SCSI Controller Hanging...

David Brownlee abs at
Fri Jan 26 03:44:31 CST 2018

On 24 January 2018 at 16:33, Jack Harper via cctalk
<cctalk at> wrote:
> Hello Plamen -
> I use the SCSI controller that is built into the MVME177 transition module.
> No, when I RESET the system, I just press the RESET button on the processor
> board - usually when it is hung with my software.  On this system, I only
> code in 68K assembly and so I do see the "occasional" hang :)
> Is the "SCSI reset option" part of the 68K/BUG RESET command?
> In my documentation - and I easily may not have the latest documentation - I
> only see RESET options to force a COLD or WARM start on hardware RESET.
> The documentation that I have also cautions: "...may cause the disk
> controller to be out of phase with respect to the disk configuration tables
> in memory", which certainly makes sense.
> However, I do not modify any of those tables from system default.
> I appreciate your input.

Do you have any other software you can use to test the hardware - if
it experiences the same issues then you know its hardware related.

I think NetBSD supports the MVME177 board ( ) I'm
sure there are others.

You also mention you have multiple VME boards in the cage and multiple
SCSI drives. Does the issue occur when you strip everything down to a
single board set and drive?

(*) Theoretically other CPU boards may not be able to affect the SCSI,
but a near first rule of hardware strangeness is to pull everything
thats not needed so you can be sure :)


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