[openbeos] Re: undocumented syscalls
- From: "Bruno G. Albuquerque" <bga@xxxxxxxxxxxxx>
- To: openbeos@xxxxxxxxxxxxx
- Date: Fri, 16 Aug 2002 15:59:54 -0300 (BRT)
On Fri, 16 Aug 2002, Timothy Covell wrote:
> I'm no kernel programmer ;-( , but I do know that inb/outb are
> almost indespensible. How do you plan on implementing this
> on OBOS without write_isa_io or an equivalent?
We are writting an OS from scratch. We will implement anything we need.
> Along these lines, I'm confused about how BeOS can have
> _micro_second resolution with commands like microsleep(),
> yet have a 3ms scheduler quantum. Perhaps someone could
> explain these things in a newsletter??
Easy, it does not have a 3ms scheduler quantum.
Quoting Manuel (the indented text was the question asked):
----------
> I read that the timer tick was 1ms, and the scheduler did task
> switching on every third tick (3ms). That would give the 1ms timing
> resolution.
That's not even close to truth.
There is no periodic tick in BeOS. There is a time based callout queue
that is used by the scheduler itself. NewOS implementation is close enough
to what BeOS did to give you an idea.
----------
So, there you go.
-Bruno
Other related posts:
