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

#### MRIODCAD

Prolog
Control Block Contents
Cross Reference

#### MRIODCAD Prolog

     DSECT NAME - IODCAD
     FUNCTION - Map a Monitor record.
     LOCATED BY -
            Through the Monitor Control Area
     REFERENCED CONTROL BLOCKS -
            MRRECHDR    Monitor Record Header
     NAME - MRIODCAD
     DESCRIPTIVE NAME - Monitor Sample Record
                        Domain 6 - I/O Domain
                        Record 4 - Cache Activity Data
     DESCRIPTION - Records cache activities.  Generated for each device
                   that is attached to a caching control unit such as
                   a 3880 model 11, 13, 21, and 23, or a 3990 model 3.
                   Its purpose is to enable management of the paging
                   cache in the storage directors.
     NOTES:
      -- Data in IODCAD_CALDATA depends on the type of device being
         monitored.  The IODCAD_STATUS code indicates what kind of data
         is in it.
      -- For the 3880 Model 11, only the storage director that
         owns the cache is recorded.
      -- This record is not created for the secondary of a PPRC
         pair.
      -- This record is not created for PAV Alias devices
      -- This record is not created for HyperPAV Alias devices

#### MRIODCAD Control Block Contents

    Offsets
    Dec  Hex  Type        Len  Name (Dim)             Description

       0   0  Structure   316  IODCAD
       0   0  Character     0  IODCAD_MRHDR           Record header. See MRRECHDR
                                                      for details.
       0   0  Character    20  MRHDR
       0   0  Unsigned      2  MRHDRLEN
       2   2  Unsigned      2  MRHDRZER
       4   4  Unsigned      1  MRHDRDM
       5   5  Unsigned      1  *
       6   6  Unsigned      2  MRHDRRC
       8   8  Character     8  MRHDRTOD
      16  10  Character     4  *
      20  14  Character     0  MRHDR_END
      20  14  Unsigned      4  IODCAD_RDEVSID         host subchannel I.D. number
                                                      defined at initialization
      24  18  Signed        4  IODCAD_STATUS          code pertaining to contents
                                                      and mapping of the
                                                      IODCAD_CALDATA data area: -2
                                                      = No data because an I/O
                                                      request to obtain cache
                                                      information exceeded an
                                                      internal timer value and was
                                                      cancelled. -1 = No data
                                                      because the device is a
                                                      potential SIE ASSIST device.
                                                      0 = I/O Error in producing
                                                      the record. No data. 1 = data
                                                      from one storage director of
                                                      a 3880. Mapped by
                                                      IODCAD_CALDSSC. 2 = data from
                                                      both storage directors of a
                                                      3880. Mapped by
                                                      IODCAD_CALDSSC. 3 = data from
                                                      a 3990 model 3 or 6, a Shark,
                                                      a 9394, or a 9696 Mapped by
                                                      IODCAD_CALPSF.
      28  1C  Bitstring    40  IODCAD_CALSSS          Subsystem status, as
                                                      returned by the SENSE
                                                      SUBSYSTEM STATUS command.
                                                      Layout and contents, which
                                                      depend on the device, are
                                                      described in the device's
                                                      hardware manuals. If the
                                                      device returns more than 40
                                                      bytes of subsystem status,
                                                      field IODCAD_CALSSS2 contains
                                                      the additional status
      28  1C  Character     6  *                      Defined in device hardware
                                                      manuals (see above).
      34  22  Signed        2  IODCAD_PSFLEN          Length (in bytes) of
                                                      performance statistics which
                                                      are stored in IODCAD_CALPSF
                                                      for this device. If this
                                                      field is zero, then the
                                                      performance statistics length
                                                      is 96 bytes.
      36  24  Character    32  *                      Defined in device hardware
                                                      manuals (see above).
      68  44  Character   240  IODCAD_CALDATA         Data area. Contains status
                                                      and/or performance data. See
                                                      code in IODCAD_STATUS. Layout
                                                      and contents, which depend on
                                                      the device, are described in
                                                      the device's hardware
                                                      manuals.
     308 134  Bitstring     4  IODCAD_CALSSS2         Additional subsystem status
                                                      as returned by the SENSE
                                                      SUBSYSTEM STATUS command.
                                                      Layout and contents, which
                                                      depend on the device, are
                                                      described in the device's
                                                      hardware manuals.
     312 138  Unsigned      2  IODCAD_RDEVDEV         Real device address
     314 13A  Unsigned      2  *                      Reserved for IBM use
     316 13C  Character     0  IODCAD_END
    IODCAD_CALDSSC Status and performance data collected from a 3880 control
    unit. If IODCAD_STATUS = 1 data was collected only from the first
    storage director. IODCAD_CALSSC2 will not apply. If IODCAD_STATUS = 2
    data was collected from both storage directors.

    Offsets
    Dec  Hex  Type        Len  Name (Dim)             Description

       0   0  Structure   160  IODCAD_CALDSSC
       0   0  Bitstring    80  IODCAD_CALSSC1         Subsystem performance data,
                                                      as returned by the SENSE
                                                      SUBSYSTEM COUNTS command for
                                                      the first storage director
      80  50  Bitstring    80  IODCAD_CALSSC2         Subsystem performance data,
                                                      as returned by the SENSE
                                                      SUBSYSTEM COUNTS command for
                                                      the second storage director.
                                                      Applicable only when
                                                      IODCAD_STATUS = 2.
    IODCAD_CALPSF Status and performance data collected from a 3990 model 3
    or 6 a 9394 a 9696 or a Shark. Applicable only when IODCAD_STATUS = 3.

    Offsets
    Dec  Hex  Type        Len  Name (Dim)             Description

       0   0  Structure     0  *
       0   0  Character   240  IODCAD_CALPSF          Subsystem performance data,
                                                      as returned by the PERFORM
                                                      SUBSYSTEM FUNCTION, READ
                                                      SUBSYSTEM DATA (PERFORMANCE
                                                      STATISTICS) CCW chain

#### MRIODCAD Cross Reference

                          Hex           Hex
    Name                  Offset Length Value

    IODCAD                     0    316
    IODCAD_CALDATA            44    240
    IODCAD_CALDSSC             0    160
    IODCAD_CALPSF              0    240
    IODCAD_CALSSC1             0     80
    IODCAD_CALSSC2            50     80
    IODCAD_CALSSS             1C     40
    IODCAD_CALSSS2           134      4
    IODCAD_END               13C      0
    IODCAD_MRHDR               0      0
    IODCAD_PSFLEN             22      2
    IODCAD_RDEVDEV           138      2
    IODCAD_RDEVSID            14      4
    IODCAD_STATUS             18      4
    MRHDR                      0     20
    MRHDR_END                 14      0
    MRHDRDM                    4      1
    MRHDRLEN                   0      2
    MRHDRRC                    6      2
    MRHDRTOD                   8      8
    MRHDRZER                   2      2

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

    Last updated on 05 August 2020 at 20:37:56.

    Copyright IBM Corporation, 1990, 2020