Programming Interface Information: This page documents intended Programming
Interfaces that allow the customer to write programs to obtain the services of z/VM.

IHADECB

Prolog  

Control Block Contents  
   IHADECB DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


IHADECB Prolog

 NAME       : CMSCB
 DESCRIPTION: DATA EVENT CONTROL BLOCKS FOR
              BSAM, BISAM, BDAM, QTAM, BTAM.
 DSECT      : IHADECB
 FUNCTION   : IHADECB is the simulated data event control
              block used for CMS processing of OS macros and
              OS access methods. The IOBECBPT field in
              FCBSECT points to IHADECB.

 

IHADECB Control Block Content


IHADECB DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      IHADECB        DATA EVENT CONTROL BLOCKS FOR
0000    0 Signed       4 DECSDECB       - EVENT CONTROL BLOCK
0004    4 Signed       2 DECTYPE        - TYPE OF I/O REQUEST
          1... ....      DECBRD         X'80' - READ SF
          ..1. ....      DECBWR         X'20' - WRITE SF
0006    6 Signed       2 DECLNGTH       - LENGTH OF KEY & DATA
0008    8 Address      4 DECDCBAD       - V(DATA CONTROL BLOCK)
000C   12 Address      4 DECAREA        - V(KEY & DATA, BUFFER)
0010   16 Address      4 DECIOBPT       - V(IOB) BDAM EXTENSION
0014   20 Address      4 DECKYADR       - V(KEY)
0018   24 Address      4 DECRECPT       - V(BLOCK REFERENCE FIELD)
     SOME FREQUENTLY USED EQUATES
          00000020       DDNAM          FCBDSTYP - FILETYPE = DATA SET
                                        NAME
          ...1 ....      BLK            X'10' - RECFM=BLOCKED RECORDS
          ..1. ....      BS             X'20' - MACRF=BSAM
          ..1. ....      DA             X'20' - DSORG=DIRECT ACCESS
          1... ....      FXD            X'80' - RECFM=FIXED LENGTH
                                        RECORDS
          1... ....      IS             X'80' - DSORG=INDEXED SEQUENTIAL
          .... 1...      LOC            X'08' - MACRF=LOCATE MODE
          ...1 ....      MOV            X'10' - MACRF=MOVE MODE
          .1.. ....      PS             X'40' - DSORG=PHYSICAL SEQUENTIAL
          .... ..11      POU            X'03' - DSORG=PARTITIONED
                                        UNMOVEABLE
          .... ..1.      PO             X'02' - DSORG=PARTIONED
                                        ORGANIZATION
          1... ....      PREVIOUS       X'80' - OFLGS=PREVIOUS I/O
                                        OPERATION
          .1.. ....      QS             X'40' - MACRF=QSAM
          11.. ....      UND            X'C0' - RECFM=UNDEFIN FORMAT
                                        RECORDS
          .1.. ....      VAR            X'40' - RECFM=VARIABLE LENGTH
                                        RECORDS
          ..1. ....      ANSID          X'20' - RECFM=VARIABLE LENGTH
                                        RECS (ANSI)
          .... 1...      SPANNED        X'08' - RECFM=SPANNED

 

IHADECB Storage Layout

          
*** IHADECB - DATA EVENT CONTROL BLOCKS FOR
*
*     +---------------------------+-------------+-------------+
*   0 |         DECSDECB          |  DECTYPE    |  DECLNGTH   |
*     +---------------------------+-------------+-------------+
*   8 |         DECDCBAD          |         DECAREA           |
*     +---------------------------+---------------------------+
*  10 |         DECIOBPT          |         DECKYADR          |
*     +---------------------------+---------------------------+
*  18 |         DECRECPT          | 1C
*     +---------------------------+
*
*** IHADECB - DATA EVENT CONTROL BLOCKS FOR

 

IHADECB Cross Reference

Symbol         Dspl Value
-------------- ---- -----
ANSID          0018 20
BLK            0018 10
BS             0018 20
DA             0018 20
DDNAM          0018 00000020
DECAREA        000C
DECBRD         0004 80
DECBWR         0004 20
DECDCBAD       0008
DECIOBPT       0010
DECKYADR       0014
DECLNGTH       0006
DECRECPT       0018
DECSDECB       0000
DECTYPE        0004
FXD            0018 80
IS             0018 80
LOC            0018 08
MOV            0018 10
PO             0018 02
POU            0018 03
PREVIOUS       0018 80
PS             0018 40
QS             0018 40
SPANNED        0018 08
UND            0018 C0
VAR            0018 40

This information is based on z/VM V4R1.0.
Last updated on 12 Jul 2001 at 13:52:12 EDT.
Copyright IBM Corporation, 1990, 2001