News Group Posts

dds3 tape drives scsi 3

Newsgroups: comp.unix.sco.misc
From: "D. Thomas Podnar" <tom@microlite.com>
Subject: Re: SCO 5.0.6 and Scorpion 40 DDS4 Tape
Date: Sun, 24 Dec 2000 05:40:31 GMT
Message-ID: <200012240540.AAA16388@mlite.microlite.com> 

: Hi,
: We have recently purchased a Dell Poweredge 2400 which was supplied with a
: DDS4 tape drive that appears to be a rebadged Seagate Scorpion 40
: tape drive. With the tape drive config switches in the default position
: we have two problems:
: 
: 1. The drive appears to do a security erase rather than a fast erase when
: 'tape erase' is used.

Actually it is not doing an erase at all. It is headed out to left field
and will fail after a few hours.

: 2. The 'tape getcomp/setcomp' command fails with an 'illegal command' error.

Yep.

: Now, we have had no problems with Scorpion 24 DDS3 drives and 5.0.4 and so
: assumed that the 5.0.6 and Scorpion 40 combination would be fine
: (I know that this is probably optimistic!).

The DDS3 drives are "SCSI-2" compliant. By default, the Scorpion 40 drive,
and all of the drives that are OEM versions of the Scorpion (Dell, IBM,
Tecmar etc.) return a SCSI compliance level of "3".

The SCO OpenServer 5.0.x Stp driver fails in some places with drives that
report SCSI 3 compliance, including...

  o Erase/Partition
  o Set Partition
  o Getcomp / Setcomp
  o Quick File Access (the MT_LOCATE ioctl)
  o Write Setmark (it will write a filemark instead)

: So this raises a few questions:

: a.    Does anybody know what the 4 Operating System switches are on
: the tape drive? Naturally I can find information on what to set
: these switches to for various specific OSes, but not SCO!

Yep. You turn OFF switches 5 and 8. This sets SCSI 2 compliance mode
and all becomes well.

: b.    Is anyone aware of any specific SCO patches/config options that will
: allow access to to the fast erase and compression control on the
: tape drive using standard SCO software?

The appearance of devices that report a SCSI compliance level of 3 came
as a rude surprise to everyone. The only devices we've tested so far
that do this are the Scorpion 40 and its step-children, and the HP
Ultrium 230, which is an LTO drive. It doesn't have a SCSI-2 mode.
Fortunately, SCO is very aware of the issue and has been working hard
on a patch for the Stp driver. It is now in testing and should be
appearing soon for 5.0.6. We're hoping they make a supplement for
5.0.5 also.

: c.    Is there a public domain SCSI tape utility that will save me from
: writing my own utility that will issue 'appropriate' SCSI commands to
: do these operations. (Always assuming that these problems are not
: intrinsic to the tape drive.)

You won't need one. Setting the drives to SCSI 2 compliance mode will
fix the problem, and there is really no need to run the drive in SCSI 3
mode. The patch will allow the drive to run in SCSI 3 mode so if you
install it when available you won't have to change the jumpers.
Either way, you are covered. In any event, it isn't the "tape" command
that is the problem.

: Thanks

You're welcome. Happy Holidays!
: 
: Tim Wooller

Tom
---
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