Re: RT patch acceptance

Karim Yaghmour
2005-06-01T15:26:24Z

Andrea,

I've been involved with understanding/fighting this patent for a very
long time. I must have read it at least a dozen times. To the best of
my understanding as a non-lawyer, I don't see how PREEMPT_RT could
fall as being covered by it.

Andrea Arcangeli wrote:
> The patent text goes like this "providing a software emulator to disable
> and enable interrupts from the general purpose operating system;
>
> marking interrupts as "soft disabled" and not "soft enabled" in response
> to requests from the general purpose operating system to disable
> interrupts; ".

What you are refering to is claim #7. The text does resemble this, but it's
in a wider context of all the other statements within that claim, the main
part being what I quoted earlier.

Now in regards to emulating interrupts in a general purpose OS, then this
has been done many times over prior to the patent. Here's one readily
available example in the Unix world:
http://www.usenix.org/publications/library/proceedings/micro93/stodolsky.html

Please drop this one Andrea.

Karim
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