You can use a read-only file system. With an embedded system, you don't have that much to deal with. You can strip the kernel down to almost bare, and compile everything you need into the kernel itself; vs a modular kernel. Once you get it to boot, it will always boot, no matter how many times power is cut.
I'll tell you a little trick. I don't know how much disk you need, but linux will USB boot off up to a 4 GB flash drive. If you know what you're doing, you can go up to an 8 GB flash drive. That way you can configure the drive on a fully functional linux system, with every tool you could ever possibly want, and then plug it in the embedded device, and watch it go. It's cool.
There are embedded distros, that are made to just put on a flash drive, as read only. Read-only is a file system flag. You can set it with 'parted'.
Last edited by AwesomeMachine; 02-23-2009 at 01:13 AM.