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

#### MRSTOASS

Prolog
Control Block Contents
Cross Reference

#### MRSTOASS Prolog

     DSECT NAME - STOASS
     FUNCTION - Map a Monitor record.
     LOCATED BY -
            Through the Monitor Control Area
     REFERENCED CONTROL BLOCKS -
            MRRECHDR    Monitor Record Header
     NAME - MRSTOASS
     DESCRIPTIVE NAME - Monitor Sample Record
                        Domain 3 - Storage Domain
                        Record 11 - Auxiliary Shared Storage Management
                                   (per Exposure)
     DESCRIPTION - Describes shared device space usage.  A separate
                   record is generated for each hardware exposure
                   associated with each CP-owned shared volume.
                   Note: This record will not contain paging and
                   spooling allocation.  This information is recorded
                   only on the system owning the device.

#### MRSTOASS Control Block Contents

    Offsets
    Dec  Hex  Type        Len  Name (Dim)             Description

       0   0  Structure   120  STOASS                 Start of monitor record
       0   0  Character     0  STOASS_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  Character     6  STOASS_CPVOLSER        VOLUME serial identifier
      26  1A  Character     2  *                      Reserved for IBM use
      28  1C  Unsigned      4  STOASS_RDEVSID         host subchannel I.D. number
                                                      defined at initialization
      32  20  Unsigned      4  STOASS_EXPCTSRD        Total number of pages read
                                                      from spool.
      36  24  Unsigned      4  STOASS_EXPCTSWR        Total number of pages
                                                      written to spool.
      40  28  Unsigned      4  STOASS_EXPCTPRD        Total number of (non-spool)
                                                      pages read from this device.
                                                      Note that page read
                                                      operations may be directed to
                                                      devices without any cylinders
                                                      specifically defined as type
                                                      PAGE.
      44  2C  Unsigned      4  STOASS_EXPCTPWR        Total number of (non-spool)
                                                      pages written to this device.
                                                      Note that page write
                                                      operations may be directed to
                                                      devices without any cylinders
                                                      specifically defined as type
                                                      PAGE.
      48  30  Unsigned      4  STOASS_EXPCURQC        The number of page/spool
                                                      read/writes that are
                                                      currently active or queued on
                                                      this logical device
      52  34  Character     4  *                      Reserved for IBM use.
                                                      Previous field is no longer
                                                      meaningful. (STOASS_EXPCTACP)
      56  38  Unsigned      4  STOASS_EXPCTUSI        Number of times user I/O
                                                      interferes with paging and
                                                      spooling I/O.
      60  3C  Unsigned      2  STOASS_SCMSSCH         Cumulative count of SSCH
                                                      and RSCH for this device.
                                                      This value may be wrapped
                                                      when format-1 measurement
                                                      blocks are being used
                                                      (MTRSYS_CALFLG2 <> x'80').
      62  3E  Unsigned      2  *                      Reserved for IBM use
      64  40  Unsigned      4  STOASS_SCGSSCH         Fullword cumulative count
                                                      of SSCH and RSCH for this
                                                      device. Available when
                                                      format-1 measurement blocks
                                                      are being used
                                                      (MTRSYS_CALFLG2 = x'80').
      68  44  Unsigned      2  STOASS_RDEVDEV         Device number
      70  46  Unsigned      2  *                      Reserved and available for
                                                      IBM use.
      72  48  Unsigned      1  STOASS_PHDTYPEF        I/O protocol flags
              1... ....        STOASS_PHDHXPBK         The exposure block for
                                                      this device is an HXPBK. When
                                                      this bit is ON, the paging
                                                      subsystem exploits HyperPAV
                                                      and HPF when those features
                                                      are enabled and supported by
                                                      the device. When this bit is
                                                      OFF, the exposure block is an
                                                      EXPBK.
              .1.. ....        STOASS_PHDECKD          ECKD paging volume.
              ..1. ....        STOASS_PHDSCSI          SCSI paging volume.
              ...1 ....        STOASS_PHDFBA           FBA paging volume.
              .... 1...        *
              .... .1..        *
              .... ..1.        *
              .... ...1        *
      73  49  Unsigned      3  *                      Reserved for IBM use.
      76  4C  Unsigned      4  STOASS_CALCURQS        Current number of pages
                                                      queued on the paging exposure
                                                      block originating from either
                                                      a single-page read or a
                                                      single-page write request.
      80  50  Unsigned      4  STOASS_CALCURQMW       Current number of pages
                                                      queued on the paging exposure
                                                      block originating from a
                                                      multi-page write request.
      84  54  Unsigned      4  STOASS_CALCURQMR       Current number of pages
                                                      queued on the paging exposure
                                                      block originating from a
                                                      multi-page read request.
      88  58  Unsigned      4  STOASS_HXPIORAC        Current number of paging
                                                      subsystem IORBKs handed off
                                                      to the I/O subsystem. This
                                                      includes IORBKs active on the
                                                      base and aliases, and any
                                                      queued off the RDEV of the
                                                      base.
      92  5C  Unsigned      4  STOASS_HXPPAIOC        Cumulative count of times
                                                      the paging subsystem's
                                                      channel program build routine
                                                      (HCPPAIIO) was stacked.
      96  60  Unsigned      4  STOASS_CALSSCHAL       Cumulative count of SSCHs
                                                      issued on HyperPAV alias
                                                      devices for this base device.
     100  64  Unsigned      1  STOASS_HXPFLAGC        Capability flags.
              1... ....        STOASS_HXPHPAV          The last I/O to this
                                                      volume requested alias use.
                                                      HyperPAV is enabled and the
                                                      device is a HyperPAV base.
                                                      The I/O subsystem will
                                                      determine if the I/O is
                                                      executed via an alias.
              .1.. ....        STOASS_HXPHPF           The last I/O to this
                                                      volume was a transport mode
                                                      channel program. HPF is
                                                      enabled and the device is HPF
                                                      capable.
              ..1. ....        STOASS_HXPFCMD          The last I/O to this
                                                      volume was a command mode
                                                      channel program because it
                                                      was directed to a mapped
                                                      minidisk or was a retry from
                                                      an HPF error.
              ...1 ....        *
              .... 1...        *
              .... .1..        *
              .... ..1.        *
              .... ...1        *
     101  65  Unsigned      1  STOASS_HXPNOHPF        HPF failure flags. Usage of
                                                      HPF has been suspended.
              1... ....        STOASS_HXPNPROG         An error other than
                                                      missing HPF feature has
                                                      occurred.
              .1.. ....        STOASS_HXPNFEAT         An HPF feature is no
                                                      longer available.
              ..1. ....        *
              ...1 ....        *
              .... 1...        *
              .... .1..        *
              .... ..1.        *
              .... ...1        *
     102  66  Unsigned      1  STOASS_HXPRTYFT        Retry count for HPF feature
                                                      lost.
     103  67  Unsigned      1  STOASS_HXPRTYOT        Retry count for failure
                                                      other than HPF feature lost.
     104  68  Unsigned      4  STOASS_PHDSSCHR        Cumulative count of SSCHs
                                                      (and RSCHs when
                                                      STOASP_PHDHXPBK is OFF) for
                                                      read.
     108  6C  Unsigned      4  STOASS_PHDSSCHW        Cumulative count of SSCHs
                                                      (and RSCHs when
                                                      STOASP_PHDHXPBK is OFF) for
                                                      write.
     112  70  Unsigned      4  STOASS_PHDLOCRR        Cumulative count of Locate
                                                      Record operations for read
                                                      (includes the initial search
                                                      even when the information is
                                                      provided by a Prefix CCW).
     116  74  Unsigned      4  STOASS_PHDLOCRW        Cumulative count of Locate
                                                      Record operations for write
                                                      (includes the initial search
                                                      even when the information is
                                                      provided by a Prefix CCW).
     120  78  Character     0  STOASS_END

#### MRSTOASS 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
    STOASS                     0    120
    STOASS_CALCURQMR          54      4
    STOASS_CALCURQMW          50      4
    STOASS_CALCURQS           4C      4
    STOASS_CALSSCHAL          60      4
    STOASS_CPVOLSER           14      6
    STOASS_END                78      0
    STOASS_EXPCTPRD           28      4
    STOASS_EXPCTPWR           2C      4
    STOASS_EXPCTSRD           20      4
    STOASS_EXPCTSWR           24      4
    STOASS_EXPCTUSI           38      4
    STOASS_EXPCURQC           30      4
    STOASS_HXPFCMD            64           20
    STOASS_HXPFLAGC           64      1
    STOASS_HXPHPAV            64           80
    STOASS_HXPHPF             64           40
    STOASS_HXPIORAC           58      4
    STOASS_HXPNFEAT           65           40
    STOASS_HXPNOHPF           65      1
    STOASS_HXPNPROG           65           80
    STOASS_HXPPAIOC           5C      4
    STOASS_HXPRTYFT           66      1
    STOASS_HXPRTYOT           67      1
    STOASS_MRHDR               0      0
    STOASS_PHDECKD            48           40
    STOASS_PHDFBA             48           10
    STOASS_PHDHXPBK           48           80
    STOASS_PHDLOCRR           70      4
    STOASS_PHDLOCRW           74      4
    STOASS_PHDSCSI            48           20
    STOASS_PHDSSCHR           68      4
    STOASS_PHDSSCHW           6C      4
    STOASS_PHDTYPEF           48      1
    STOASS_RDEVDEV            44      2
    STOASS_RDEVSID            1C      4
    STOASS_SCGSSCH            40      4
    STOASS_SCMSSCH            3C      2

    This information is
    based on z/VM V7R2.0.

    Last updated on 08 August 2020 at 21:31:09.

    Copyright IBM Corporation, 1990, 2020