Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!mailrus!ncar!boulder!atk
From: atk@boulder.Colorado.EDU (Alan T. Krantz)
Newsgroups: comp.arch
Subject: Re: Architectural Requirements for Unix (was: upgrades)
Message-ID: <21808@boulder.Colorado.EDU>
Date: 2 Jun 90 20:15:09 GMT
References: <2286@crdos1.crd.ge.COM> <29972@cup.portal.com> <1990May14.141148.9884@xavax.com> <7754@crdgw1.crd.ge.com> <30016@cup.portal.com> <1990May19.230618.16090@utzoo.uucp> <383@garth.UUCP> <1990Jun2.134157.14516@oracle.com>
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Reply-To: atk@boulder.Colorado.EDU (Alan T. Krantz)
Organization: University of Colorado, Boulder
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In article <1990Jun2.134157.14516@oracle.com> csimmons@oracle.com writes:
>In article <2286@crdos1.crd.ge.COM>, davidsen@crdos1.crd.ge.COM (Wm E
>Davidsen Jr) writes:
>> | 3) Using explicit sharing of library code
>> 
>>   This could be done with segments, although I don't know of any machine
>> which does it. I looked at doing it on a 286, with all the library
>> routines called with far calls to a library segment. I am sure it can be
>> done, but I don't have an example of doing it.
>> 
>
>Ah!  I can't pass this one up.  Turns out that one of your favorite
>machines, the GE 6something (well, one of its descendents), does this
>sort of thing.  The Dartmouth College Time Sharing system started
>putting shared libraries in segments in around 1985 or so.  Worked
>great.
>
>-- Chuck

I'm not sure what you mean by explicit sharing of library code - but tops-10
did this sort of things with segments. Every program had two segments - a
"high" segment for code (usually writeing was disabled) and a low segment for
data. What the fortran compiler did was put the user's code in the low segment
and then when the program ran it specified the name of the "shared" hi segment
which contained the fortran library (a user could force the linker to generate
his own copy of the fortran library. Of course - one day our machine had a 
parity error - just so happen it was in the middle of the shared segment - so
all the fortran programs died... 

One neat part of using the shared segments was that the run library could be
updated without rebuilding the user's programs ...

Oh - I wish someone would donate a PDP-10 to me - and a house with a powerplant
to run it ...


 
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