From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,ce6f6f23c4e880ad X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-06-24 08:19:17 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!paloalto-snf1.gtei.net!crtntx1-snh1.gtei.net!chcgil2-snf1.gtei.net!news.gtei.net!news.binc.net!kilgallen From: Kilgallen@SpamCop.net (Larry Kilgallen) Newsgroups: comp.lang.ada Subject: Re: Multitasking theory question Date: 24 Jun 2002 10:19:15 -0600 Organization: LJK Software Message-ID: References: <3d123f34.0@news.unibw-muenchen.de> <3D128BA9.8090707@telepath.com> <3D16B14B.2A5D8261@attbi.com> <3D173788.8758A005@san.rr.com> NNTP-Posting-Host: eisner.encompasserve.org X-Trace: grandcanyon.binc.net 1024931936 6987 192.135.80.34 (24 Jun 2002 15:18:56 GMT) X-Complaints-To: abuse@binc.net NNTP-Posting-Date: Mon, 24 Jun 2002 15:18:56 +0000 (UTC) Xref: archiver1.google.com comp.lang.ada:26657 Date: 2002-06-24T10:19:15-06:00 List-Id: In article <3D173788.8758A005@san.rr.com>, Darren New writes: > AG wrote: >> However, what I was driving at is a sort of a virtual machine: >> - *assuming* it runs at all, and lets you do some basic things >> like Turing machine, where does an OS come into it? > > The places where a machine isn't a turing machine. I.e., Input/Output. > >> Sure, it >> may take ages for anything to happen if the computer is sufficiently >> slow but you still can implement whatever scheduling you like. > > Uh, no. If you have a 3rd party device driver that blocks, then you can't do > non-blocking I/O to that device, regardless of what cleverness you set up in > your part of the program. In that case, you should switch to an operating system that does not allow device drivers to block.