> Well the hardware should not matter and the startup code should be
> finished in
> several milli seconds, of course.
> Most probably are ARM. PPC or SH4 platforms used in automotive
> In the automation industry the boot time is not that important -
> therefore a
> lot of PC compatible boards are used.
The reason I ask about the hardware is so that I can figure out if you
are trying to boot a standard PC in that amount time or not. I don't
know your level of understanding in these matters so that's why I ask
for more information. I was the MIPS maintainer on RTAI for a couple
of years, and we had a very wimpy MIPS board and it would boot up and
start our application in about 2 seconds. Now, with the kernel
executing in place that time was significantly lower but ROM access
was very slow and this affected realtime performance. That's why I had
to go with copying the kernel to RAM. If I recall it would boot up in
under a second, but that's significantly more time than the 50ms you
are asking about.
On the other hand that really was a weak chip. 66MHz VR4181. Ugh. We
mainly wanted it for the low power draw.
Gilles pointed out that you could start a kernel based xenomai
application fairly early but userspace support takes more time to get
up. If you really want to get a fast boot time then try to link your
kernel to execute in place if the hardware supports it.
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