Date: Thu, 14 Dec 1995 22:18:19 +0800 (WST) From: Julian Elischer <julian@jhome.DIALix.COM> To: mbarkah@hemi.com (Ade Barkah) Cc: hackers@freebsd.org Subject: Re: Anyway to get tape head past end of tape mark ? Message-ID: <199512141418.WAA05904@jhome.DIALix.COM> In-Reply-To: <199512132215.PAA23386@hemi.com> from "Ade Barkah" at Dec 13, 95 03:15:12 pm
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> > Hello, > > Uhm, I managed to get an end of tape mark to be written at the > very beginning of one tape. I don't know much about tapes, but > I think that means there are two filemarks written there now. on some drives this is true. > > Q: how can I recover from this ? overwrite it.. > > The tape is a Wangtek 5150es (SCSI), attached to a FreeBSD 2.0.5 > machine. I'm wondering several questions: > > 1. Is EOT really signified by two filemarks ? well, QIC drives know EOD without the extra mark (from memory) > > 2. Is this behaviour hardware or software ? That is, can software > force the tape to go pass the EOT ? you should be able to 'read' past all the data and then start writing, as long as you never read the EOT marks. That SHOULD overwrite it.. > > 3. If it's software, can I simply use the tape's MTFSF ioctl to > skip over the two filemarks, or do I need to modify the driver ? > that should work, but some drives recognise 2 EOF marks as special and will only allow you to write past them and not read past them.. > 4. If it's hardware, can I cut a few feet at the beginning of the > tape (hopefully past the EOT mark) and recover that way ? How > much of the tape should I cut ? Can I maybe do a 'cat /dev/nrst0 > > /dev/null' to force the tape to get to the EOT, eject without > rewinding, then cut just past that ? > no idea if this would work is nthere DATA on the tape you are trying to read? > Thanks in advance for any help, > > -Ade Barkah > -------------------------------------------------------------------- > Inet: mbarkah@hemi.com - HEMISPHERE ONLINE - www: <http://hemi.com/>; > -------------------------------------------------------------------- >
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