Re: Linux on 386 EX SBC Card

christophe leroy (christophe.leroy5@capway.com)
Tue, 20 Oct 1998 19:10:03 MET


> From: Carlos Morgado <l39801@alfa.ist.utl.pt>
> Date: Mon, 19 Oct 1998 02:25:07 +0100
> Subject: Re: Linux on 386 EX SBC Card
>
>
> On Sun, Oct 18, 1998 at 05:09:57PM +0100, christophe leroy wrote:
> > I'm about to buy a 386 EX SBC Card from universal developers
> > (www.universal-developers.com).
> > This card has a Intel 386EX with 2Mbytes DRAM, 2 serial ports,
> > 1 paralele port, 1 interupts controler, 1 timer, 1 Watchdog timer
> > 1Mbytes flash PROM with BIOS and DOS in it.
> >
> this is for what ? embeded controlers ?

It is called "applications card"
>
> > Do you think I could run linux on it ?
>
> can't see why not ... :)
>
> > Do I need the BIOS, or can Linux do all initialisation alone ?
>
> Usually Linux uses the BIOS to boot (via lilo or some other thing) and to do
> some basic hardware detection. Since your hardware won't change you can
> hardcode it into the kernel. Also 1M ROM is large enough to fin an
> uncompressed kernel so you might do a autobooted kernel hack ehhe :)
>
I only need about 250K for a compressed kernel. Remaining 750K is for
a filesystem with compression (something i've developed around ROMFS)

> Now remember you will run some programs on it too no ? :)

Little programs, thats why I dont want to lose memory with ramdisk

>
> > Is there a driver to access ROM as a block device ? If not can I use
> > /dev/rom device MAJOR defined in devices.txt for my driver?
> >
>
> Hum there is a a ROM fs developed by the PDA port people i think. You might
> want to look into that.

ROMFS is a filesystem, not a block driver. It needs a block driver to
access ROM memory. And it has been called ROMFS because it's
readonly.

>
> Some time ago i asked around and the last kernels to run on such tight
> memory where 1.0. I was told someone did a patch for 2.0 to boot on a
> ridiculous amount of RAM.
>
> I would try to keep the kernel on ROM. That can be achieve with some
> sensible linker map .. to make the kernel live well with text on ROM and
> data on ROM.

I prefer kernel on RAM, files on ROM

>
> What exactly are you going to do with linux on this ? I'm curious eheh :)
> Does this have any way of talking to the world other then serial/parallel ?

It also has a PC/104, 8bits BUS (compatible with ISA)
Note that paralelle is useful for a zip drive (even if it doesnt
support EPP)

dims are 12.7 cm * 9.4 cm
I think about using it for a robot, or something like that.
Could also be used as a router and firewall on a slow link.
Also for the fun of making Linux run on every computer in the world.
Linux must run everywhere a Micro$oft OS runs

christophe

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