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

#### BKIBK

Prolog

Control Block Contents
BKIBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### BKIBK Prolog

     NAME       : HCPBKIBK
     DESCRIPTION: Block I/O Block for DIAGNOSE X'250'
     DSECT      : BKIBK
     FUNCTION   : Main control block for the DIAGNOSE X'250'
                  function; all other information can be found
                  from this block.
     LOCATED BY : VDEVBKIA
     CREATED BY : HCPBICIN, during the initialization of the
                  DIAGNOSE X'250' block I/O environment
     DELETED BY : HCPBICRE, during the removal of the
                  DIAGNOSE X'250' block I/O environment
     SERIALIZED : The block I/O block lock, BKILOCK.
     COMMENTS   : Refer to the description of the VDEVBKIA
                  field for information on the serialization
                  for pointing to this block from the
                  appropriate VDEV. There is one BKIBK for
                  each VDEV for which a DIAGNOSE X'250'
                  environment is initialized.

#### BKIBK Control Block Content

#### BKIBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      BKIBK          Block I/O Block for DIAGNOSE X'250'
    0000    0 Bitstring    1 BKISTAT        Block I/O function status
              .1.. ....      BKIRESET       X'40' BKIRESET A reset operation
                                            is pending. Note: this flag is
                                            set for serviceability - it is
                                            not checked, since BKIRMPD is
                                            always set as well by the time
                                            reset/remove status needs to be
                                            recognized.
    0001    1 Bitstring    1 BKIFLAGS       Device status flags
              .... .1..      BKIRMPD        X'04' BKIRMPD A REMOVE request is
                                            pending
              .... ...1      BKIDEVRD       X'01' BKIDEVRD Virtual device is
                                            read only
    0002    2 Bitstring    2 *              Reserved for IBM use
                 BKIDBCCT indicates processes in HCPDBC.  It is used
                 to indicate that outstanding i/o is being done
                 maybe by the minidisk cache i/o handler.
                 Thus BKIDBIRQ and BKIDBCCT BOTH must be 0 to indicate
                 there is no outstanding Diag 250 for this device.
    0004    4 Signed       4 BKIDBCCT       Count of processes in HCPDBC
    0008    8 Signed       4 BKIDBIRQ       Chain of outstanding DBIRQs
    000C   12 Signed       4 BKIDBCWK       Chain of outstanding i/o requests
    0010   16 Signed       4 BKIBLKSZ       Block size of user's disk
    0014   20 Signed       2 BKIVDEVN       Virtual device number
    0016   22 Bitstring    2 *              Reserved for future IBM use
    0018   24 Dbl-Word     8 BKIOFFCP       CP offset for disk
    0020   32 Dbl-Word     8 BKIOFFST       User's requested offset
    0028   40 Dbl-Word     8 BKISTART       User's starting block
    0030   48 Dbl-Word     8 BKIEND         User's ending block
    0038   56 Signed       4 BKIVDEVA       Virtual device block address
    003C   60 Signed       4 BKIDINFO       Address of device information
    0040   64 Signed       4 BKISVGBK       Caller's save block
    0044   68 Signed       4 BKIRMVMD       Address of the VMDBK on which the
                                            RESET or REMOVE was issued.
    0048   72 Dbl-Word     8 BKILOCK (3)    BKIBK lock
    0060   96 Signed       4 *              Reserved for IBM use
    0064  100 Signed       4 *              Reserved for IBM use
    0068  104 Signed       4 *              Reserved for IBM Use
    006C  108 Signed       4 *              Reserved for IBM use
              0000000E       BKISIZE        (*-BKIBK+7)/8 Length of BKIBK in
                                            DWs

#### BKIBK Storage Layout

    *** BKIBK - Block I/O Block for DIAGNOSE X'250'
    *
    *     +------+------+-------------+---------------------------+
    *   0 |:STAT |:FLAGS|/////////////|         BKIDBCCT          |
    *     +------+------+-------------+---------------------------+
    *   8 |         BKIDBIRQ          |         BKIDBCWK          |
    *     +---------------------------+-------------+-------------+
    *  10 |         BKIBLKSZ          |  BKIVDEVN   |/////////////|
    *     +---------------------------+-------------+-------------+
    *  18 |                       BKIOFFCP                        |
    *     +-------------------------------------------------------+
    *  20 |                       BKIOFFST                        |
    *     +-------------------------------------------------------+
    *  28 |                       BKISTART                        |
    *     +-------------------------------------------------------+
    *  30 |                        BKIEND                         |
    *     +---------------------------+---------------------------+
    *  38 |         BKIVDEVA          |         BKIDINFO          |
    *     +---------------------------+---------------------------+
    *  40 |         BKISVGBK          |         BKIRMVMD          |
    *     +---------------------------+---------------------------+
    *  48 |                                                       |
    *     =                       BKILOCK                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    *  60 |///////////////////////////|///////////////////////////|
    *     +---------------------------+---------------------------+
    *  68 |///////////////////////////|///////////////////////////|
    *     +---------------------------+---------------------------+
    *  70
    *
    *** BKIBK - Block I/O Block for DIAGNOSE X'250'

#### BKIBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    BKIBLKSZ       0010
    BKIDBCCT       0004
    BKIDBCWK       000C
    BKIDBIRQ       0008
    BKIDEVRD       0001 01
    BKIDINFO       003C
    BKIEND         0030
    BKIFLAGS       0001
    BKILOCK        0048
    BKIOFFCP       0018
    BKIOFFST       0020
    BKIRESET       0000 40
    BKIRMPD        0001 04
    BKIRMVMD       0044
    BKISIZE        006C 0000000E
    BKISTART       0028
    BKISTAT        0000
    BKISVGBK       0040
    BKIVDEVA       0038
    BKIVDEVN       0014

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:26:53 EDT.
Copyright IBM Corporation, 1990, 2008