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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.ysu.edu!news.radio.cz!newsbastard.radio.cz!news.radio.cz!CESspool!news-feed.inet.tele.dk!news.maxwell.syr.edu!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!news.mindspring.com!usenet From: kpneal@pobox.com (Kevin P. Neal) Newsgroups: comp.os.linux.misc,comp.os.linux.networking,comp.os.linux.setup,comp.unix.bsd.bsdi.misc,comp.unix.bsd.misc Subject: Re: User-space file systems. (Re: Linux vs BSD) Date: Thu, 06 Mar 1997 04:07:00 GMT Organization: Bedroom Retrocomputing Lines: 37 Message-ID: <5flftc$krn@camel2.mindspring.com> References: <5e6qd5$ivq@cynic.portal.ca> <5f283t$667@cynic.portal.ca> <5fj9q4$s0i@pulp.ucs.ualberta.ca> <5fjek4$gtm@cynic.portal.ca> <5fk1t1$3mq@web.nmti.com> Reply-To: kpneal@pobox.com NNTP-Posting-Host: user-168-121-39-4.dialup.mindspring.com X-Server-Date: 6 Mar 1997 04:07:08 GMT X-Newsreader: Forte Free Agent 1.0.82 Xref: euryale.cc.adfa.oz.au comp.os.linux.misc:162937 comp.os.linux.networking:70954 comp.os.linux.setup:101092 comp.unix.bsd.bsdi.misc:6218 comp.unix.bsd.misc:2723 peter@nmti.com (Peter da Silva) wrote: >Look at it this way... I used a microkernel type operating system for years, >on my Amiga. The most common tool that was implemented there of all the things >a microkernel could do that a monolithic kernel can't, was new kinds of file >systems. If you can do userland file systems you get 95% of what people want >microkernels for anyway. Except on the Amiga, it was difficult for one filesystem to "get in bed" with another filesystem. Hence the need to NFS mount a directory that you are NFS exporting by that same machine (because if you write to the disk underneath the NFS export you lose). Anybody wanna see the Andrew File System on an Amiga? I bet it'd be very difficult. How do "current" microkernels avoid this? Also, I disagree with you in saying that the "most common tool" implemented via the microkernel was filesystems. I think device drivers were more common. They ran outside of the kernel, and could in theory be cut off later. They also didn't require any funky LKM code, or funky addressing, or funky anything -- they basically looked like Amiga shared libraries. * Wasn't the BSD portalfs designed to make userland filesystems easier to implement? Whatever happened to it? -- XCOMM Kevin P. Neal, Junior, Comp. Sci. - House of Retrocomputing XCOMM mailto:kpneal@pobox.com - http://www.pobox.com/~kpn/ XCOMM kpneal@eos.ncsu.edu " *** StarDOS makes great coffee! ***" XCOMM From a mid-80's advertisement in "Compute's GAZETTE", a C64/C128 mag