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Date:      Wed, 21 Apr 1999 13:17:30 -0500 (CDT)
From:      David Kelly <dkelly@mail.HiWAAY.net>
To:        freebsd-scsi@FreeBSD.ORG, girgen@partitur.se
Subject:   Re:  seagate python taper?
Message-ID:  <199904211817.NAA11540@mail.HiWAAY.net>

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Palle Girgensohn <girgen@partitur.se> writes:
> Seagate Python DDS-3. On FreeBSD 3.1 with 1542-CP? Is it OK. I read a
> message from a year ago that stated:
> 
> > Just for your information! Don't use any combination of Seagate Python DAT
> > drives, Adaptec 2940 SCSI controller and FreeBSD or Linux!
> 
> http://www.freebsd.org/cgi/getmsg.cgi?fetch=39897+0+/usr/local/www/db/text/1998/freebsd-scsi/19980222.freebsd-scsi

I followed the above to Deja-news and didn't find much more than 
discussion of audio over DAT and SGI's special firmware.

I have an Archive/Conner/Seagate Python DDS-2 drive attached to an
Adaptec 2940 (an old one, not even Ultra, just Fast). Works fine.

Also have a DDS-1 Python connected to a newer 2940. Also works fine
(only tried under 2.2.8 and older):

ahc0 <Adaptec 2940A Ultra SCSI host adapter> rev 1 int a irq 11 on pci0:15:0
ahc0: aic7860 Single Channel, SCSI Id=7, 3 SCBs
(ahc0:6:0): "ARCHIVE Python 25601-XXX 2.75" type 1 removable SCSI 2

Searched Seagates site and found: 
http://www.seagate.com:80/support/tape/tapeinfo/w4m_diff.shtml which
says:

	The Python DAT drives are fully DDS, DDS-DC, DDS-2, SCSI 1,
	and SCSI-2 compliant.

Suggesting you either have a Python, or you have a DDS-3 drive, not
both. The Seagate DDS-3 drives are known as Scorpion.

I have run about 200 tapes thru 4 Scorpion-24 DDS-3 drives attached
to (2) Asus SC875 controllers in (1) FreeBSD 3.0 (Feb 8 SNAP).
What problems I have had are not directly related to the tape drives.
Reading tape to HD, I see about 1MB/sec (uncompressed tape). Writing
10k blocksize runs about 700k/sec, even when writting to all 4
tape drives at once. (I do this a lot).

Using tcopy to read from one drive, write to another pokes along
at 300k/sec. Since installing this system there have been numerous
changes to -CURRENT's scheduler but I am no longer in a position
to update the above system.

Seagate DDS drives with hardware compression ship from the factory
with compression as the default setting. Suggest if you wish to 
be compatible with anyone else's system that you turn off the
compression jumper. You can always enable compression with mt(1)
if you need it. If the other system has compression too then
compression will be compatible, but not everybody has hardware
compression.

--
David Kelly N4HHE, dkelly@hiwaay.net (hm)
======================================================================
The human mind ordinarily operates at only ten percent of its
capacity -- the rest is overhead for the operating system.


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