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Xref: sserve comp.os.386bsd.misc:3031 comp.os.linux.misc:21101 Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!constellation!news.uoknor.edu!ns1.nodak.edu!netnews.nwnet.net!reuter.cse.ogi.edu!psgrain!rainrgnews0!pacifier!news.alpha.net!MathWorks.Com!europa.eng.gtefsd.com!howland.reston.ans.net!EU.net!sunic!news.chalmers.se!cd.chalmers.se!tl From: tl@cd.chalmers.se (Torbj|rn Lindgren) Newsgroups: comp.os.386bsd.misc,comp.os.linux.misc Subject: Re: Usefulness of BSD/Linux Source Knowledge (was BSD vs. LINUX) Date: 4 Aug 1994 18:01:00 GMT Organization: Chalmers Computer Society Lines: 27 Message-ID: <31racs$si2@nyheter.chalmers.se> References: <30jqp1$ees@grex.cyberspace.org> <9407311523.08@rmkhome.com> <Ctv7KA.Jy9@news.cern.ch> <31mfon$efs@glitnir.ifi.uio.no> NNTP-Posting-Host: haddock.cd.chalmers.se In article <31mfon$efs@glitnir.ifi.uio.no>, Kjetil Torgrim Homme <kjetilho@ifi.uio.no> wrote: >+--- Dan Pop: >| When is SunOS 4.1.4 or 4.2.0 expected to be released? > >4.1.3 ought to be 4.2.0 -- the file system actually was incompatible >with 4.1.2... (if I understood my sysadmin correctly). Wrong. >A political decision has been made: 4.1.3 is the last version of SunOS >4. That's why the new versions are called 4.1.3U2 and so :-) [I'd >never think they'd begin putting in SMP in SunOS 4, but I guess their >customers force them to it.] Adding SMP was prrobably rather easy. Just put a big lock on the whole kernel... This means that only one process (or thread) can be in the kernel in the kernel a given time, but if that process can run on any processor you have a SMP (per definition, symmetric means that either processor may run kernel tasks, not that more than one process may be in the kernel). Creating a system where more than one process can be in the kernel at a give time is *much* harder, and SunOS 4.x doesn't support this (This is one of the major differences between SunOS 4 and Solaris 2). The main difference is that you have to use data-locks (lock the data-structures you use) instead of a big lock.