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' EXPNOP Indicates that
                                        neither a RSCH or a SSCH is
                                        required.
          00000001       EXPDQINP       X'01' EXPDQINP Indicates a
                                        DEQUEUE in progress
          00000002       EXPRSCH        X'02' EXPRSCH Indicates that a
                                        RSCH is required
          00000004       EXPSSCH        X'04' EXPSSCH Indicates that a
                                        SSCH is required
0002    2 Bitstring    1 EXPTYPEF       Exposure type flag
          ..1. ....      EXPSCSI        X'20' EXPSCSI Native SCSI (FBA on
                                        SCSI)
          .... ..1.      EXPFBA         X'02' EXPFBA This is an FBA
                                        device
          .... ...1      EXPECKD        X'01' EXPECKD 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 Signed       4 EXPDEVHI       Recent High Device Service Time
0028   40 Signed       2 EXPDEVIN       Interval count - used to manage
                                        the Recent High Device Service
                                        time
002A   42 Signed       2 EXPDEVOC       Outlier count - used to manage
                                        the Recent High Device Service
                                        time
      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 EXPOTOTL       Running total device service time
                                        for consecutive requests found to
                                        be greater than the Recent High
                                        Device Service time in EXPDEVHI
00BC  188 Signed       4 *              Reserved for IBM use
00C0  192 Dbl-Word     8 *              Reserved for IBM use
00C8  200 Signed       4 EXPBKEND (0)   End of EXPBK.
          000000C8       EXPBSIZE       *-EXPBK Size of this DSECT in
                                        Bytes
          00000019       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          |         EXPDEVHI          |
*     +-------------+-------------+---------------------------+
*  28 |  EXPDEVIN   |  EXPDEVOC   |         EXPCTPRD          |
*     +-------------+-------------+---------------------------+
*  30 |         EXPCTPWR          |         EXPCTSRD          |
*     +---------------------------+---------------------------+
*  38 |         EXPCTSWR          |         EXPCTACP          |
*     +---------------------------+---------------------------+
*  40 |         EXPCURQC          |         EXP2BQED          |
*     +---------------------------+---------------------------+
*  48 |         EXPIORBK          |         EXPCTUSI          |
*     +---------------------------+---------------------------+
*  50 |         EXPDEVST          |         EXPMLOAD          |
*     +---------------------------+---------------------------+
*  58 |         EXPTIMER          |         EXPINTIM          |
*     +---------------------------+---------------------------+
*  60 |         EXPNMPIO          |         EXPRDCBK          |
*     +---------------------------+---------------------------+
*  68 |                                                       |
*     =                       EXPCONT                         =
*     |                                                       |
*     +---------------------------+---------------------------+
*  B8 |         EXPOTOTL          |///////////////////////////|
*     +---------------------------+---------------------------+
*  C0 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*
*** EXPBK - EXPOSURE BLOCK
          
*** EXPQUENT - EXPOSURE BLOCK
*
*     +---------------------------+
*   0 |         EXPQANCH          | 4
*     +---------------------------+
*
*** EXPQUENT - EXPOSURE BLOCK

 

EXPBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
EXPBKEND       00C8
EXPBSIZE       00C8 000000C8
EXPCONT        0068
EXPCTACP       003C
EXPCTPRD       002C
EXPCTPWR       0030
EXPCTSRD       0034
EXPCTSWR       0038
EXPCTUSI       004C
EXPCURQC       0040
EXPDEVHI       0024
EXPDEVIN       0028
EXPDEVOC       002A
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
EXPOTOTL       00B8
EXPPAGBK       0048 00000048
EXPPIOHL       0010
EXPQANCH       0000
EXPQCNEG       0006
EXPRDCBK       0064
EXPRSCH        0001 00000002
EXPSCCWP       000C
EXPSCSI        0002 20
EXPSFDSV       0014
EXPSIZE        00C8 00000019
EXPSLDSV       0018
EXPSSCH        0001 00000004
EXPSTATF       0001
EXPTIMER       0058
EXPTYPEF       0002
EXP2BQED       0044

This information is based on z/VM V5R4.0. Last updated on 18 Feb 2010 at 03:55:32 EDT.
Copyright IBM Corporation, 1990, 2009