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From: guy%gorodish@Sun.COM (Guy Harris)
Newsgroups: comp.unix.wizards
Subject: Re: multiple-machine executables for Suns?
Message-ID: <24949@sun.uucp>
Date: Wed, 5-Aug-87 16:05:46 EDT
Article-I.D.: sun.24949
Posted: Wed Aug  5 16:05:46 1987
Date-Received: Sat, 8-Aug-87 05:27:44 EDT
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> Regarding Sun software distributions, I think that distributing binaries
> for only one machine type is perfectly suitable, but is that a reason for not
> having the capability to have multiple-machine executables?

Given the development effort required to make this work for all the
tools that deal with object files (and given that it gets more
complicated with something like the approach to shared libraries
described in the USENIX talk by Gingell *et al*), it may very well be
a reason for not having this capability.

Sun, like any other organization, has finite resources for doing
development; you have to choose where you're going to put your
resources.  It's not clear that the benefits *to Sun* of providing
this capability exceed the costs of doing so.

> Also, it seems that compiling a binary for N machines *is* simpler than
> compiling N binaries for N machines.  Consider:
> 
> 	cc -o /usr/local/newprog -Msun2 -Msun3 -Msun4 newprog.c
> 
> versus:
> 	cc -o /r/sun2/usr/local/newprog -Msun2 newprog.c
> 	cc -o /r/sun3/usr/local/newprog -Msun3 newprog.c
> 	cc -o /r/sun4/usr/local/newprog -Msun4 newprog.c

Not really much simpler; note that the three commands are identical
except for the "-M" flag (which wouldn't be used - "-M" already means
something to "cc") and the pathname of the target.  Compiling
binaries is usually done with "make", not "cc", so the difference
would be the difference between

	make newprog

and

	make CPU=sun2 newprog
	make CPU=sun3 newprog
	make CPU=sun4 newprog

> I also believe that Sun does not introduce incompatiblities to sell new
> machines, but incompatibility surely has an effect on sales.

Yes, but I suspect the major impact of the Sun-4's incompatibility
has nothing to do with the availability of multiple-machine binaries.
Most people who wouldn't buy a Sun-4 for compatibility reasons would
do so because it wouldn't run Sun-3 binaries *at all*, not because
you can't bundle Sun-3 and Sun-4 binaries into the same file.  The
only way to "fix" that would have been not to come out with the Sun-4
at all!
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com