RT/embedded OS use poll

On Dec 28, 12:49=A0am, Przemek Klosowski <prze...@tux.dot.org> wrote:

> Well my Samsung BlueRay player, and my TV, and my smartphone, and both
> wireless routers are all running Linux inside. They are all realtime in
> the sense that they manage to do what they =A0need to do, in time for whe=
n

Ooh, big asterisk on that though. I don't know what's in the Blu-Ray
player, but in the case of the cellphone, the baseband processor is
almost certainly a separate core running dedicated (non-Linux) code.
The code running on the Linux core(s) is app code, not much
realtimishness.

Similarly, the TV set likely does much of the "really RT" stuff in
hardware in an ASIC.

On Tue, 28 Dec 2010 04:07:19 -0800, larwe wrote:

> Ooh, big asterisk on that though. I don't know what's in the Blu-Ray
> player, but in the case of the cellphone, the baseband processor is
> almost certainly a separate core running dedicated (non-Linux) code. The
> code running on the Linux core(s) is app code, not much realtimishness.
> 
> Similarly, the TV set likely does much of the "really RT" stuff in
> hardware in an ASIC.

My favorite realtime story told by someone who's been in business 
forever. Long, long ago he had military customers with a new mysterious 
project and were asking about the capabilities of his product: "It 
absolutely has to be real-time: the maximum allowable latency cannot be 
exceeded". He asked for the value of the latency, and was told it was a 
couple hundred seconds.  The bottom line is, real time doesn't have to be 
fast---it has to be fast enough for the job.