Well, I've done a little research on M-Systems' web page, and the DiskOnChip (DoC) sounds quite intriguing. It appears to load its own BIOS hooks, like a SCSI or UDMA66 controller does, so it doesn't use the IDE interface at all nor does it require (or pay attention to) any kind of configuration settings in the BIOS.
The doc file for the utilities, available at http://www.m-sys.com/drivers.asp?PID=2&FAM=doc&FILE=doc2k (as per Hardware1's Start Here post), tells all about how to format and set up the chip including a setting to force it as the first hard drive letter in a system with other mass storage, which is most likely the reason IDE drives often seem not to boot on the WebSurfer with the DoC in place (besides conflicts with a still-enabled onboard IDE interface). I would assume that booting from a floppy and running this utility to change that option would allow booting from a hard drive and still accessing the DoC as the last drive letter. Useful, eh?
According to M-Systems' info pages, the chip has the same pinout as any other bootable EEPROM, which leads me to assume (I'll find out tonight :) that it could be plugged into the EEPROM socket on a NIC and used to boot an otherwise diskless workstation of any kind! Could be useful for folks who want an X term box or NAT server or something of the like, but don't want to use the WebSurfer itself or an IOpener with its built-in flash.
Also according to M-Systems' claims, the flash technology's recycling algorithm makes it the longest-lived flash technology possible, and says that you could write to the flash continuously (their example uses 5Kb per minute every day) and it would still last over 2000 years! They even say you can use it for a swap file.
The utilities even include small image creation and restoration utilities. I don't know if these are specific to the DoC, or could create and restore images for any media. Might find that out over the weekend, too. But, at least it's useful so you can create a backup image of the DoC before you go messing with it ;)
All in all, it's pretty interesting stuff, and while I don't intend to use the DoC in my WebSurfer (I'll be putting in a nice, big hard drive for MP3's), I might be able to make use of it in my NAT server and quiet it down a bit by getting rid of the hard drive.
If anyone else has any more info on the DoC, post it to this thread so we can try and keep it in one place.