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

#### LDVBK

Prolog

Control Block Contents
LDVBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### LDVBK Prolog

     NAME       : HCPLDVBK
     DESCRIPTION: ISFC Link Device Extension
     DSECT      : LDVBK
     FUNCTION   : This block is used to maintain status information
                  for a single physical link device.  The LNKBK contains
                  a table pointing to all active LDVBK blocks.
     LOCATED BY : LNKDEVTB  (array of pointers).  LNKDEVCT contains the
                  number of active devices, and LNKDEVMX is
                  equated to the maximum number that one link
                  can support.
                  RDEVCFDV  (pointer).
     CREATED BY : Operation of the 'ACTIVATE ISLINK' command.
     DELETED BY : Operation of the 'DEACTIVE ISLINK' command.
     SERIALIZED : The associated LNKBK lock (LNKLKWRD) must be held in
                  order to update the LNKBK (in general).  Some fields
                  are associated with I/O and are serialized by the
                  associated RDEV lock instead.

#### LDVBK Control Block Content

#### LDVBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      LDVBK          ISFC Link Device Extension
          Device identification and linkage.
    0000    0 Character    4 LDVDEVID       Printable hex device number
    0004    4 Signed       4 LDVDEVNO       Real device address
    0008    8 Address      4 LDVLNKBK       Base LNKBK addr (Hold RDEV lock)
    000C   12 Signed       4 LDVDEVIX       Link Device Index (0..n)
    0010   16 Address      4 LDVRDEV        RDEV address
    0014   20 Address      4 LDVEXTBK       Line Driver extension address
          Device status.
    0018   24 Bitstring    1 LDVDVFLG       Device Flag
              1... ....      LDVDVATT       X'80' - This device is ATTACHED
              .1.. ....      LDVDVAPL       X'40' - Attach Process lock is
                                            held
              ..1. ....      LDVDVLCK       X'20' - RDEV lock is held
    0019   25 Bitstring    1 LDVIOPND       I/O Pending Status
              1... ....      LDVSIOPD       X'80' - Start Pending
              .1.. ....      LDVINTPD       X'40' - Interrupt Pending
    001A   26 Bitstring    6 *              Reserved
          Low level I/O activity.
    0020   32 Address      4 LDVIORBK       IORBK for outgoing I/O
    0024   36 Address      4 LDVIORRF       IORBK for interrupt reflection
    0028   40 Signed       4 LDVUPARM       Latest ORB User PARM value
    002C   44 Bitstring    4 *              Reserved
          Work area for use by the interrupt handler.
          Notes      :
            This area is serialized by the RDEV lock.
    0030   48 Dbl-Word     8 LDVIWRK (0)    Space for LDVIWRK0-LDVIWRK9
    0030   48 Signed       4 LDVIWRK0       Work area
    0034   52 Signed       4 LDVIWRK1       Work area
    0038   56 Signed       4 LDVIWRK2       Work area
    003C   60 Signed       4 LDVIWRK3       Work area
    0040   64 Signed       4 LDVIWRK4       Work area
    0044   68 Signed       4 LDVIWRK5       Work area
    0048   72 Signed       4 LDVIWRK6       Work area
    004C   76 Signed       4 LDVIWRK7       Work area
    0050   80 Signed       4 LDVIWRK8       Work area
    0054   84 Signed       4 LDVIWRK9       Work area
              0000000B       LDVSIZE        (*-LDVBK+7)/8 Size, in
                                            doublewords, of LDVBK

#### LDVBK Storage Layout

    *** LDVBK - ISFC Link Device Extension
    *
    *     +---------------------------+---------------------------+
    *   0 |         LDVDEVID          |         LDVDEVNO          |
    *     +---------------------------+---------------------------+
    *   8 |         LDVLNKBK          |         LDVDEVIX          |
    *     +---------------------------+---------------------------+
    *  10 |         LDVRDEV           |         LDVEXTBK          |
    *     +------+------+-------------+---------------------------+
    *  18 |:DVFLG|:IOPND|/////////////////////////////////////////|
    *     +------+------+-------------+---------------------------+
    *  20 |         LDVIORBK          |         LDVIORRF          |
    *     +---------------------------+---------------------------+
    *  28 |         LDVUPARM          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  30 |         LDVIWRK0          |         LDVIWRK1          |
    *     +---------------------------+---------------------------+
    *  38 |         LDVIWRK2          |         LDVIWRK3          |
    *     +---------------------------+---------------------------+
    *  40 |         LDVIWRK4          |         LDVIWRK5          |
    *     +---------------------------+---------------------------+
    *  48 |         LDVIWRK6          |         LDVIWRK7          |
    *     +---------------------------+---------------------------+
    *  50 |         LDVIWRK8          |         LDVIWRK9          |
    *     +---------------------------+---------------------------+
    *  58
    *
    *** LDVBK - ISFC Link Device Extension

#### LDVBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    LDVDEVID       0000
    LDVDEVIX       000C
    LDVDEVNO       0004
    LDVDVAPL       0018 40
    LDVDVATT       0018 80
    LDVDVFLG       0018
    LDVDVLCK       0018 20
    LDVEXTBK       0014
    LDVINTPD       0019 40
    LDVIOPND       0019
    LDVIORBK       0020
    LDVIORRF       0024
    LDVIWRK        0030
    LDVIWRK0       0030
    LDVIWRK1       0034
    LDVIWRK2       0038
    LDVIWRK3       003C
    LDVIWRK4       0040
    LDVIWRK5       0044
    LDVIWRK6       0048
    LDVIWRK7       004C
    LDVIWRK8       0050
    LDVIWRK9       0054
    LDVLNKBK       0008
    LDVRDEV        0010
    LDVSIOPD       0019 80
    LDVSIZE        0054 0000000B
    LDVUPARM       0028

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 17:00:46 EDT.
Copyright IBM Corporation, 1990, 2005