[ECOS] Is eCos a hard real-time operating system?

Andrew Lunn andrew.lunn@ascom.ch
Mon Dec 4 08:46:00 GMT 2000


> I would like to know if eCos is categorized as a hard real-time operating
> system. How deterministic the overall behavior of the system is. Often
> RTLinux is categorized as meeting hard real-time requirements, what about
> eCos? Is there any figures comparing RTLinux with eCos?

Whats your definition of Hard Real Time?

eCos does not have a deadline based schedular with guarantees, so to
me its not a hard real time OS. It does have a multi priority level
schedular. If you make your hard real time tasks run with higher
priority than your soft real time threads it will do its best to run
those first till they block. If you have too many HRT threads it will
run out of CPU. I would expect a HRT OS to refuse to even start if it
knew it could not meet all its deadlines. 

Maybe i have a different definition of hard than you? 

        Andrew


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