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Newsgroups: comp.unix.bsd Path: sserve!manuel!munnari.oz.au!spool.mu.edu!uunet!sun-barr!ames!sgi!rigden.wpd.sgi.com!rpw3 From: rpw3@rigden.wpd.sgi.com (Rob Warnock) Subject: Re: DAT tape (SCSI) supported? Message-ID: <q1v33vs@sgi.sgi.com> Sender: rpw3@rigden.wpd.sgi.com Organization: Silicon Graphics, Inc. Mountain View, CA Date: Sat, 19 Sep 1992 13:59:35 GMT Lines: 41 kuku@acds.physik.rwth-aachen.de writes: +--------------- | Recently I saved all my user data etc. from a SCO system to a DAT tape | (TLZ04, DEC attached to a 1542), scratched the disk (intentionally) and | now I'm starting to build up a 386bsd on it. +--------------- I sure hope you didn't use a monster record size when you wrote your DAT tape on the SCO system! Oh, you used a 1542... It's probably o.k. But some Unix workstation users routinely use 256KB record sizes for DAT, which won't work with 386bsd. (Yet.) +--------------- | My question: will there be a chance in the near future to get that data | read back into the 'new born' 386BSD system by means of a 386BSD DAT SCSI | driver? +--------------- Sure. the "driver" is already there, in the normal SCSI driver. You just need to make Scott Burris's 2-line fix for variable-block tape to "as.c", and it works fine. I can exchange DAT tapes between 386bsd and SGI Indigos, for example. Note: There are still some bugs in the SCSI driver and/or tape support when it comes to large read()/write() sizes and end-of-file handling. Fortunately, both "tar" and "cpio" write sentinals on the end of their archives, so you never need to read the actual EOF. Just use the default "tar" block size (10240) or "cpio -B" (5120), and you should be o.k. I get about 160 KB/s when backing up the disk with "tar cvf /dev/dat" (which is just linked to /dev/ras3a). -Rob ----- Rob Warnock, MS-9U/510 rpw3@sgi.com Silicon Graphics, Inc. (415)390-1673 2011 N. Shoreline Blvd. Mountain View, CA 94043