Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!decwrl!shelby!polya!rokicki
From: rokicki@polya.Stanford.EDU (Tomas G. Rokicki)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Virtual Memory
Message-ID: <9142@polya.Stanford.EDU>
Date: 12 May 89 17:17:28 GMT
References: <9140@polya.Stanford.EDU>
Sender: Tomas G. Rokicki <rokicki@polya.Stanford.EDU>
Organization: Stanford University
Lines: 17

I write:
> Page faulting during Forbid()/Permit() might be acceptable, if the
> page fault handler doesn't modify any standard system structures, just

Damn, what was I thinking?  To do disk I/O, you'd need to modify lots
of system structures, and even possibly put up error requestors and
the like.  (Unix machines *die* during swap errors---never thought
much about it before.)  But the changes may well be minimal---it would
be interesting to try.

In the meantime, I think we all had better be damned careful about
where and how we use Forbid()/Permit() and Enable()/Disable().

I really think this could be hacked up in a week, if someone was willing
to spend the time.  (You'd have to know the MMU somewhat.)

-tom