at&t unix pc

[Ethan Dicks]

On 10/14/10, Eric Smith <eric at brouhaha.com> wrote:
> Ethan wrote:
>>> I never got to the stage of having a reliable driver.
>>>
>> Ah.  Out of curiosity, did you happen to write it from scratch or did
>> you have existing UNIX 5380 drivers to "borrow" from?
>>
>
> I was working from scratch, and was finding debugging to be exceedingly
> difficult.

Indeed.  I've done communication device driver work in the past - and
seen many kernel panics - it was fun back then - your terminal session
rhythm would go "off" as your process was no longer being serviced,
then there'd be the tell-tale chatter of the console printer reporting
the unhappiness followed by a 20 minute dump and reboot cycle.  Some
things are better left in the past.

> These days it would be somewhat easier as I have a good
> logic analyzer I could hook up to the MC68010.  (An in-circuit emulator
> would be even better.)

Something like that, I do happen to have (a Northwest Instruments
"Satellite" bus analyzer that can capture and store the last 4096 bus
cycles... it was $20K when it was new, but I got to keep it when the
company doors closed.  I've found it quite handy for debugging
hardware and hardware/firmware issues.  I haven't fired it up in a few
years - this thread reminds me I should check it - the sampler box is
no doubt fine, I'm sure, but the "head" is an IBM 5150 PC with an
ST225 - I'm anticipating stiction issues.).

-ethan