| When the DS90's were DVT't following competion of the design it was
shown that they did not go to a break condition on power up, or power
down. Some things have changed over the years, especially in the DC-DC
converter and there is a remote possibility something has changed.
Support Engineering is procuring a late model DS90 and I'll show them
how to conduct the test when it arrives.
All FLASH Ready DS700's and all DS900's have circuity that prevents the
unit from generating a break at power up/down. Why do you assume they
do?
Let me make one other comment. If you read the note that Jim pointed
to earlier in this string regarding what I found when this problem was
first discovered on the original DS700's (no longer in production)
you'll recall that on some VAX's the port the DS700 was connected to
was generating the break condition, not the DS700. Once power is
removed all we can do in hardware is prevent our own drivers from
crossing the 0 volt threshold. If the other end is pulling up the line
there is little that can be done to stop it. Has anyone bothered to
put a scope on the line is question to see what is happening?
Loren
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| >> All FLASH Ready DS700's and all DS900's have circuity that prevents
>> the unit from generating a break at power up/down. Why do you
>> assume they do?
I'm assuming nothing. I'm only going by what you wrote in 2474.2
regarding what I thought you had written to be a fix for the 700 and
900 series.
I would be quite happy to go back to the customer and tell them that
the DS90 does not generate a break or any other condition that causes
his Sun systems to crash. But the customers perceptiona and his
reality, is that when the DS90M looses power, his Sun's crash.
Now if I could convince the customer to temporarily plug one of his
Sun console ports into a dumb terminal and then have him power down
the vt, this might also be proof one way or the other that the DS90M
is either guilty or innocent of causing the system failures.
The customer has contacted Sun and they have stated that a break
condition will cause a system crash.
So if we can show good faith on our part that DS90M's at least the ones
that he has are not the culprit all well and good. I look forward to
the results of your testing.
Thanks,
Al
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