Something that I've been thinking about for a while, which has come up on this thread a few times, is that the Pi will be booting Linux, and, relative to the good ol' days of the BBC etc, that's complicated. Easy to use or not, it's the fact that the level of complexity of a modern OS, be it Linux, Mac OS, Windows, is massive. On the beeb, you typed "AUTO", and started typing your program in. You could type *MEM. (with an extension ROM, I think, it's been a long time), and see your program in memory. You could create some assembler that compiled to a particular address in memory, and then look at that bit of memory and see the machine code, run it, and see the data bits in memory changing.
What I'm getting is that it was possible to actually see what was going on, which, under any modern OS, it isn't, really - you've got protection levels, virtual addressing, and all sorts of other stuff that I don't even pretend to understand.
So, with the RPi, is there an opportunity to use the fact that there's a single processor, architecture and hardware, and create a really simple OS, that just boots straight to a some form of prompt. No multitasking, everything running in kernel mode (if that's even possible), so everything is visible. Straight memory addressing, maybe only allow a small amount, say 1Mb - 0x00000 to 0xFFFFFF. Create a program in a similar way to the beeb - ignore the language for now, it's just "a program". Memory dumps under another command, and you can see your program in memory. If the program could then get the address of a variable somehow, then you could look at that bit of the memory before and after "running" the program.
Ok, so it doesn't have the "wow"/"cool" factor that kids might need to draw them in, but being completely in control, and being able to see everything going on was one of the things that really got me interested as a kid. Plus I think once you've wowed them with the openGL demos and maybe a pygame demo that they can mess about with and change a bit, then maybe they want to understand a bit more about what's going on.
Something along the lines of a cut-down minix (obviously ported to ARM)? I'm no OS expert, so I don't know whether it would be feasible or not, or how tricky and involved it would be, or maybe someone knows of something that exists already/will soon exist?
Or am I dreaming, and it would be easier to emulate under Linux?
Aging BBC Micro fan.