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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!simtel!zombie.ncsc.mil!news.mathworks.com!newsfeed.internetmci.com!news.sprintlink.net!helena.MT.net!nate From: nate@trout.sri.MT.net (Nate Williams) Newsgroups: comp.unix.bsd.freebsd.misc,comp.os.linux.hardware Subject: Re: Tape backup speed FreeBSD v. Linux Date: 31 Oct 1995 17:22:46 GMT Organization: SRI Intl. - Montana Operations Lines: 38 Message-ID: <475m16$fuu@helena.MT.net> References: <1995Oct30.090118.28117@state.systems.sa.gov.au> Reply-To: "Nate Williams" <nate@sneezy.sri.com> NNTP-Posting-Host: trout.sri.mt.net Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:8052 comp.os.linux.hardware:19905 In article <1995Oct30.090118.28117@state.systems.sa.gov.au>, <chdemgt@state.systems.sa.gov.au> wrote: >This is a new Tandberg 1200S TDC4120 QIC-1000 tape drive. Being decoded, that >is a SCSI-2 1.2 GB DC-600 quarter-inch cassette drive. It was bought for a >FreeBSD system but the performance was disappointing. The computer (a >486DX4/100 with a Seagate SCSI-2 hard disk drive) also has a small Linux >partition which can be booted with the help of a floppy disk. Here are the >data rates on backup: > >Claimed by Tandberg in the spec: 12/18 MB/min >FreeBSD 951020 SNAP: 9.1 MB/min >Linux 1.2.x (forget exactly): 15.4 MB/min How are you measing the data rates? Try: dd if=/dev/null of=/dev/rst0 bs=1k count=100 This is a good test to see how fast the device is, and removes any problems you may have with an overloaded controller, different layout of the FS, etc.. >The something was wrong could be detected at once by ear. On FreeBSD the tape >seems to run forward for 1.5 sec and then back for 1.5 sec. This means that somehow the tape drive isn't getting data fast enough to stream with FreeBSD, and not a problem with the tape device driver. Nate -- nate@sneezy.sri.com | Research Engineer, SRI Intl. - Montana Operations nate@trout.sri.MT.net | Loving life in God's country, the great state of work #: (406) 449-7662 | Montana. Wanna go fly fishing? I don't charge or home #: (406) 443-7063 | feed you, but I do know the area pretty well.