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From: John Dyson <dyson>
Message-Id: <199512170434.UAA21780@freefall.freebsd.org>
Subject: Re: Is the Linux emulator not working for you?
To: terry@lambert.org (Terry Lambert)
Date: Sat, 16 Dec 1995 20:34:40 -0800 (PST)
Cc: peter@jhome.DIALix.COM, winter@jurai.net, kato@eclogite.eps.nagoya-u.ac.jp,
        current@FreeBSD.ORG
In-Reply-To: <199512170003.RAA08507@phaeton.artisoft.com> from "Terry Lambert" at Dec 16, 95 05:03:05 pm
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> 
> > I have been evaluating the possibility of the VM system properly
> > supporting ill constructed a.out formats (like those with 1K offset)
> > and it would not be too hard.  It would break coherency -- but
> > would add maybe 25-50 lines of code (very simple.)  Since it is
> > bad (not allowed) to modify a running binary anyway, the cost (in
> > functionality) is low.  I definitely plan to add it for 2.2.  But
> > if someone has a better (easier) solution -- PLEASE go for it!!!
> 
> You should talk to Matt Day (mday@elbereth.org).  He has been working
> on VOP_GETPAGE/VOP_PUTPAGE style linear address caching modification
> (ala SunOS/SVR4) if you think this will completely torpedo coherency.
> 
> You would have to get the details from him; he was talking about
> rolling the changes back in.
> 
I think that the SVR4 approach is not very good -- I hope he isn't 
planning on faulting into kernel space either.  There are some significant
re-dos happening in FreeBSD right now -- and the relationship of buffers and
I/O is in flux.  But -- I definitely do not want to shoot down anything that
might be good ....  Ask him to get into contact with me so that we can
coordinate the efforts.  (Hopefully he isn't trying to do exactly what SVR4
does :-)).

John
dyson@freebsd.org