> From jgraham@defender.VAS.viewlogic.com Wed Jan 31 15:37 PST 1996
> Date: Wed, 31 Jan 96 15:34:55 PST
> To: Chris_G_Demetriou@NIAGARA.NECTAR.CS.CMU.EDU, greywolf@CAPTECH.COM
> Subject: Re: NCR Driver Problems
> Cc: Christoph Badura <bad@flatlin.ka.sub.org>,
>         Brad Walker <bwalker@musings.com>, current-users@netbsd.org
> 

<stuff deleted>

> Are there any drives newer than, say, two years old which don't handle
> tagging?
> 
> Should not the SCSI driver attempt to determine whether or not the drive
> handles tagging, and disable tagging for that drive if tagging fails?
> 

There are lots of SCSI devices that don't support tagged cmd queueing.

And the best way for this to be handled is really to have the
target driver query the host bus adapter (HBA) to determine if
the target supports tagged commands. If the target does then the
target driver should hand off as many commands as possible to the
HBA. At this point the HBA deals with transfer and resolution of
the commands.

-brad w.