[VAX83D.USS.USS]AAAREADME.TXT

	USS.MAR contains an example of a user written system service.
This service accesses the hardware clock registers to obtain
microsecond timing statistics.  TEST.FOR contains an example of
how to use it.

	USS.MAR is based on the USSDISP routines in [SYSHLP.EXAMPLES].
Note that a similar capability was required by Richard Kayfes in order
to write his excellent paper "VAX/VMS Real Timer Performance Test
Results" which appeared in the May 1983 Pageswapper.

	Readers will note the possibility of modifying the NICR
register (as was reported in a Magic Session 2 years ago).  A little
over 30 minutes of "dedicated" execution could be run before updating
the software time (and the time update routine in VMS could be modified).
This does have effects on scheduling, etc., but programs to do that have 
been written, and the system continued to run in timesharing mode.
I mention this as a possibility, not necessarily recommended, and with
no acceptance of responsibility for implementations outside my shop.

	Mark C. Paulk
	System Development Corporation
	Huntsville, AL  35805