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Xref: sserve comp.os.linux:47796 comp.os.386bsd.questions:3776 comp.sys.ibm.pc.hardware:60125 comp.windows.x.i386unix:2488 Path: sserve!newshost.anu.edu.au!munnari.oz.au!network.ucsd.edu!dog.ee.lbl.gov!overload.lbl.gov!agate!howland.reston.ans.net!ux1.cso.uiuc.edu!uwm.edu!cs.utexas.edu!uunet!ogicse!psgrain!agora!implode!davidg From: davidg@implode.rain.com (David Greenman) Newsgroups: comp.os.linux,comp.os.386bsd.questions,comp.sys.ibm.pc.hardware,comp.windows.x.i386unix Subject: Re: SUMMARY: 486DX2/66 for Unix conclusions (fairly long) Message-ID: <CA3pv5.56D@implode.rain.com> Date: 13 Jul 93 11:42:41 GMT Article-I.D.: implode.CA3pv5.56D Organization: Delta Systems, Portland, OR. Lines: 35 Sorry that I missed the original post, but seeing part of the following quote, I have to make some corrections to what Chris Metcalf and Piercarlo Grandi have said: >Chris> o Linux uses the disk better: shared libraries for >Chris> executables, and virtual memory is physical memory PLUS disk >Chris> swap partitions; 386BSD currently uses unshared libraries >Chris> (though apparently some people are working on this), and does >Chris> the usual BSD virtual memory technique where all virtual memory >Chris> must be backed by swap. It is true that 386BSD as it is shipped does not support have libraries. It is *not* true that it's total VM must be backed by swap. In fact if you want you can have *no* swap. The total VM in 386BSD is memory + swap. 386BSD's VM system has nothing in common with original BSD; 386BSD's VM system is derived from Mach 2.5. >On the other hand Linux does no swapping. However the BSD swapper sucks, >but maybe it's better than nothing. However overall I think that the VM >subsystem is better under BSD than Linux, even if I would love for it to >use page fault frequency as policy. This is wrong, too. 386BSD does *not* swap. The swapping code has not yet been written. 386BSD only pages. This is probably also related to the fact that 386BSD doesn't use the 'BSD' VM system. As far as performance, yes, 386BSD does use the extremely simple paging algorithm that was in original BSD. It would be nice if this was changed to do page reclaimation based on a per-process working set and page fault frequency, but it currently doesn't. -DG --- David Greenman davidg@implode.rain.com