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

#### EXPBK

Prolog

Control Block Contents
EXPBK DSECT
EXPQUENT DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### EXPBK Prolog

     NAME       : HCPEXPBK
     DESCRIPTION: EXPOSURE BLOCK
     DSECT      : EXPBK
     FUNCTION   : The exposure block contains necessary information
                  about a CP volume for paging information.
     LOCATED BY : CPVEXPBK - Points to the exposure block.
     CREATED BY : HCPRDAAT - When the CP owned volume is brought on
                  line at IPL time and during the ATTACH
                  command processing.
     DELETED BY : HCPRDADT - When the CP owned volume is DETACHed from
                  the system.
     SERIALIZED : EXPLCKFG - A Test and Set instruction is used to set
                  the lock flag on to serialize this control
                  block and the IORBK control block for the
                  exposure.
     COMMENTS   :

#### EXPBK Control Block Content

#### EXPBK DSECT

####

####

####

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      EXPBK          EXPOSURE BLOCK
            Flags for the exposure block.
    0000    0 Signed       4 EXPFLAGS (0)   Flags for the exposure block
    0000    0 Bitstring    1 EXPLCKFG       Exposure lock byte. X'FF' -
                                            Indicates this exposure is
                                            locked. X'00' - Indicates this
                                            exposure is available for use
              .... ....      EXPLCKRL       X'00' Used to release the
                                            exposure lock
            This flag is to keep the status information for this
          exposure.
    0001    1 Bitstring    1 EXPSTATF       Exposure status flag
              00000000       EXPNOP         X'00' Indicates that neither a
                                            RSCH or a SSCH is required.
              00000001       EXPDQINP       X'01' Indicates a DEQUEUE in
                                            progress
              00000002       EXPRSCH        X'02' Indicates that a RSCH is
                                            required
              00000004       EXPSSCH        X'04' Indicates that a SSCH is
                                            required
    0002    2 Bitstring    1 EXPTYPEF       Exposure type flag
              ..1. ....      EXPSCSI        X'20' Native SCSI (FBA on SCSI)
              .... ..1.      EXPFBA         X'02' This is an FBA device
              .... ...1      EXPECKD        X'01' Indicates this is an ECKD
                                            paging device
    0003    3 Bitstring    1 *              Reserved for future IBM use
                 Maximum number of outstanding DASD I/O for multiple
          read or writes.
    0004    4 Signed       2 EXPMAXMW       Maximum number of multiple writes
                                            that can be added into the
                                            channel program. This value is 4
                                            * number of records per track.
    0006    6 Signed       2 EXPQCNEG       Number of times EXPCURQC went
                                            neg.
           The PIOBKs for this exposure
    0008    8 Address      4 EXPFACPA       Host absolute address of the
                                            first active PIOBK.
    000C   12 Address      4 EXPSCCWP       Suspended CCW package. This is
                                            the host absolute address of the
                                            PIOBK in the current channel
                                            program that contains the
                                            suspended NOP.
    0010   16 Address      4 EXPPIOHL       Host logical address of the
                                            contiguous block of PIOBKs.
          These are deferred saveareas when all CCW packages
          are used for this exposure.  The queues are described
          in the general comments section of HCPPAGRV.
    0014   20 Address      4 EXPSFDSV       First deferred savearea for
                                            single reads and writes. (A
                                            PPIBK)
    0018   24 Address      4 EXPSLDSV       Last deferred savearea for single
                                            reads and writes. (A PPIBK)
    001C   28 Address      4 EXPMRDFQ       Host logical address of the PPIBK
                                            that contains the queue of
                                            deferred FRMTEs (PPIFRMQG) to be
                                            read for a multiple read request.
    0020   32 Address      4 EXPMWDFQ       Host logical address of the PPIBK
                                            that contains the queue of
                                            deferred FRMTEs (PPIFRMQG) to be
                                            written for a multiple write
                                            request.
    0024   36 Bitstring    8 *              Reserved for future IBM use.
          Monitor counters.
    002C   44 Signed       4 EXPCTPRD       Total count of page read
                                            operations for this device. Note
                                            that page read operations may be
                                            directed to devices without any
                                            cylinders specifically defined as
                                            type PAGE.
    0030   48 Signed       4 EXPCTPWR       Total count of page write
                                            operations for this device. Note
                                            that page write operations may be
                                            directed to devices without any
                                            cylinders specifically defined as
                                            type PAGE.
    0034   52 Signed       4 EXPCTSRD       Total count of spooling reads for
                                            this device.
    0038   56 Signed       4 EXPCTSWR       Total count of spooling writes
                                            for this device.
    003C   60 Signed       4 EXPCTACP       Total count of paging/spooling
                                            reads and writes added to an
                                            existing channel program without
                                            executing a SSCH or RSCH.
    0040   64 Signed       4 EXPCURQC       Cardinal count of all outstanding
                                            paging/spooling reads/writes for
                                            this device.
    0044   68 Signed       4 EXP2BQED       Count of slots that have been
                                            assigned on this CPVOL but have
                                            not yet been added to EXPCURQC,
                                            updated using CS logic
    0048   72 Address      4 EXPIORBK       IORBK for this exposure. The
                                            IORBK is always at the beginning
                                            of each PAGBK so this field
                                            doubles as the PAGBK address
              00000048       EXPPAGBK       EXPIORBK,4 PAGBK for this
                                            exposure
    004C   76 Signed       4 EXPCTUSI       Total count of the number of
                                            times the channel program had to
                                            be terminated to allow user I/O.
                                            This is an indicator of
                                            interference between user and
                                            paging/spooling I/O.
    0050   80 Signed       4 EXPDEVST       Exposure service time.
    0054   84 Signed       4 EXPMLOAD       Exposure MLOAD.
    0058   88 Signed       4 EXPTIMER       Exposure timestamp for SSCH/RSCH.
    005C   92 Signed       4 EXPINTIM       Exposure timestamp at I/O
                                            interrupt time.
    0060   96 Signed       4 EXPNMPIO       Number of active PIOBKS at I/O
                                            interrupt time used to calc
                                            service time.
    0064  100 Address      4 EXPRDCBK       Address of the RDCBK.
    0068  104 Signed       4 EXPCONT (20)   Count of 20 contiguous free
                                            spaces allocated from 1 to 20
                                            plus.
    00B8  184 Signed       4 EXPBKEND (0)   End of EXPBK.
              000000B8       EXPBSIZE       *-EXPBK Size of this DSECT in
                                            Bytes
              00000017       EXPSIZE        (((*-EXPBK)+7)/8) Size in
                                            double-words
          The next two statements EXPQUENT, and EXPQANCH
          are used to map the multiple read and
          write queue fields EXPMRDFQ and EXPMWDFQ.

    EXPQUENT DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      EXPQUENT       EXPOSURE BLOCK
    0000    0 Address      4 EXPQANCH       Anchor for multiple defer queues.

    EXPBK Storage Layout

    *** EXPBK - EXPOSURE BLOCK
    *
    *     +------+------+------+------+-------------+-------------+
    *   0 |:LCKFG|:STATF|:TYPEF|//////|  EXPMAXMW   |  EXPQCNEG   |
    *     +------+------+------+------+-------------+-------------+
    *   8 |         EXPFACPA          |         EXPSCCWP          |
    *     +---------------------------+---------------------------+
    *  10 |         EXPPIOHL          |         EXPSFDSV          |
    *     +---------------------------+---------------------------+
    *  18 |         EXPSLDSV          |         EXPMRDFQ          |
    *     +---------------------------+---------------------------+
    *  20 |         EXPMWDFQ          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  28 |///////////////////////////|         EXPCTPRD          |
    *     +---------------------------+---------------------------+
    *  30 |         EXPCTPWR          |         EXPCTSRD          |
    *     +---------------------------+---------------------------+
    *  38 |         EXPCTSWR          |         EXPCTACP          |
    *     +---------------------------+---------------------------+
    *  40 |         EXPCURQC          |         EXP2BQED          |
    *     +---------------------------+---------------------------+
    *  48 |         EXPIORBK          |         EXPCTUSI          |
    *     +---------------------------+---------------------------+
    *  50 |         EXPDEVST          |         EXPMLOAD          |
    *     +---------------------------+---------------------------+
    *  58 |         EXPTIMER          |         EXPINTIM          |
    *     +---------------------------+---------------------------+
    *  60 |         EXPNMPIO          |         EXPRDCBK          |
    *     +---------------------------+---------------------------+
    *  68 |                                                       |
    *     =                       EXPCONT                         =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *
    *** EXPBK - EXPOSURE BLOCK

    *** EXPQUENT - EXPOSURE BLOCK
    *
    *     +---------------------------+
    *   0 |         EXPQANCH          | 4
    *     +---------------------------+
    *
    *** EXPQUENT - EXPOSURE BLOCK

    EXPBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    EXPBKEND       00B8
    EXPBSIZE       00B8 000000B8
    EXPCONT        0068
    EXPCTACP       003C
    EXPCTPRD       002C
    EXPCTPWR       0030
    EXPCTSRD       0034
    EXPCTSWR       0038
    EXPCTUSI       004C
    EXPCURQC       0040
    EXPDEVST       0050
    EXPDQINP       0001 00000001
    EXPECKD        0002 01
    EXPFACPA       0008
    EXPFBA         0002 02
    EXPFLAGS       0000
    EXPINTIM       005C
    EXPIORBK       0048
    EXPLCKFG       0000
    EXPLCKRL       0000 00
    EXPMAXMW       0004
    EXPMLOAD       0054
    EXPMRDFQ       001C
    EXPMWDFQ       0020
    EXPNMPIO       0060
    EXPNOP         0001 00000000
    EXPPAGBK       0048 00000048
    EXPPIOHL       0010
    EXPQANCH       0000
    EXPQCNEG       0006
    EXPRDCBK       0064
    EXPRSCH        0001 00000002
    EXPSCCWP       000C
    EXPSCSI        0002 20
    EXPSFDSV       0014
    EXPSIZE        00B8 00000017
    EXPSLDSV       0018
    EXPSSCH        0001 00000004
    EXPSTATF       0001
    EXPTIMER       0058
    EXPTYPEF       0002
    EXP2BQED       0044

    This information is
    based on z/VM V5R2.0.
    Last updated on 12 Apr 2006 at 17:13:57 EDT.

    Copyright IBM Corporation, 1990, 2005