Re: Power cycling Mark IV

[Tom Droege <tdroege@veriomail.com>]

Chris and all,

I think the stamp code can be written so that it never needs to be 
reset.  My proof is that I never need to reset the stamp although it has a 
reset button.  It is just never used.

OK, some of you might operate in a way that you need to reset the 
stamp.  You are free to do so.  There is a reset button that can be 
replaced with a variety of switches.  I think an optical switch would also 
work.  There is a power bus nearby.

I think I will just wait and see how it goes.

Chris, have you succeeded in writing any code to the stamp?  I always have 
a problem writing to it thought it should be possible from the manual with 
the switch I have provided on the Stamp pc board.  I am not sure that stamp 
code is something that we want to be under continuous development.  We 
shall see.  I think the same thing holds for the prom code.  Changes will 
be a major effort, I think.

Tom Droege

At 09:09 PM 9/27/00 -0700, you wrote:

>I was going to answer Tom's remark about not needing a STAMP
>reset about the same was as Arne.  Yes if there are no bugs
>in the STAMP code it will never need to be re-set.  When I
>design things I always assume there are and will always be
>software errors.  With luck the STAMP code will be under
>continuos development.  Many of the Mark IV systems will be
>operated remotely.  If there was a reset I'd build it into
>the routine that handle serial communication with the STAMP.
>It would send a message then if nothing came back after a while
>do a reset and re-send the message.  I think we could use an
>unused serial control line.  One of those meant for modems.
>
>It was pointed out that the Control PC could "stop talking"
>The most likely thing to happen is a failure of the real-time
>control software.  This can be fixed remotely.
>If it is due to a hardware failure there is nothing to be done.
>The OS could crash or lock up but that is highly unlikely
>but if you are worried about that you can buy a hardware watchdog
>card that will reboot the PC if the OS crashes.  So we can
>fix any software caused problem on a PC without being on site.
>With a STAMP reset function we could fix any STAMP software
>problem remotely also.
>
>aah@nofs.navy.mil wrote:
> >
> > Tom,
> >   You have already stated that you haven't implemented
> > all of the necessary traps to prevent the Stamp from hanging.
> > Until someone writes the perfect software program, there
> > will always be instances of hangs and screwups.  Granted,
> > most of those at this stage will be hardware problems, but
> > I run the system unattended and can't be prepared to
> > "take that 90 foot walk" since I don't live next to the
> > telescope.  Same goes for other sites, I'm sure.  Why are
> > you so set against implementing a remote reset for the Stamp?
> > It gives the programmer a chance to either recover from
> > a hardware failure, log the failure properly, or at least
> > stow the system in a safe position.  As I've said before,
> > I don't give this particular feature high priority, but
> > it seems like a reasonable feature to me.
> > Arne
>
>--
>    Chris Albertson             home: chris@albertson-home.net
>    Redondo Beach, California   work: calbertson@primeadvantage.com