The ellipsis at top and bottom mean e.g.
... jmp test ...
is the same as
... jmp test jmp test ...
is the same as
... jmp test jmp test jmp test ...
etc In the same way one might fill all remaining unused locations with e.g.
... jmp reset ...
Cheers Robin
umm... i'm pretty sure various engines in the 1800s had teh equivalent of watchdog timers and so did (and do) many mainframes.
Can you name any of these mainframes ?
I do not see a reason why anybody would use them.
In computer systems with memory protection hardware, illegal addresses, garbled data or garbled code usually caused segment fault, parity error traps and illegal opcode traps, i.e. hardware interrupts that are vectored into kernel mode space. The interrupt handler may then decide what to do, try to recover or print CRASH and dump the registers on the console and then halt or reboot the system.
On mainframes with a separate console processor, the console processor may try to check the sanity of the main processor, but even then, the decision to reboot is usually done manual.
Paul
Well, back in those days, the watchdog timers would usually come in the shape of trained personnel. They'ld be taught to check certain status indicators on a regular basis, and raise a fuss if anything appeared to be out of hand..
The classical example of a pre-computer age watchdog would be the "dead-man switch" on locomotives. Unless disarmed regularly by the chauffeur, it would bring the train to a stop.
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