Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!cbatt!ucbvax!sdcsvax!darrell
From: darrell@sdcsvax.UUCP
Newsgroups: mod.os
Subject: Re: Experiences with RPC
Message-ID: <2601@sdcsvax.UCSD.EDU>
Date: Mon, 26-Jan-87 13:16:31 EST
Article-I.D.: sdcsvax.2601
Posted: Mon Jan 26 13:16:31 1987
Date-Received: Tue, 27-Jan-87 05:45:31 EST
Sender: darrell@sdcsvax.UCSD.EDU
Organization: NASA Ames Research Center, Mountain View, CA
Lines: 32
Approved: mod-os@sdcsvax.uucp

--

In our formal plans for the NAS supercomputer facility, we intended to use
the machine to global translation format, so as to only have to write 2n
translators, rather than 2^n; and in the long run we will probably have to
do that.

In the short run, we've found that machine specific translation was important
in our environment for the reason of asymetry of processing power.  While it
may take the Cray 2 tenths of seconds to translate a file of binary data to
or from the 'machine independent' format, it can take a 680xx based workstation
many hours to translate the same file.

For us, it makes sense to have a 2n translation facility on the Cray 2
consisting of translations to and from the local format of each of the
workstations.  Since n currently is equal to 1, there is no win or loss
as far as the amount of code for translators is concerned and there is
a big win as far as the amount of time spent translating.

I think this kind of pragmatism is still important in algorithm design.  In
this case, the small development time required for each new workstation is
more than compensated by the large gain in execution time.

In fact, a problem which could come to exist in the future is that of two
workstations with incompatable format using the supercomputer as a translation
service.  If the cost to copy the file to the supercomputer in A's local
format, have the supercomputer perform the two translations (A->supercomputer)
and (supercomputer->B) and then transfer the file to B is lower than the
cost of A translating to B and sending, A sending and B translating, etc
then users will use that; which leads to the idea of a translation server.

--