>Adam D. Bradley writes:
[...]
>> I think the Win-printer software would more acurately fall into
>> the third category, "Firm Real-Time".
>>
>> Under Hard RT, the program's value goes to negative infinity if a
>> deadline is missed. (The cost of paper and ink is hardly negative
>> infinity, so this definition doesn't quite seem apropriate.)
>Then hard real-time does not exist, since "negative infinity" would mean
>the destruction of Earth and an afterlife consisting of eternal torment.
>You just classified _everything_ as "Firm Real-Time".
You can't get a true "negative infinity", it is rather a cost so high that
it is unacceptable in all cases - for anybody.
Such as a nuclear plant exploding, a plane crashing, or
other massive destruction. Taking that cost will never
be considered, even if some company may be able to
afford the cost of replacing a few nuclear plants.
>I'll accept "value function with discontinuity" though, or perhaps
>"binary value function". (and forget about the "firm" catagory)
The "firm" case have a cost that may be low or high, but
calculating with the cost is allowed. I.e. if the winprinter fail on one
out of x pages then we look at what is cheapest: replacing the printer,
improving the RT software, or reprinting one out of x pages.
Just as quality control in a factory.
Helge Hafting
-- ----------------------------------------------------------- helge.hafting@daldata.no -----------------------------------------------------------
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