I wrote:
>
> Andreas Haumer wrote:
> >
> > Hi!
> >
> > Robert L Harris wrote:
> > >
> > > When I try and read files off my jaz, usually it seems to lock my machine.
> > > It locks the scsi activity light on and if I can get to the console I get
> > > alot of errors concerning the queue. This time I didn't change the adapter
> > > defaults.
> > >
> > > Who do I work with to see about fixing this?
>
> That would be me, but you're too late :) I've already fixed certain
> problems with the Jaz drives in my latest patch, and even gone a step
> further in my "about to be released" patch. More on that in the
> announcement for my next patch.
>
> > Try disabling command queueing for the JAZ device in the adapter
> > setup. This helped for me, though I have to admit that a SCSI device
> > shouldn't completely lock up the system.
>
> In this case, the Jaz drive is reporting that it is capable of tagged
> queueing and then refusing the SCSI commands when you actually start to send
> them as tagged commands. Under the older version of my driver, this would
> result in an infinite retry of the command until it timed out, then a reset,
> then the whole process would start over. The 5.0.5 patch detects this
> condition and adjusts.
>
> > With a ncr53c8xx-based board the JAZ drive still doesn't work well with
> > command queueing, but the driver doesn't completely lock up the machine,
> > it returns an error code after a short timeout and continues working.
> >
> > With command queuing turned off for the JAZ drive it works stable and
> > well!
>
> Yes, they do. But, the problems with Jax drives and command queueing are
> deeper than what is being reported here. You were lucky, your Jaz drive
> flakes out on tagged commands and causes problems, which leads you to turn
> off command queueing and then things work fine. For versions of the Jaz
> firmware that are J.86 or less, the problem is much worse. That firmware
> will say that it can do tagged queueing, and will accept the tagged
> commands, but it will silently corrupt your data in the process. The Jaz
> drives as a whole should be blacklisted from tagged command queueing
> entirely.
--Doug Ledford <dledford@dialnet.net> Opinions expressed are my own, but they should be everybody's.
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