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From: xxremak@csduts1.lerc.nasa.gov (David A. Remaklus)
Newsgroups: comp.arch
Subject: Re: Centralized vs distributed computing
Message-ID: <1990Mar21.142014.20419@eagle.lerc.nasa.gov>
Date: 21 Mar 90 14:20:14 GMT
References: <9003210649.AA06750@jade.berkeley.edu>
Reply-To: xxremak@csduts1.lerc.nasa.gov (David A. Remaklus)
Organization: NASA/Lewis Research Center, Cleveland
Lines: 44

In article <9003210649.AA06750@jade.berkeley.edu> C506634@UMCVMB.MISSOURI.EDU ("Eric Edwards") writes:
>Large, shared, systems seem to be good for
>1) large, compute intensive tasks
>2) large, IO intensive tasks
>3) tasks in which data must be shared with other users.
>And are poor at
>1) User interaction
>2) small jobs that need to have a predictable completion time.
>
>Wheras, single user systems excel at the second group and come up short on the
>first.  So.....  Why not combine the two.
>

Checkout TCF (Transparent Computing Facility) proposed by IBM for the
AIX platforms.  While I don't have the specifics myself, they seem to
have created a "seamless" path from the PS/2 through the 3090.
Essentially, they create shadowed files where multiple execution images
appear under the same name.  To illustrate, consider the program /bin/sh.
With TCF, there is a common NFS like file system between the various
platforms (PS/2, RT, RS600, 3090, etc).  Through a normal directory
list, a user would only see a single /bin/sh, when actually there could
be an executable for each.  Which ever platform you were running on is the
executable chosen.

The really neat feature is the case where an executable does
not exist for your platform.  In that case, an executable for a different
platform is chosen and automatically executed there without you having
logged into the machine.  This is best seen in the case of a.out files
where you may be logged into a PS/2 where you edit, compile and link,
but what you created was perhaps a 3090 executable.  When you run it,
it executes on the 3090 without your being aware that it did.

IBM did a song and dance on this thing at a recent SHARE meeting that
I think was last year (89).  The presentation material ought to be in
the proceedings.  The really sad thing is, that true to form, IBM doesn't
appear willing to release the specs for TCF into the public domain.  Its
a real shame as I have never seen anything like it since.

Dave R.
--
David A. Remaklus
NASA Lewis Research Center
Cleveland, Ohio
xxremak@csduts1.lerc.nasa.gov