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

#### HFOBK

Prolog

Control Block Contents
HFOBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### HFOBK Prolog

     NAME       : HCPHFOBK
     DESCRIPTION: Monitor I/O Domain Hi-Frequency Sample Data Area
     DSECT      : HFOBK
     FUNCTION   : Control block for I/O-domain high-frequency
                  sample data.  There is a separate HCPHFOBK for
                  each I/O device that is being sampled. Data collected
                  here are later transferred to the I/O domain monitor
                  record, MRIODDEV.
     LOCATED BY : RDEVHFSD
     CREATED BY : HCPMOOIN
     DELETED BY : HCPMOOTM
     REFERENCES : none
     SERIALIZED : RDEVHFLK lockword in the I/O device's respective RDEV
     NOTES      : none

#### HFOBK Control Block Content

#### HFOBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      HFOBK          Monitor I/O Domain Hi-Frequency
                                            Sample Data Area
    0000    0 Signed       4 HFOCOUNT       Number of samples
    0004    4 Signed       4 HFOCNTIO       Number of queued SSCH requests,
                                            excluding the active requests
                                            from field RDEVCTIO
              00000008       HFO$END        * End of HFOBK
              00000001       HFOSIZE        (HFO$END-HFOBK+7)/8 HFOBK size in
                                            doublewords

#### HFOBK Storage Layout

    *** HFOBK - Monitor I/O Domain Hi-Frequency Sample Data Area
    *
    *     +---------------------------+---------------------------+
    *   0 |         HFOCOUNT          |         HFOCNTIO          |
    *     +---------------------------+---------------------------+
    *   8
    *
    *** HFOBK - Monitor I/O Domain Hi-Frequency Sample Data Area

#### HFOBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    HFO$END        0004 00000008
    HFOCNTIO       0004
    HFOCOUNT       0000
    HFOSIZE        0004 00000001

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 16:58:22 EDT.
Copyright IBM Corporation, 1990, 2005