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Re: AO40 emergency software restart routine

At 09:23 PM 12/14/00 -0700, Vince Fiscus, KB7ADL wrote:
>Just curious here.
>Let's assume there's no hardware failure involved but that the command 
>processing system is just locked up so it's unable to process real-time 
>commands and carry out satellite house keeping. Is the command-assist 
>software separate from the rest of the system and immune from lockups? One 
>would think that command-assist would also be a casualty of the lock up 
>and that a locked up system would be unable or unaware that it should load 
>and run the software. How do command-assist and other recovery routines 
>actually work?
>Also, what sort of commands was AO40 processing when the telemetry stopped?

Vince, what I had written control software for a repeater in the past, I 
had the software regularly reset a hardware timer. If the software failed, 
the timer counted down, and when it fired, it did a hardware reset. I would 
imagine that AO-40 has a similar but more sophisticated approach, since as 
you rightly point out, if the software locks up, it won't launch a 
life-saving program itself.

Just a thought.

Dave  VE3GYQ

David B. Toth, MD    mailto:ve3gyq@amsat.org
Lima, Ohio

  "We are all ignorant, only in different ways, and no one is as
   ignorant as an educated man outside his own field" - Will Rogers  

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