Memory usage

[Aaron J. Grier]

On Thu, Jul 22, 2004 at 08:28:35AM -0400, Etienne Fortin wrote:
> Doing my homeworks... It seems a little rude, I don't want anyone to
> do my homework, I can do them myself. I just want to hear from the
> experiences of others...

I'll quote myself here:

> > have you tried it?
> > 
> > is it enough?
> > 
> > what numbers come from sptests/spsize?

the spsize test is going to give you the most useful information.  I
urge you to run it on whatever evaluation target you currently have
available.  it will tell you how much memory is required for RTEMS and
its objects (timers, tasks, semaphores, etc).

you will also need to start writing some device drivers to see how large
they are.  our device drivers use anywhere from 4 bytes to 1KB of
data/bss.

there are exceptions to every rule in the embedded world, and you won't
know what's possible until you do it.

see if you can strip down your API requirements.  can you use the rtems
classic API instead of posix?  can you avoid libc entirely?  how much
stack do you need per task?

-- 
  Aaron J. Grier  |   Frye Electronics, Tigard, OR   |  aaron at frye.com