750 FPA Experiences Sought

[stuart at rochester.UUCP]

From: Stuart Friedberg  <stuart>
We have several 750's, one of which is used extensively for computer
vision research and VLSI design. A lot of these computations tend to
be heavy on the floating point. Does any one have concrete experience
with the floating point accelerator for the 750? Please mail me
responses and I will summarize for the net.

I would appreciate responses that address the following questions.

  1) What kind of program mix do you run? (Numeric codes, general
     timesharing, etc. Essentially, do you run a lot of floating point?)

  2) Does the 750 FPA provide significantly improved performance on
     floating point calculations? How much? Is this measurement or
     subjective (expert) judgement?

  3) Does the 750 FPA provide significantly improved performance on
     code which is not FP intensive? Do the (DEC) documented
     enhancements of integer division and the like actually show up?
     How much? Measurement or seat of the (expert) pants?

  4) What difficulties or joys does the process of installation bring?
     What else breaks? The DEC architecture book claims you can just
     plug one in and run, but there is a $400 installation fee. Why?

  5) Is maintenance/repair/infant mortality an issue? Can you ignore
     it after installation?

  6) Do you think the 750 FPA was cost effective for your application?
     Why (not)? Would you recommend the installation of a 750 FPA at a
     floating point intensive machine?

			Thanks in advance for your helpful replies,
				Stu Friedberg
			{seismo, allegra}!rochester!stuart
				stuart at rochester