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Date:      Wed, 24 Jan 96 10:18 PST
From:      pete@pelican.com (Pete Carah)
To:        hardware@freebsd.org
Subject:   Re: QIC-3080: density & length
Message-ID:  <m0tf9m8-0000SaC@pelican.com>
In-Reply-To: <199601220134.MAA16967@genesis.atrad.adelaide.edu.au>

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In article <199601220134.MAA16967@genesis.atrad.adelaide.edu.au> msmith writes:

>C. O'Donnell stands accused of saying:
 
>> I have purchased a Conner TSM4000R SCSI tape backup unit. I have
>> found this unit mentioned several times in questions in the mail
>> archives, but unfortunately the replies must have been sent
>> directly, and not forwarded to the list.
>
>Odd, I've read lots of people saying that they're lemons.  Sorry.

Well, I was never able to get one to stream on a SS1000 that easily
streams a DLT (10g version) on the same otherwise-unused scsi port.
(nice having 3 scsi ports on your machine :-) (a customer brought
the drive in and wanted his data dumped to it instead of our default
DLT).  This was long (1/2 gb) files that have no problems with
streaming in either Sun's tar or gtar onto the DLT.  The source drive
was a sparc storage-array that is certainly both fast enough, and 
not on the same scsi port as the tape (since it isn't on a scsi port
at all)...

If you need speed and don't worry about $$$ I'd recommend a DLT,
though I've never tried one (directly; with /etc/rmt it won't
stream from either fbsd or a SS20 but I'd expect that) on freebsd 
either :-)  As long as fbsd's tape driver can handle variable
blocksize it should be fine.  

We went to the trouble of writing a shared-memory stream program and
still couldn't get the Connor drive going fast with gtar (usually
better) or Sun's tar.  There is one problem with Solaris of a
65k dma limit on the blocked-tape driver; this may be the problem
but it doesn't seem to bother a QIC525 drive.

I've never tried one on freebsd but this one experience hasn't encouraged
me.

-- Pete



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