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

#### DOSSECT

Prolog

Control Block Contents
DOSSECT DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### DOSSECT Prolog

     Name       : DOSCB
     Description: DOS Simulation Control Block
     DSECT      : DOSSECT
     Function   : DOSSECT simulates the CMS file control block
                  (FCB) in the CMS/DOS environment. DOSSECT is
                  called by the DOSCB macro. The DOS simulation
                  control blocks are chained together. The
                  DOSFIRST field in NUCON points to the first
                  DOSCB in the chain, or if no chain exists,
                  contains zero.

#### DOSSECT Control Block Content

#### DOSSECT DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      DOSSECT        DOS Simulation Control Block
    0000    0 Bitstring    1 DOSINIT (0)    DOSCB FLAG BYTE
              .1.. ....      DOSOS          X'40' CREATED BY 'OS' USER
              ..1. ....      DOSDOS         X'20' DEFINED FOR NON-CMS DISK
              ...1 ....      DOSCMS         X'10' DEFINED FOR CMS DISK
              .... 1...      DOSDDCAT       X'08' USER CATALOG DATASET
              .... .1..      DOSPERM        X'04' PERMANENT CONTROL BLOCK
              .... ..1.      DOSJCAT        X'02' SEARCH VSAM JOB CATALOG
              .... ...1      DOSUCAT        X'01' SEARCH VSAM USER CATALOG
    0000    0 Address      4 DOSNEXT        AL3(NEXT DOSCB)
    0004    4 Character    4 DOSCBID        'DLBL' TO DISTINGUISH FROM CMSCB
    0008    8 Character    8 DOSDD          DATA DEFINITION NAME
    0010   16 Character    8 DOSOP          CMS OPERATION
    0018   24 Bitstring    1 DOSTAPID (0)   TAPE IDENTIFICATION
    0018   24 Character    8 DOSDSNAM       DATASET NAME
    0020   32 Character    8 DOSDSTYP       DATASET TYPE
    0028   40 Character    2 DOSDSMD        DATASET MODE
    002A   42 Signed       2 *              RESERVED
    002C   44 Signed       4 DOSBUFF        A(INPUT/OUTPUT BUFFER)
    0030   48 Signed       4 DOSBYTE        SIZE OF BUFFER (DATA COUNT)
    0034   52 Character    1 DOSFORM        FILE FORMAT: FIXED/VARIABLE
    0035   53 Bitstring    1 DOSEPL         EXTENDED PLIST
    0036   54 Signed       2 *              RESERVED
    0038   56 Signed       4 DOSREAD        N'BYTES ACTUALLY READ
    003C   60 Signed       4 DOSITEM        ITEM (RECORD) NUMBER
    0040   64 Signed       4 DOSCOUT        RECORDS PER CMS PHYSICAL BLOCK
    0044   68 Bitstring    1 DOSDEV         DEVICE TYPE CODE
              .... ....      DOSDUM         0 DUMMY DEVICE
              ...1 .1..      DOSDSK         20 DISK
    0045   69 Bitstring    1 DOSTAPMD       RESERVED - This field is no
                                            longer used and considered
                                            undefined
    0046   70 Signed       2 DOSBLKSZ       BLOCK SIZE
    0048   72 Dbl-Word     8 DOSWORK        WORK AREA
    0050   80 Signed       2 DOSYSXXX (0)   LOGICAL UNIT FOR CMS/DOS
    0050   80 Bitstring    1 DOSSYS         SYS/PROG UNIT: X'00' =SYS,
                                            X'01'=PROG
    0051   81 Bitstring    1 DOSXXX         NUMBER FROM 000-255 ASSOC WITH
                                            UNIT
    0052   82 Bitstring    1 DOSEXT         NUMBER DOS EXTENTS LEFT TO
                                            PROCESS
    0053   83 Bitstring    1 DOSEXTCT       CURRENT DOS EXTENT
    0054   84 Signed       4 DOSOSFST       POINTER TO OS FST
    0058   88 Signed       4 DOSOSDSN       POINTER TO OS DSNAME BLOCK
    005C   92 Signed       4 DOSVOLTB       A(VOLUME ID TABLE)-VSAM MULTIVOL
                                            DATASET
    0060   96 Signed       4 DOSEXTTB       A(EXTENT TABLE) FOR VSAM
                                            DATASPACE
    0064  100 Signed       2 DOSSENSE       I/O SENSE DATA
    0066  102 Bitstring    1 DOSVOLNO       NO. VOLUMES (ENTRIES IN DOSVOLTB)
    0067  103 Bitstring    1 DOSEXTNO       NO. EXTENTS (ENTRIES IN DOSEXTTB)
    0068  104 Signed       4 DOSBUFSP       SIZE OF VSAM I/O BUFFER(S)
    006C  108 Character    8 DOSUCNAM       VSAM USER CATALOG DDNAME
    0074  116 Signed       4 DOSSAVE (6)    TEMP SAVE FOR RE-ENTRANT CODE
    008C  140 Bitstring    1 DOSEXTCX       - CURRENT EXTENT (USED BY DMSXCP)
    008D  141 Character    1 DOSTYPE        - DATASET TYPE (SAM=S, VSAM=A)
    0090  144 Signed       4 DOSDTF         POINTER TO DTF
    0094  148 Signed       4 DOSF1AD        POINTER TO F1 LABEL
              00000098       DOSCCHHR       * DOS CCHHR
    0098  152 Character    2 DOSCC          DOS CC - CYLINDER
    009A  154 Character    2 DOSHH          DOS HH - TRACK
    009C  156 Character    1 DOSR           DOS R - RECORD
    009D  157 Bitstring    1 DOSINIT2       - DOSCB flag byte 2
              1... ....      DOSOSASN       X'80' OS DLBL Issued and ASSGN
                                            done.
              .1.. ....      DOSOSCLR       X'40' OS DLBL CLEAR and unASSGN
                                            needed.
    009E  158 Signed       2 *              - RESERVED FOR FUTURE USE
    00A0  160 Dbl-Word     8 DOSEND (0)     END ADDRESS OF THIS BLOCK
              00000014       DOSENSIZ       (*-DOSSECT)/8 SIZE OF BLOCK IN
                                            DBLWORDS

#### DOSSECT Storage Layout

    *** DOSSECT - DOS Simulation Control Block
    *
    *     +---------------------------+---------------------------+
    *   0 |         DOSNEXT           |         DOSCBID           |
    *     +---------------------------+---------------------------+
    *   8 |                        DOSDD                          |
    *     +-------------------------------------------------------+
    *  10 |                        DOSOP                          |
    *     +-------------------------------------------------------+
    *  18 |                       DOSDSNAM                        |
    *     +-------------------------------------------------------+
    *  20 |                       DOSDSTYP                        |
    *     +-------------+-------------+---------------------------+
    *  28 |  DOSDSMD    |/////////////|         DOSBUFF           |
    *     +-------------+-------------+------+------+-------------+
    *  30 |         DOSBYTE           |:FORM |DOSEPL|/////////////|
    *     +---------------------------+------+------+-------------+
    *  38 |         DOSREAD           |         DOSITEM           |
    *     +---------------------------+------+------+-------------+
    *  40 |         DOSCOUT           |DOSDEV|:TAPMD|  DOSBLKSZ   |
    *     +---------------------------+------+------+-------------+
    *  48 |                       DOSWORK                         |
    *     +------+------+------+------+---------------------------+
    *  50 |DOSSYS|DOSXXX|DOSEXT|:EXTCT|         DOSOSFST          |
    *     +------+------+------+------+---------------------------+
    *  58 |         DOSOSDSN          |         DOSVOLTB          |
    *     +---------------------------+-------------+------+------+
    *  60 |         DOSEXTTB          |  DOSSENSE   |:VOLNO|:EXTNO|
    *     +---------------------------+-------------+------+------+
    *  68 |         DOSBUFSP          |        DOSUCNAM-          |
    *     +---------------------------+---------------------------+
    *  70 |          -(06C)           |                           |
    *     +---------------------------+                           |
    *  78 |                                                       |
    *     =                       DOSSAVE                         =
    *     |                           +------+------+-------------+
    *  88 |                           |:EXTCX|:TYPE |/////////////|
    *     +---------------------------+------+------+-------------+
    *  90 |          DOSDTF           |         DOSF1AD           |
    *     +-------------+-------------+------+------+-------------+
    *  98 |   DOSCC     |   DOSHH     |DOSR  |:INIT2|/////////////|
    *     +-------------+-------------+------+------+-------------+
    *
    *** DOSSECT - DOS Simulation Control Block

#### DOSSECT Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    DOSBLKSZ       0046
    DOSBUFF        002C
    DOSBUFSP       0068
    DOSBYTE        0030
    DOSCBID        0004
    DOSCC          0098
    DOSCCHHR       0094 00000098
    DOSCMS         0000 10
    DOSCOUT        0040
    DOSDD          0008
    DOSDDCAT       0000 08
    DOSDEV         0044
    DOSDOS         0000 20
    DOSDSK         0044 14
    DOSDSMD        0028
    DOSDSNAM       0018
    DOSDSTYP       0020
    DOSDTF         0090
    DOSDUM         0044 00
    DOSEND         00A0
    DOSENSIZ       00A0 00000014
    DOSEPL         0035
    DOSEXT         0052
    DOSEXTCT       0053
    DOSEXTCX       008C
    DOSEXTNO       0067
    DOSEXTTB       0060
    DOSFORM        0034
    DOSF1AD        0094
    DOSHH          009A
    DOSINIT        0000
    DOSINIT2       009D
    DOSITEM        003C
    DOSJCAT        0000 02
    DOSNEXT        0000
    DOSOP          0010
    DOSOS          0000 40
    DOSOSASN       009D 80
    DOSOSCLR       009D 40
    DOSOSDSN       0058
    DOSOSFST       0054
    DOSPERM        0000 04
    DOSR           009C
    DOSREAD        0038
    DOSSAVE        0074
    DOSSENSE       0064
    DOSSYS         0050
    DOSTAPID       0018
    DOSTAPMD       0045
    DOSTYPE        008D
    DOSUCAT        0000 01
    DOSUCNAM       006C
    DOSVOLNO       0066
    DOSVOLTB       005C
    DOSWORK        0048
    DOSXXX         0051
    DOSYSXXX       0050

This information is based on z/VM V5R2.0.
Last updated on 6 Dec 2005 at 15:38:24 EDT.
Copyright IBM Corporation, 1990, 2005