I'm trying to remember the name of a device used for detecting failure
in a real-time computer system. For example on a redundant pair of
computers the current active computer is tested occasionally by it, and
if it fails a switch to the other computer is made. The device asks the
computer to compute something like the checksum of a small message.

Deadman's switch keeps springing to mind, but it's not that.

TIA,

Jon C.

jg.campbell.ng@gmail.com wrote:
It's common to have a timer external to the microprocessor that reboots
it if it reaches zero. The software resets the clock on this timer
periodically if it's functioning. This is a watchdog timer, this maybe
what you're thinking of.

Rob Thorpe wrote:
That's it, thanks. I'm not sure where I got the checksum from --
perhaps an additional sanity check by the watchdog device?

Thanks,

Jon C.

jg.campbell.ng@gmail.com wrote:
I am not sure why you chose to post off-topic..... don't do that!