DDS Tape problems

Ted Mittelstaedt tedm at
Tue Jun 21 22:34:15 GMT 2005

>-----Original Message-----
>From: owner-freebsd-questions at
>[mailto:owner-freebsd-questions at]On Behalf Of Alex Zbyslaw
>Sent: Tuesday, June 21, 2005 9:56 AM
>To: Jerry McAllister
>Cc: freebsd-questions at
>Subject: Re: DDS Tape problems
>Jerry McAllister wrote:
>>>Windows drivers could easily be doing something clever to
>compensate for
>>>some known (to Microsoft at least) problem with the specific tape
>>>drive.  Being Windows it wouldn't bother to tell you.
>>That is probably true.   I just wish someone could find out
>what that[those]
>>trick[s] is[are] and apply them in FreeBSD - someone who knows
>more about
>>SCSI tape drivers than I.
>That's not me I'm afraid :-(
>Have you found any references to the kind of  problems you've had for
>related OSes like Open/NetBSD or even Linux?

Under FreeBSD 2.2.8 they had a thing in the SCSI driver code called a
"Rogues gallery" AKA "quirks" that was used for correcting buggy

When CAM came out in FreeBSD, the SCSI code authors apparently decided
every tapedrive now would correctly implement the ANSI scsi 2 sequential
command set.  Of course this isn't true.  At that time a lot of my old
drives stopped working.  I think that they tried putting the same thing
in CAM later on, but I don't think it works.  As for my QIC cartridges, I
eventually discovered that the 525MB Tandberg QIC drives worked properly
reading and writing.  I came across a reference at some point indicating
one of the FreeBSD SCSI developers had one of these drives so I think
that the developers screwed themselves as well on this one.

I've never gotten around to filing a PR because of the difficulty of
up a dual-boot system to test out all this.  The only SCSI card that was
really supported well under 2.2.8 is the Adaptec 1540, and 1740 EISA

Fortunately, both DDS3 and QIC drives are cheap on Ebay so it is easier
just buy another drive manufactured by someone else.


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