Programming Interface Information: The Monitor Records are intended Programming Interfaces that allow the customer to write programs to obtain services of z/VM.

#### MRSEKSEK

Prolog
Control Block Contents
Cross Reference

#### MRSEKSEK Prolog

####

####

     DSECT NAME - SEKSEK
     FUNCTION - Map a Monitor record.
     LOCATED By -
            Through the Monitor Control Area
     REFERENCED CONTROL BLOCKS -
            MRRECHDR    Monitor Record Header
     NAME - MRSEKSEK
     DESCRIPTIVE NAME - Monitor Event Record
                        Domain 7 - Seek Domain
                        Record 1 - Seek Data
     DESCRIPTION - Record of access arm movement ("Seek I/O") on a DASD
                   device or of a set paging parameter to a cache device.
                   Generated each time an I/O channel program containing
                   seek commands(s) is executed.
                   This record contains seek data that may enable a
                   user, such as an operating system developer, to tune
                   DASD seek scheduling algorithms.  This record is NOT
                   intended for DASD load balancing.  However, it can be
                   used to tune a cached minidisk to minimize the number
                   of tracks that must be cached.
     NOTES:
     --  Because of the frequency of seek I/O operations, an extremely
         large number of this record will be generated.  For this
         reason, seek-domain monitoring should be limited to specific
         devices or a specific set of devices.
     --  The order in which the records are generated may not be the
         order in which the commands are executed by the device.
     --  The seek may not be executed by a device when there is a
         permanent device error or when branching is done in the channel
         program which bypasses segments.

    MRSEKSEK Control Block Contents

    Offsets
    Dec Hex  Type       Len  Name (Dim)             Description

      0   0  Structure   64  SEKSEK                 Start of monitor record
      0   0  Character    0  SEKSEK_MRHDR           Record header. See MRRECHDR
                                                    for details.
      0   0  Character   20  MRHDR
      0   0  Unsigned     2  MRHDRLEN               record length in bytes
      2   2  Unsigned     2  MRHDRZER               field of zeros
      4   4  Unsigned     1  MRHDRDM                domain identifier
      5   5  Unsigned     1  *
      6   6  Unsigned     2  MRHDRRC                record identifier
      8   8  Character    8  MRHDRTOD               Time at which this record was
                                                    built. In time-of-day (TOD)
                                                    clock format. See IBM System
                                                    370 XA Principle of Operation
                                                    for explanation of format.
     16  10  Character    4  *
     20  14  Character    0  MRHDR_END              End of header
     20  14  Unsigned     4  SEKSEK_RDEVSID         Host subchannel I.D. number
                                                    defined at initialization
     24  18  Unsigned     2  SEKSEK_CALCURCY        Last seek cylinder for
                                                    previous DASD channel program
                                                    executed. RDEVCYL
     26  1A  Unsigned     2  SEKSEK_CALSKCYL        First cylinder requested in
                                                    seek command(s) in this real
                                                    channel program. IORCYL
     28  1C  Unsigned     2  SEKSEK_CALSKHD         First head number requested
                                                    in seek command(s) in this real
                                                    channel program. IORHEAD
     30  1E  Bitstring    1  SEKSEK_CALFLAGS        Flag byte
              1... ....      SEKSEK_IORDWRIT        ON=This is a WRITE channel
                                                    program. OFF=This is a READ
                                                    channel program.
              .1.. ....      *
              ..1. ....      *
              ...1 ....      *
              .... 1...      *
              .... .1..      *
              .... ..1.      *
              .... ...1      *
     31  1F  Bitstring    1  *                      Reserved for IBM use
     32  20  Character    8  SEKSEK_VMDUSER         Userid of requestor of seek
                                                    command(s) in this real channel
                                                    program. If 'SYSTEM', CP is the
                                                    requestor.
     40  28  Unsigned     4  SEKSEK_IORPOSCT        Number of DASD access arm
                                                    position changes within this
                                                    real channel program.
     44  2C  Unsigned     4  SEKSEK_IORPOSSM        Amount of access arm
                                                    movements (displacements).
                                                    Cumulative total of absolute
                                                    differences, in cylinders,
                                                    between successive seek
                                                    operation within this real
                                                    channel program
     48  30  Unsigned     2  SEKSEK_CALECYL         Final cylinder number
                                                    (position after this real
                                                    channel program completes).
                                                    IORECYL
     50  32  Unsigned     2  SEKSEK_VDEVDEV         Virtual device number of the
                                                    target device. Not applicable
                                                    if CP is the requestor (i.e.,
                                                    SEKSEK_VMDUSER = 'SYSTEM').
     52  34  Character    8  SEKSEK_CALUSER         Userid of the owner of the
                                                    target device. Not applicable
                                                    if CP is the requestor (i.e.,
                                                    SEKSEK_VMDUSER = 'SYSTEM').
     60  3C  Unsigned     2  SEKSEK_RDEVDEV         Device number
     62  3E  Unsigned     2  *                      Reserved and available for
                                                    IBM use.
     64  40  Character    0  SEKSEK_END

    MRSEKSEK Cross Reference

                          Hex           Hex
    Name                 Offset Length Value

    MRHDR                      0     20
    MRHDR_END                 14      0
    MRHDRDM                    4      1
    MRHDRLEN                   0      2
    MRHDRRC                    6      2
    MRHDRTOD                   8      8
    MRHDRZER                   2      2
    SEKSEK                     0     64
    SEKSEK_CALCURCY           18      2
    SEKSEK_CALECYL            30      2
    SEKSEK_CALFLAGS           1E      1
    SEKSEK_CALSKCYL           1A      2
    SEKSEK_CALSKHD            1C      2
    SEKSEK_CALUSER            34      8
    SEKSEK_END                40      0
    SEKSEK_IORDWRIT           1E           80
    SEKSEK_IORPOSCT           28      4
    SEKSEK_IORPOSSM           2C      4
    SEKSEK_MRHDR               0      0
    SEKSEK_RDEVDEV            3C      2
    SEKSEK_RDEVSID            14      4
    SEKSEK_VDEVDEV            32      2
    SEKSEK_VMDUSER            20      8

    This information is
    based on z/VM V5R2.0.

    Last updated on 11 Dec 2005 at 18:48:12.

    Copyright IBM Corporation, 1990, 2005