Article View: comp.sys.amiga.tech
Article #2449Re: DMA in VM
From: Peter da Silva
Date: Fri, 01 Dec 1989 13:04
Date: Fri, 01 Dec 1989 13:04
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In article <14060@grebyn.com> ckp@grebyn.UUCP (Checkpoint Technologies) writes:
> Laugh if you like. In VAX/VMS, every part of a process is virtual
> memory, including any IO buffering. The IO system takes care of ensuring
> that such pages are resident and locked for the duration of a DMA IO
> transfer.
Too bad it doesn't go one step more and make the files *really* mapped, so
they "page" back into the real file they're supposed to come from.
Really, I don't see the point of writing stuff to one part of the disk when
you're just going to have to read it in again and write it to another part
of the disk later on.
This was a feature of Multics some, oh, 20 years ago now. ALL files were mapped
into memory... paged to and from the physical disk on demand.
--
Peter "Have you hugged your wolf today" da Silva <peter@sugar.hackercorp.com>
`-_-'
'U` "Really, a video game is nothing more than a Skinner box."
-- Peter Merel <pete@basser.oz>
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!texbell!sugar!peter From: peter@sugar.hackercorp.com (Peter da Silva) Newsgroups: comp.sys.amiga.tech Subject: Re: DMA in VM Message-ID: <4643@sugar.hackercorp.com> Date: 1 Dec 89 13:04:59 GMT References: <14059@grebyn.com> <2054@atanasoff.cs.iastate.edu> <14060@grebyn.com> Reply-To: peter@sugar.hackercorp.com (Peter da Silva) Organization: Sugar Land Unix - Houston Lines: 20