how to port linux to pc104?

No port required. Most PC104 is pc-compatible.

Unless you are running diskless, which is more involved.

But the fact it's a PC104 form factor shouldn't enter into it.

Rufus

Try

I have a page on how I did it.

pc104 is only a form factor. it's irrelevant to porting.

I told you this already

Rufus

It's like a PC with a ISA bus tough the signal electrical drive is lower.

You might want to try an embedded distribution or Linux From Scratch to allow for a very minimal system. I had a PC104 system running Linux 2.4 kernelC, C++ glibc libraries, boot scripts, basic configuration/admin tools, telnet+ftp and it fitted under 8 megabytes.

Some makers also provide pre-built Linux distributions

With a cheap 32MB CompactFlash, you've got plenty of space for your application. The CF emulates an IDE harddisk but it is slower. Linux will think it is a standard hard drive. Just make sure you do everything to avoid writing to the compactflash (disable swapping, write temp stuff to a ram drive, disable logging or points log file to a ram drive). Unlike hard disk, flash memories wears out.

Most PC/104 can also redirect BIOS output to a serial port. You can also use a serial port as the Linux console. The CPU is x86 compatible but often have extras digital I/O pins and A/D D/A converters. Just watch out for max source/sink currents. You can sometime access these using direct I/O port when running as root or you use a kernel driver. The PC104 maker often provides kernel patch/drivers for extra functionality.

Some PC/104 also have Disk-on-Chip

DoC requires the Linux MTD driver & boot loader support. I've never used them. I think DoC are better than CF for industrial or long-term use. CF are probably lower quality as they are sold for consumer devices like cameras. The physical C.H.S. of the CF varies among brand. The actual capacity is always a nominal value. CF are cool as you can hook them to a USB CF reader for less than 20$ on your Linux workstation. When the board won't boot; you can fix things on your workstation. Believe me, it helps at lot.

Simon Paradis simon _dot_ paradis _at_ usherbrooke _dot_ ca