[Info-vax] Processes hang on USB-access

[Dave Froble]

On 2/17/2022 2:27 PM, abrsvc wrote:
> On Thursday, February 17, 2022 at 2:07:29 PM UTC-5, Dave Froble wrote:
>> On 2/17/2022 4:15 AM, Joukj wrote:
>>> Hi all,
>>>
>>> I have an 2 TB USB-disk attached to a DPWS500 running OpenVMS Alpha V8.4-2L1.
>>> After a couple of hours to couple of days the process reading/writing to the
>>> disk seems to hang on the disk access. When some other process tries to access
>>> this disk in this state, it also hangs. A normal reboot of the machine is not
>>> possible anymore since also the dismount of the disk hangs. I have to reset the
>>> machine.
>>>
>>> No errors are logged for the device.
>>>
>>> What could be the problem and how can I avoid processes hanging on access to
>>> this disk?
>>>
>>> I already changed the USB-disk for a brand new one and I changed the machine to
>>> which it is connected. I think I also tried a XP1000.
>>>
>>>
>>> regards
>>> Jouk
>> I seem to recall that the USB implementation on older systems from DEC was less
>> than great. You may discover the problem with a system dump and SDA, but, then
>> what?
>>
>> --
>> David Froble Tel: 724-529-0450
>> Dave Froble Enterprises, Inc. E-Mail: da... at tsoft-inc.com
>> DFE Ultralights, Inc.
>> 170 Grimplin Road
>> Vanderbilt, PA 15486
>
> As with any "problem", knowing what exactly is wrong yields a potential solution.  With a nebulous report of "hangs", there is nothing to go on here.  Is the process waiting for an I/O completion that was missed or never occurred? An examination of the dump would answer this question.  Perhaps there is a code path that results in a deadlock and that is what happened here.  Who knows without additional investigation?
>

Correct Dan, but then what?  Re-write the driver, and add to VMS?  Perhaps a 
non-USB SSD would be an easier "fix"?

It could also be the USB hardware.

-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      E-Mail: davef at tsoft-inc.com
DFE Ultralights, Inc.
170 Grimplin Road
Vanderbilt, PA  15486