From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <007d01c1ae4d$9e0c3700$0365c0d0@cc583254b>
From: "david presotto" <presotto@closedmind.org>
To: <9fans@cse.psu.edu>
References: <20020205105739.AF44019999@mail.cse.psu.edu>
Subject: Re: [9fans] Virtual memory & paging
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Date: Tue,  5 Feb 2002 09:01:31 -0500
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Actually, I'ld be seriously worried about our ability to
add DLL support without major bugs.  It adds a lot
of complexity that spans the VM model, security,
and compilers.  A lot of Plan 9's speed and usefulness
arises from its simplicity and this would be a major step in
away from that, not that we haven't been whores 
before.

A major drawback right now is that, unless we change
our MMU handling in a drastic way,
we have to run the shared library at the same addresses
in all programs.   Might be a bit of a problem (unless we
go to 64 bit addressing).  The current MMU
model with its lazy evaluation and no need for a
intermachine shootdown is quite elegant and I'm not sanguine
to lose it just for DLL's.

As Geoff states, we don't seem to be losing out by not
having them, vis a vis memory size.  Some things would
be more efficiently done with a shared library, shared
databases for example.  I'm just not yet prepared to
pay the price in increased complexity.  Others may be.