Re: [PARPORT] Tape backup with mt & tar


Art Wildman (wildman@mediaone.net)
Wed, 25 Aug 1999 01:07:35 -0400


Thanks for the detailed explanation, I had no idea the problem requires a kernel
hack - thought something may have been broke with my version of mt.

1) Thanks for your work! - we depend on you guys to help make all this cheap
hardware we slap together work over an ancient parallel port. I could always go
out and buy an expensive SCSI Tape Drive and PCMCIA contoller, but that would
cost more than my laptop, and wouldn't be any fun.
2) Just a thought from leftfield - Does the "ftape" loadable kernel module use
the same conventions for writing EOFs? - the drive hardware is similar although
the interface is different. Perhaps you could borrow something from the ftape
sources. Hope this helps -good luck.
FTAPE Homepage...
"ftape supports drives that conform to the QIC-117 and one of the QIC-40,
QIC-80, QIC-40, QIC-3010, and QIC-3020 standards as well as the Ditto 2GB and
Ditto Max (Pro) tape drives which partly use proprietary extensions of the
QIC-117 command set. ftape supports also certain kinds of parallel port tape
drives. Check out the Ftape HOWTO for more details.

ftape supports neither QIC-02, IDE (ATAPI), nor SCSI tape drives. SCSI drives
are accessed as /dev/[n]st[0-7] and are supported by the kernel through the SCSI
drivers. ATAPI tape drives are supported by the kernel since 1.3.46 through the
IDE drivers."
http://www.math1.rwth-aachen.de/~heine/ftape/introduction.html
http://metalab.unc.edu/LDP/HOWTO/Ftape-HOWTO.html
http://www.torque.net/ftape/archives/faq/html/ftape-faq.html

Linux Journal Backup Articles
http://linuxjournal.com:82/lj-issues/issue22/backlinux.html
http://linuxjournal.com:8080/lj-issues/issue22/1216.html
http://linuxjournal.com:8080/lj-issues/issue22/backup.html

"J. Scott Berg" wrote:
>
> On Tue, 24 Aug 1999, Art Wildman wrote:
>
> > # mt -f /dev/npt0 fsf 1
> > pt0: HP COLORADO 8GBe, master, blocksize 512, 4007 MB
> > pt0: Unimplemented mt_op 1
> > /dev/pt0: Invalid argument
> > ... how do I skip forward to next archive???
> >
> > This makes storing multiple tar files on a tape useless, if you
> > can't retrieve them. Please explain what's going on.
>
> Pretty much what it says: "unimplemented mt_op." The only mt
> operation implemented at this point is rewind, as you discovered.
> I've implemented the filemark-related mt ops, but there are a couple
> issues to get settled before releasing it to prime time:
>
> 1) This is the first time I've written anything into the kernel
> proper, so there's a substantive chance that it will crash your
> kernel. It doesn't crash mine, but YMMV. Actually, what I've done is
> virtually identical to what is done for a rewind, so I would hope it
> would be harmless, but I'm waiting for feedback to make sure.
>
> 2) As far as I can tell, the SCSI tape driver and the IDE tape driver
> both have different conventions for writing filemarks. I've adopted a
> third one B~). I think (?) the different conventions are irrelevant if
> you never make a weof mt ioctl.
>
> Since I sent this to Grant 1-1/2 weeks ago and haven't heard back,
> I'll post the kernel patch (against 2.2.11) with the cavaet that you
> don't complain when it trashes your hard drive and that you promise
> not to try to write filemarks. Please send me any feedback.
>
> --
> J. Scott Berg jsberg@earthlink.net
> 3025 E. Amy Ln. (812) 339-8368
> Bloomington, IN 47408-4220
>

-- 
   Art Wildman - wildman@mediaone.net    
"Share what you know. Learn what you dont."   - dejanews.com Motto

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