CLARIFICATION
There seems to have been a great deal of confusion over what this
benchmark measures, and how to use these results.  Let me try to clarify
this:

	1) DHRYSTONE is a measure of processor+compiler efficiency in
	   executing a 'typical' program.  The 'typical' program was
	   designed by measuring statistics on a great number of
	   'real' programs.  The 'typical' program was then written
	   by Reinhold P. Weicker using these statistics.  The
	   program is balanced according to statement type, as well
	   as data type.

	2) DHRYSTONE does not use floating point.  Typical programs don't.

	3) DHRYSTONE does not do I/O.  Typical programs do, but then
	   we'd have a whole can of worms opened up.

	4) DHRYSTONE does not contain much code that can be optimized
	   by vector processors.  That is why a CRAY doesn't look real
	   fast, they weren't built to do this sort of computing.

	5) DHRYSTONE does not measure OS performance, as it avoids
	   calling the O.S.  The O.S. is indicated in the results only
	   to help in identifying the compiler technology.

	6) DHRYSTONE is not perfect, but is a hell of a lot better than
	   the "sieve", or "SI".

	7) DHRYSTONE gives results in dhrystones/second.  Bigger
	   numbers are better.  As a baseline, the original IBM PC
	   gives around 300-400 dhrystones/second with a good compiler.
	   The fastest machines today are approaching 100,000.

If somebody asked me to pick out the best machine for the money, I
wouldn't look at just the results of DHRYSTONE.  I'd probably:

	1) Run DHRYSTONE to get a feel for the compiler+processor
	   speed.
	2) Run any number of benchmarks to check disk I/O bandwidth,
	   using both sequential and random read/writes.
	3) Run a multitasking benchmark to check multi-user response
	   time.  Typically, these benchmarks run several types of
	   programs such as editors, shell scripts, sorts, compiles,
	   and plot the results against the number of simulated users.
	4) If appropriate for the intended use, run something like
	   WHETSTONE, to determine floating point performance.
	5) If appropriate for intended use, run some programs which do
	   vector and matrix computations.
	6) Figure out what the box will:
		- cost to buy
		- cost to operate and maintain
		- be worth when it is sold
		- be worth if the manufacturer goes out of business
	7) Having done the above, I probably have a hand-full of
	   machines which meet my price/performance requirements.
	   Now, I find out if the applications programs I'd like
	   to use will run on any of these machines.  I also find
	   out how much interest people have in writing new software
	   for the machine, and look carefully at the migration path
	   I will have to take when I reach the (inevitable) limits
	   of the machine.

To summarize, DHRYSTONES by themselves are not anything more than
a way to win free beers when arguing 'Box-A versus Box-B' religion.
They do provide insight into Box-A/Compiler-A versus Box-A/Compiler-B
comparisons.

			Rick Richardson
			PC Research, Inc.
			(201) 389-8963 (9-17 EST)
			(201) 542-3734 (7-9,17-24 EST)
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