Weekly Classic Computer Trivia Question (20150112)

Johnny Billquist bqt at update.uu.se
Mon Jan 12 12:57:32 CST 2015

On 2015-01-12 19:48, Vincent Slyngstad wrote:
> From: Johnny Billquist: Monday, January 12, 2015 10:42 AM
>>>> And of course, you also have things like OS/8, which runs with
>>>> interrupts off at all times, to which the answer to the original
>>>> question would be "OS/8". :-)
>>> Exactly :-)
>> But anything running constantly with the interrupts off should not be
>> in the "competition". As it's hardly called latency when you just
>> ignore the signal.
> What I've seen is systems that collect data with interrupts on, but do
> have to turn interrupts off when calling OS/8 services, or OS/8 will crash.
> AFAIK, all OS/8 services and drivers require this, even things like the
> RK05 driver.

Right. But it's not that things will crash in OS/8, but you will get 
interrupts as a result of OS/8 operations, which you most probably do 
not want, and might not even know how to deal with. And stealing the 
completion of an operation through an interrupt might mean OS/8 never 
notice that an operation completes.
So you will get OS/8 hangs, and your interrupt system will get 
interrupts you never expected.


Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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