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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!nntp.coast.net!nntp.primenet.com!howland.erols.net!nntp.crl.com!symiserver2.symantec.com!usenet From: tedm@agora.rdrop.com Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Backups Date: 6 Sep 1996 08:41:28 GMT Organization: Symantec Corporation Lines: 44 Message-ID: <50oo3o$k0u@symiserver2.symantec.com> References: <01bb9a16$b412a760$e26d04c7@zellion.cyberwind.com> Reply-To: tedm@agora.rdrop.com NNTP-Posting-Host: 198.6.34.2 X-Newsreader: IBM NewsReader/2 v1.2.5 In <01bb9a16$b412a760$e26d04c7@zellion.cyberwind.com>, "Jeffery T. White" <zellion@wco.com> writes: >I have a FreeBSD 2.1.5R system running with a 4mm DAT, WangDAT 1300, tape >drive in it. I have 2 questions: > >1. When the system boots it says: WangDAT model 1300 is a known rogue >density code 0x13, drive empty. What does it mean "known rogue" is this >good, bad or ugly? > Here is the deal on tape drives, at least as far as I can determine: Way back in the computing dark ages, there was only the SCSI-1 spec. This didn't include QFA (Quick FIle Access) a method of basically sending a "go to block number such&such" so the tapedrive didn't spend an hour seesawing back and forth getting to the block. It also didn't include disconnection, a SCSI process where you sent the drive a command and the drive accepted it and disconnected from the SCSI bus, then reconnected when the command finished. While the lack of disconnection was no big deal for devices like disks, a QIC drive that has the SCSI bus seized while it fast-forwards to the end of the tape can be painful since everything else basically halts. In any case, the SCSI-2 spec eventually came out which added all this goodness, making tape usage reasonable The problem is that during the time the SCSI-2 standard was being decided on, some tape manufacturers decided to invent their own versions of the commands. Thus, the "rogue" tapedrives such as the 1300 were born. A rogue drive is basically a drive that somebody had that they discovered wouldn't speak real SCSI-1, or SCSI-2, even while identifying itself as knowing the dialect. So, the user figured out what the differences were, and made an entry in the "Rogues Gallery" to help the tape drive along. So, if you have a rogue drive, you know for certainty that somewhere, somebody got it working. On the other hand, since it is a rogue, it is going to be first against the wall when the revolution comes. I once had one of those drives in a FreeBSD 1.1.5.1 machine, and it never worked. Of course, I could very easily have been doing something wrong. However, I replaced the drive with an Archive Python variety of some sort and it worked. I have always used tar for my backups.