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Article #2899Re: Reasons For Large Main Memories
From: joel
Date: Mon, 22 Sep 1986 22:19
Date: Mon, 22 Sep 1986 22:19
25 lines
1930 bytes
1930 bytes
>cheap, systems. If you don't need the benefits of virtual memory, you
>shouldn't be asked to pay its costs. Has anyone seen a multiprocessor scheme
>where some processors maintain physical spaces and others virtual? I'll
>--> Jon Krueger
I haven't seen it done on a processor basis, but I've seen it
done on a task by task basis. On our OS32MT operating most tasks
run in real memory, but you can specify a virtual task manange-
ment option at link time. All tasks run with address relocation
hardware enabled, while virtual tasks actually have routines
to handle page faults linked in. This means that the size of
the working set of the task is fixed at load time, rather
than sharing a common pool with other virtual tasks. There is
an additional problem in that the page size is a rather
unwieldy 64KB.
Also on MVS back on IBM mainframes there is a V=R where the
whole task is loaded into a contiguous chunk of real memory.
This was generally used with small tasks with critical
performance.
--
Joel Upchurch @ CONCURRENT Computer Corporation (A Perkin-Elmer Company)
Southern Development Center
2486 Sand Lake Road/ Orlando, Florida 32809/ (305)850-1031
{decvax!ucf-cs, ihnp4!pesnta, vax135!petsd, akgua!codas}!peora!joel
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!lll-crg!nike!ucbcad!ucbvax!decvax!decwrl!amdcad!amd!pesnta!peora!joel From: joel@peora.UUCP Newsgroups: net.arch Subject: Re: Reasons For Large Main Memories Message-ID: <2448@peora.UUCP> Date: Mon, 22-Sep-86 18:19:29 EDT Article-I.D.: peora.2448 Posted: Mon Sep 22 18:19:29 1986 Date-Received: Tue, 23-Sep-86 18:51:17 EDT References: <1161@bu-cs.bu-cs.BU.EDU> <8529@duke.duke.UUCP> <672@ur-tut.UUCP> <7418@lanl.ARPA> <684@ur-tut.UUCP> Organization: Concurrent Computer Corporation, Orlando, Fl Lines: 25 Keywords: virtual memory appropriate