Date: Sat, 8 Apr 1995 15:17:51 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-hackers@FreeBSD.org (FreeBSD hackers) Subject: Re: Arcive Viper QIC150 and tar Message-ID: <199504081317.PAA05000@uriah.heep.sax.de> In-Reply-To: <199504081242.HAA20164@bonkers.taronga.com> from "Peter da Silva" at Apr 8, 95 07:42:04 am
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As Peter da Silva wrote: > > The Viper 150 has one annoying firmware bug^H^H^Hfeature: in order to > > append files to the tape (or should i call them ``extents''?), you'll > > have to ``mt fsf'' until you see the first BLANK CHECK (st0: no data). > > I was under the impression that you couldn't append data to a QIC tape, > due to the erase head geometry. Is this wrong? I dunno how they make it, but it actually works. I'm using it all the time, and it's really time to get the ``mt eom'' feature back. Without it, i'm under the impression that the Viper does always write two file marks between tape files (so you have to ``mt fsf 6'' in order to skip to the 4th file). With the SPACE FORWARD TO END OF RECORDED MEDIUM command, this doesn't happen. (Maybe, it's rather a hidden bug in BSD's st code however.) There have been rumours that this is impossible, back in the days when we've been working with Data General's DG/UX release 4.3<something>. Magically enough, with the appearance of DG/UX 5.4, it started to work. I later looked into their tape driver source in order to find why it worked on DG/UX and failed on FreeBSD, and thanks to their comments, i found about this (mis)feature. (They compensated for it in the driver and have hidden it from the users. But then, they do only actively support three of four different SCSI tapes.) -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ Never trust an operating system you don't have sources for. ;-)
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