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Re: TASS UPS, Tech Note.

There is a watchdog timer in the Mark IV design.  There are also 
available lines both logic level signals, and power control signals, i.e.
they can turn AC power on or off.

The question is, what to do with such signals, if anything.  

Tom Droege

On Fri, 22 Aug 1997, "John D. Gwinner" <gwinner@northnet.org> wrote:
>> Yep Chris, there are two groups.  
>> >To this second group of people the way one shuts down a computer
>> >is to first post notices on company bulliten boards saying "The
>> >XXX system will be shutdown next Tuesday from 1:00am to 3:00am
>> >to install a new set of disk drive.  Sorry for any trouble this
>> >may cause."
>> >
>I loved your bulletin board example, Chris! <LOL>
>> Actually there is a third group
>> > that builds systems even more primative than DOS.  Though we seem
>> to be a dying breed.  There seems to be an OS in my Waffle maker
>> these days.
>These computers outnumber their desktop brethren by 10:1 believe it or not.
>Your car has five or ten, microwave, TV, remote control ... 
>> I think each has it's place.  I would do the real time running with
>> a simple machine, say DOS based as we are doing.  
>Be careful though is my point ... even DOS keeps files open now days!  For
>example, your application is running (or isn't, at which point resetting
>with open files would be necessary and desired ), and disk cache's or even
>hard drives themselves may have buffers that aren't written to disk!
>Many modern hard drives have 'write through' or 'write delayed' buffers. 
>Admittedly, that old clunker 8088 probably doesn't, but it's been pretty
>common for a while. (might be something you can disable)
>> On the other hand, if the real
>> time machine crashes, we have lost that data block anyway.  No sense
>> worrying about it, or trying to restart where we left off, as the 
>> sky is gone.  
>Right (I mentioned this originally also, to partially contradict myself).
>However, I think if a cheap solution, like the UPS 'I'm shutting down'
>signal can be duplicated, or the watchdog Card (how much does a TASS IV
>cost anyway?), then I'd feel safer.
>Is it too late to design a watchdog into the TASS card itself? (probably)
>		== John ==