Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!snorkelwacker!spdcc!esegue!johnl From: johnl@esegue.segue.boston.ma.us (John R. Levine) Newsgroups: comp.arch Subject: Re: the Multics from the black lagoon :-) Summary: file mapping soon to be in all unices Message-ID: <1990Feb9.044437.1415@esegue.segue.boston.ma.us> Date: 9 Feb 90 04:44:37 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> <5672@blake.acs.washington.edu> Reply-To: johnl@esegue.segue.boston.ma.us (John R. Levine) Followup-To: comp.unix.questions Organization: Segue Software, Cambridge MA Lines: 18 In article Keith Bierman writes: >In article <5672@blake.acs.washington.edu> Mark Crispin writes: > Now, I may accept the claim that file/memory mapping will be less > useful on Unix, because it won't be standard on every Unix system (and >It is part of the published feature list for V.4. So it will at least >be on all UI derived platforms, and one strongly suspects that this is >a feature that OSF will have no choice but to offer. We put it into AIX some years ago. I'm not sure the interface is the same; in AIX it's a funny kind of shmat() but the semantics are quite obvious. It was in response to requests from data base types who found it to be useful for implementing multiple simultaneous data base users, since it gets rid of a whole layer of buffering and hence synchronization problems. AIX also lets you map a file copy-on-write and then commit the changes back atomically. -- John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 864 9650 johnl@esegue.segue.boston.ma.us, {ima|lotus|spdcc}!esegue!johnl "Now, we are all jelly doughnuts."