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Newsgroups: comp.unix.bsd.freebsd.misc Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!nntp.coast.net!howland.erols.net!EU.net!usenet2.news.uk.psi.net!uknet!usenet1.news.uk.psi.net!uknet!uknet!newsfeed.ed.ac.uk!edcogsci!richard From: richard@cogsci.ed.ac.uk (Richard Tobin) Subject: Re: SCSI tape block size X-Nntp-Posting-Host: pitcairn Message-ID: <DyzBF1.HMw@cogsci.ed.ac.uk> Sender: cnews@cogsci.ed.ac.uk (C News Software) Organization: HCRC, University of Edinburgh References: <536grc$ba@uriah.heep.sax.de> <537u8o$b8@mscu.snafu.de> <538skp$90e@uriah.heep.sax.de> Date: Tue, 8 Oct 1996 22:49:48 GMT Lines: 18 >> > (Note that 64 KB is the largest blocksize currently supported inside >> > the kernel by physio(), so there's no use in making the parameter >> > above larger.) This is not necessarily so :-) By observation, I get much better streaming with dump on my tape drive by using a blocksize of 128k compared with 64k. I guess - though I haven't checked it yet - that the reason for this is that it results in a correspondingly bigger buffer inside dump, even though the writes to the tape are no bigger. This is particularly relevant to dump, since it has to seek all over the disk, but probably affects tar and maybe even dd in some circumstances. -- Richard -- "Nothing can stop me now... except microscopic germs"