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

NDMBK

Prolog  

Control Block Contents  
   NDMBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


NDMBK Prolog

 NAME       : HCPNDMBK
 DESCRIPTION: Network Device Message Block
 DSECT      : NDMBK
 FUNCTION   :
                Define a structure to represent a Network Device Message.
                One NDMBK exists for to represent each message frame
                created for a Network Interface Device (NID).
 LOCATED BY -
                NIDNDMHD = Pointer to the first NDMBK for the device.
                NIDNDMTL = Pointer to the last NDMBK for the device.
 CREATED BY :
                Receipt of a message for a Network Interface Device.
 DELETED BY :
                Delivery of a message for a Network Interface Device.

 

NDMBK Control Block Content


NDMBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      NDMBK          Network Device Message Block
     Chain pointers (maintained by the NDMBK user).
0000    0 Address      4 NDMFPNT        Pointer to Next NDMBK
0004    4 Address      4 NDMBPNT        Pointer to Previous NDMBK
     Static attributes (maintained by the support routines).
0008    8 Bitstring    1 NDMATTR        Message Attributes
          1... ....      NDMALLOC       X'80' - Storage was allocated
          .1.. ....      NDMFRAME       X'40' - Allocated a 4K frame
          ..1. ....      NDMSHARE       X'20' - This is a shared data
                                        area
          ...1 ....      NDMCLONE       X'10' - This is a CLONE
0009    9 Bitstring    3 *              Reserved
000C   12 Signed       4 NDMSPEC (0)
     Normal message attributes.
     ******* ORG NDMSPEC Overlay for a Normal message
000C   12 Address      4 NDMBUFAD       Pointer to Original Buffer
0010   16 Signed       4 NDMBYTES       Length of message in bytes
0014   20 Address      4 NDMDATA        Pointer to message data
     Primary message (referenced by a clone).
000C   12 Address      4 *              (NDMBUFAD) Pointer to Original
                                        Buffer
0010   16 Signed       4 NDMRFCTR       Reference Counter
0014   20 Bitstring    4 *              Reserved
     Cloned message (referencing a Primary message).
000C   12 Address      4 NDMORIG        Pointer to Primary NDMBK
0010   16 Signed       4 *              (NDMBYTES) Length of message in
                                        bytes
0014   20 Address      4 *              (NDMDATA) Pointer to message data
     End of NDMBK structure.
0018   24 Bitstring    1 NDM$END (0)    End of NDMBK
          00000018       NDMBKLN        *-NDMBK Length of NICBK in bytes
          00000003       NDMBKSZ        (*-NDMBK+7)/8 Size of NICBK in
                                        doublewords

 

NDMBK Storage Layout

          
*** NDMBK - Network Device Message Block
*
*     +---------------------------+---------------------------+
*   0 |         NDMFPNT           |         NDMBPNT           |
*     +------+--------------------+---------------------------+
*   8 |:ATTR |////////////////////|         NDMBUFAD          |
*     +------+--------------------+---------------------------+
*  10 |         NDMBYTES          |         NDMDATA           |
*     +---------------------------+---------------------------+
*  18
*
*** NDMBK - Network Device Message Block
          
*** Overlay for NDMSPEC in NDMBK
*
*                                 +---------------------------+
*   8 ...                       C |///////////////////////////|
*     +---------------------------+---------------------------+
*  10 |         NDMRFCTR          |///////////////////////////|
*     +---------------------------+---------------------------+
*  18
*
*** Overlay for NDMSPEC in NDMBK
          
*** Overlay for NDMSPEC in NDMBK
*
*                                 +---------------------------+
*   8 ...                       C |         NDMORIG           |
*     +---------------------------+---------------------------+
*  10 |///////////////////////////|///////////////////////////|
*     +---------------------------+---------------------------+
*
*** Overlay for NDMSPEC in NDMBK

 

NDMBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
NDM$END        0018
NDMALLOC       0008 80
NDMATTR        0008
NDMBKLN        0018 00000018
NDMBKSZ        0018 00000003
NDMBPNT        0004
NDMBUFAD       000C
NDMBYTES       0010
NDMCLONE       0008 10
NDMDATA        0014
NDMFPNT        0000
NDMFRAME       0008 40
NDMORIG        000C
NDMRFCTR       0010
NDMSHARE       0008 20
NDMSPEC        000C

This information is based on z/VM V4R2.0. Last updated on 30 Oct 2001 at 13:35:18 EDT.
Copyright IBM Corporation, 1990, 2001