At 12:23 12/05/99 +1000, Graham Stoney wrote:
>Hi Folks,
>
>I'm currently investigating options for a minimal-cost x386 based diskless
>embedded controller running a stripped-down Linux kernel for a reasonably
>simple embedded TCP/IP application. I'm very interested in opinions or
>experience anyone could offer.
I'm afraid I do not exactly answer to your question, but this may help : It
depends on what you call minimum :
If you have maybe 1 Mb Flash linear storage and 4 Mb RAM, you should use
2.0.36 Kernel, with ROMFs enabled, then, have a look at the romdisk patch
from Oliver Xymoron. This would allow you to embbed a really small root
filesystem of your own into a device driver built into the kernel. This is
prolly not the smallest possible, but it's easy. You should set this up in
less than a few hours.
If you need a shell, use ash. If you need an TCP/IP basic client, check nc
from Hobbit. Check tomsRTBT from www.toms.net for good ideas about how to
shrink linux utilies.
However, using a read-only root fs is not so easy with Linux.
>My choice of x386 is to allow easy hardware & software prototyping on desktop
>PC's and off-the-shelf embedded biscuit-PC-like boards. Ultimately, I'd
like to
>build a tiny BIOS-less system with traditional (i.e. non-IDE) flash/eprom
>memory and minimal RAM. Since the Linux kernel has a larger footprint than
>traditional embedded OS's, it would be nice to run it directly from ROM with
>a ROM-based root filesystem. I'd prefer not to simply copy the kernel into
RAM
>or use an "initrd" RAM-disk for root filesystem stuff which is all
essentially
>read-only. Demonstrating that Linux can run embedded with very little RAM is
>one of the goals here, even at the expense of slightly more ROM.
>
>My guess is that much of the specifics here can be handled by a ROM-based
>bootloader which sets up the x386 MMU to effectively "load" the kernel, and
>from then on everything is much like running in a desktop box, albeit a
>severely stripped one. Does anyone know of an existing bootloader that can
>perform this sort of magic, or any other pointers to existing solutions?
>
>Thank you,
>Graham
>
>
Pierre MONDIE : SSR : 74-78
