*BSD News Article 5061


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Newsgroups: comp.unix.bsd
Path: sserve!manuel!munnari.oz.au!uunet!mcsun!sun4nl!fwi.uva.nl!casper
From: casper@fwi.uva.nl (Casper H.S. Dik)
Subject: Re: Shared Libs for X11?, was Re: 386bsd -- The New Newsgroup
Message-ID: <1992Sep15.150139.15216@fwi.uva.nl>
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References: <18iprpINNg6e@agate.berkeley.edu> <1992Sep8.200625.2894@socrates.umd.edu> 	<veit.716026274@du9ds3> <18lkkkINN14d@agate.berkeley.edu> 	<veit.716107923@du9ds3> <7dnL02y821gh01@JUTS.ccc.amdahl.com> 	<veit.716291291@du9ds3> <1992Sep14.232949.9093@bby.com.au> <veit.716561866@du9ds3>
Date: Tue, 15 Sep 1992 15:01:39 GMT
Lines: 35

veit@du9ds3.uni-duisburg.de (Holger Veit) writes:

>This is what I originally intended; I'm just sitting in front of a Sparc,
>and curiously watch what it is doing...:-). There are two possible problems:
>1. What will Sun say about using (or reverse-engineering) their solution
>   (in the light of AT&T vs. BSDI/UCB...)?

There is no reverse engeneering involved in AT&T vs BSDI/UCB. For one,
BSD had access to AT&T source code. I haven't heard Sun complaining
about anyone using/reimplementing the things they created.

>2. It is rumoured that the whole Sun DL stuff depends on or contains 
>   self-modifying code, which caused/s problems with SunOS look-alikes 
>   like Solbourne OS/MP (was fixed by some strange patch in OS/MP). I don't
>   know whether this is needed (I suppose, not), but it make me think that
>   this can be not a clean solution.

All dynamic linkiung will probably have some sort of ``self modifying code''
problem. The dynamic linker will have to patch the code somewhat.

If there was a problem on Solbournes that didn't exist on Suns than
that can be easily explained.  The SPARC based machines shipped by Sun
all had a unified I&D cache (The SS10 changes that, however).
Solbournes ships machines with a split I&D cache. This gives some
problems if you code. The solution is simple, flush the cache after
you're done with linking.

There are a number of problems with the shared library implementation in
SunOS 4.x. Although the construction of shared libraries seems easy enough,
breaking the rules isn't easily detected and costs a fortune in VM.

Casper
-- 
						|	Casper H.S. Dik
						|	casper@fwi.uva.nl