1 OFBFLAG2       Flags
              1... ....      OFBOUTPT       X'80' This is an output OFBK
              .... ...1      OFBDATA        X'01' OFBRBUFF must be written
    0024   36 Address      4 OFBIOR         A( IORBK, if any )
    0028   40 Dbl-Word     8 OFBLOCK (3)    Lock for file I/O
    0040   64 Signed       4 OFBUSER1       Reserved for non-IBM use
    0044   68 Signed       4 OFBUSER2       Reserved for non-IBM use
    0048   72 Dbl-Word     8 OFBPTRS (0)    Start of variable length data
                                            Pointers to DASD blocks
              00000048       OFBSIZEB       (*-OFBK+7)/8*8 Size in bytes
              00000009       OFBSIZED       (*-OFBK+7)/8 Size in d-words
         This section is subscripted (0:FSB#LVL)
    0048   72 Dbl-Word     8 OFBPTR (0)     Pointers to DASD blocks
    0048   72 Signed       4 OFBBLOCK       Disk block number of block
    004C   76 Signed       4 OFBSCRPT       Subscript to child pointer
    0050   80 Address      4 OFBRBUFF       R-addr of block
    0054   84 Address      4 OFBVBUFF       V-addr of block When we page-in
                                            and lock these file I/O buffers,
                                            this address will have its high
                                            order bit turned on. This
                                            technique is used principally to
                                            detect the condition where some
                                            of these buffers were properly
                                            paged-in and locked but another
                                            failed due to a paging error.
                                            Only those buffers that have this
                                            bit on will be unlocked.
    0058   88 Dbl-Word     8 * (0)          Round up to d-word boundary
              00000010       OFBPTRL        *-OFBPTR Length of these fields

#### OFBK Storage Layout

    *** OFBK - CP Open File Block
    *
    *     +---------------------------+---------------------------+
    *   0 |          OFBFWD           |          OFBDRB           |
    *     +---------------------------+---------------------------+
    *   8 |         OFBRFSB           |         OFBVFSB           |
    *     +---------------------------+---------------------------+
    *  10 |         OFBMLEBK          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  18 |///////////////////////////|///////////////////////////|
    *     +-------------+------+------+---------------------------+
    *  20 |  OFBSIZE    |:FLAG1|:FLAG2|          OFBIOR           |
    *     +-------------+------+------+---------------------------+
    *  28 |                                                       |
    *     =                       OFBLOCK                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    *  40 |         OFBUSER1          |         OFBUSER2          |
    *     +---------------------------+---------------------------+
    *
    *** OFBK - CP Open File Block

    *** Overlay for OFBPTRS in OFBK
    *
    *     +---------------------------+---------------------------+
    *  48 |         OFBBLOCK          |         OFBSCRPT          |
    *     +---------------------------+---------------------------+
    *  50 |         OFBRBUFF          |         OFBVBUFF          |
    *     +---------------------------+---------------------------+
    *  58
    *
    *** Overlay for OFBPTRS in OFBK

#### OFBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    OFBBLOCK       0048
    OFBDATA        0023 01
    OFBDRB         0004
    OFBFLAG1       0022
    OFBFLAG2       0023
    OFBFWD         0000
    OFBIOR         0024
    OFBLOCK        0028
    OFBMLEBK       0010
    OFBOUTPT       0023 80
    OFBPTR         0048
    OFBPTRL        0058 00000010
    OFBPTRS        0048
    OFBRBUFF       0050
    OFBRFSB        0008
    OFBSCRPT       004C
    OFBSEUDO       0022 80
    OFBSIZE        0020
    OFBSIZEB       0048 00000048
    OFBSIZED       0048 00000009
    OFBUNIQE       0022 10
    OFBUSER1       0040
    OFBUSER2       0044
    OFBVBUFF       0054
    OFBVFSB        000C

This information is based on z/VM V4R3.0. Last updated on 30 Apr 2002 at 17:04:18 EDT.
Copyright IBM Corporation, 1990, 2002