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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mel.connect.com.au!news.syd.connect.com.au!gidora.kralizec.net.au!not-for-mail From: bde@zeta.org.au (Bruce Evans) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Wht does my dd to /dev/rsd1a claim it is read only? Date: 25 May 1996 22:11:31 +1000 Organization: Kralizec Dialup Unix Lines: 34 Message-ID: <4o6tdk$g5c@godzilla.zeta.org.au> References: <31A4D266.41C67EA6@systemics.com> NNTP-Posting-Host: godzilla.zeta.org.au In article <31A4D266.41C67EA6@systemics.com>, Gary Howland <gary@systemics.com> wrote: >I am running FreeBSD 2.1, and have two _identical_ (including the >data) SCSI disks. I am trying to use one disk as a nightly >backup, but the following commands fails: > > dd if=/dev/rsd0a of=/dev/rsd1a bs=4096k > >It fails with: > > dd: /dev/rsd1a: Read-only fileystem > 1+0 records in > 0+0 records out The whole disk (or whole slice) device /dev/rsd1c contains a write protected label in its second sector. /dev/rsd1a happens to overlap /dev/rsd1c, so the write fails when it hits the label sector. To copy the whole BSD slice, you could try dd if=/dev/rsd0c of=/dev/rsd1c bs=4096k but this should fail for the same reason. It might work if the target slice is unlabeled (then the target device would have to be named /dev/rsd1sN since c partitions don't exist on unlabeled slices). To copy the whole disk, you could try dd if=/dev/rsd0 of=/dev/rsd1 bs=4096k This bypasses the write protection on the label(s) (this is a bug), -- Bruce Evans bde@zeta.org.au