Booting FreeDOS using disk-on-chip

There was a discussion on the FreeDOS mailing list about booting FreeDOS using a disk-on-chip device.

I want to know if it's possible to install FreeDOS onto a flash RAM/ROM (like ROMDOS) on a Single Board Computer and where I can read about such.


Bart Oldeman writes:

Not out of the box, as there is a tiny bit of code that modifies the code segment (here also self-modifying code), like in intr.asm. But with some source code tinkering it should be possible. I don't know whether anybody has done it before or not.

I'll be glad to hear if you or someone else succeeds and would be interested to hear what you needed to change. I have no experience at all with ROMmable things in this way.


Jim Hall writes:

Hmm... I had thought that someone had already done this. I suppose there's a technote about it on the web site - the 'search' box on the web site should find it.

The DiskOnChip is a flashdisk device that looks (to the OS) like a hard disk. I don't have a DOC, but I seem to recall getting email from embedded developers who have booted FreeDOS from a DOC. [...]

I wasn't able to find any help on the FreeDOS site, but that just could be that I'm using a different search term. Anyway, I did some searches using Google. Some good results from what I found (excerpts):

Linux Based Diskless Workstations
[...] Some PCs, particularly single board PCs and smaller PCs intended for embedded applications include a socket for a Disk-on-Chip chip. These are available in various sizes from approximately 4MB up to about 32MB. They appear to the BIOS as another disk, and thus fairly standard disk-booting methods can be used. The approach often taken is to boot a version of DOS (eg, FreeDOS), and then use syslinux or loadlin or similar to boot from DOS into another operating system. [...]

Technical Details On PUMP II
PUMP II is hardware that allows for decoding and playback of MP3 audio files without any additional hardware. [...] PUMP II is based on the i386EX processor around which the other components are arranged. A free DOS clone, FreeDOS, serves as Operating System. [...] The BIOS is a custom development and supports Flash-ROM as well as CD-ROM and hard disks.
This site also lists some flash disk technical specs - nice surprise to find a company doing FreeDOS stuff!

Linux Router message board
This includes information for setting up a Linux-based router using DOC and FreeDOS as a workaround to boot into Linux.

So I'd guess it's looking pretty good already. That last one about the Linux Router Project (LRP) is interesting, since they just say to format the entire DOC as a DOS partition, and use FreeDOS. No changes seem necessary - at least, not by that page.