Article View: comp.arch
Article #22305Re: Multics & Memory mapped files
From: Wm E Davidsen Jr
Date: Fri, 09 Feb 1990 18:33
Date: Fri, 09 Feb 1990 18:33
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1583 bytes
In article <5180@crdgw1.crd.ge.com> hammondr@sunroof.crd.ge.com (Richard A Hammond) writes:
| Everybody seems to be missing the crucial fact about memory mapped files!
|
| They ONLY work for cases where the file size is < virtual address space!!!
|
| They are not a a generally useful solution which works over all possible
| implementations. UNIX file I/O does work over all situations!
You're right, but in general it doesn't matter. I looked over files on
about 200 Suns for large files, and the largest single file was under
100MB. Therefore for most applications there isn't a problem.
I'm not disagreeing that a problem is not impossible, but it's really
uncommon. You have to support really large text and database files, but
the average application never get a large file by 32 bit standards.
--
bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"Stupidity, like virtue, is its own reward" -me
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!crdgw1!crdos1!davidsen From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) Newsgroups: comp.arch Subject: Re: Multics & Memory mapped files Message-ID: <2115@crdos1.crd.ge.COM> Date: 9 Feb 90 18:33:18 GMT References: <8859@portia.Stanford.EDU> <20571@watdragon.waterloo.edu> <49956@sgi.sgi.com> <4791@helios.ee.lbl.gov> <2093@crdos1.crd.ge.COM> <1990Feb7.221800.804@utzoo.uucp> <2106@crdos1.crd.ge.COM> <5180@crdgw1.crd.ge.com> Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen) Organization: GE Corp R&D Center, Schenectady NY Lines: 18