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From: mat@hou5e.UUCP (M Terribile)
Newsgroups: net.unix-wizards
Subject: Re: Shared system routines
Message-ID: <680@hou5e.UUCP>
Date: Wed, 27-Jul-83 10:19:48 EDT
Article-I.D.: hou5e.680
Posted: Wed Jul 27 10:19:48 1983
Date-Received: Wed, 27-Jul-83 21:54:25 EDT
References: <505@mit-eddie.UUCP>
Organization: American Bell ED&D, Holmdel, NJ
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There is one reason for not putting a shared library system on an OS.
It is vary hard to do it in a way that is both general and right without
sacrificing machine cycles, IO bandwidth, or something else.

I have seen it done efficiently, but in a very specific way, to help
maintain speed of a UNI*X machine dedicated to a few special applications.
I have seen it done generally, on the HP 3000, with HARDWARE SUPPORT.  As
a result, loading the COBOL compiler can take up over 3 seconds of dedicated
disk usage (run-time linking).  It IS possible to get around it; the HP's
OS has a ``sticky-bit'' type of facility; but the problem affects EVERYTHING
that runs on the machine and the difference between a dog of a machine and
a smooth--running one lies almost entirely in the technical savvy of the
system administrators.  Not desireable!

Perhaps a middle ground could be found in a multi-kernelized system, with
an efficient ``sys call'' facility, but if you are talking about cheap
machines (managers DO buy DG machines, you know) it may take a while
to happen.

						Mark Terribile
						Duke of deNet