I've written some games and apps for the Acorn platform back in the day (Still have my A3010 in the loft) and I'd be happy to see RiscOS running on the Raspberry PI for more than just nostalgic reasons. For one BBC Basic is a truly excellent programming language to learn with (not to mention how fast it is for an interpreted language due to fitting into a small cache and general good design) - but there are advantages to the GUI as well. It made learning Windows very easy for me when the companies I was working for became a little larger than 4th Dimension and the Acorn went into the cupboard. These days I use Visual Studio on Win 7 along with other big meaty dev tools - and for Playstation and phone development I wouldn't consider anything else. Macs are insufficient for console development and linux simply wouldn't cut it at all. Not to say those systems don't have their place and for certain types of users. (architects and hobbyists respectively ;-p )But again - it doesn't matter what you end up using - RiscOS is a good universal example for both understanding GUIs and for learning how to program.
RiscOS, along with the BBC Micro, is what gave me the impetus and tools I needed to get into games coding. And of course, it really is a joy to use on a low powered machine. Debian is not a joy. Some people have mentioned memory protection and preemptive multitasking as problems - these are complete misdirect arguments. Did you ever boot up an Arc and think to yourself whilst running !Edit, !Paint, !Artworks and everything else you could cram into 2 Meg - "oh no, I wish this multitasking was pre-emptive!". Utter tosh. The raspberry pi can be rebooted in moments should things go wrong but my A3010 was very stable for coding, art and all the rest thanks - I think this is a non-argument. If the pi was 10 times more powerful, with lots of threads and a gigantic app catalogue of multitasking software then fine, you might be on to something in terms of those missing features. But for school kids? Nah.
Moreover Linux is a truly, utterly awful operating system to use as an educational tool, the purpose of Raspberry Pi. Perhaps the X Windows front ends are suitable, (though Debian seems dog slow on my Pi) but it's incredibly hard to communicate to Linux fans just how poor the command line syntax is for beginners. Or anyone. Yes - it's very powerful, but it's very opaque. I reckon that power would be handy 0.01 percent of the time for most people in most of their normal usage scenarios - and this includes what I do for a living. I use 3D and 2D tools for making art for games, I write commercial console engines, create and edit sound effects, make game design tools and download por, er, surf the internet for information - I never find myself missing powerful command line capabilities. It's 2012 - real apps have front-ends these days gentlemen. And run on Windows 7. I think it's laughable to suggest Linux shell stuff is suitable for education - if a bash shell was the only thing available on raspberry pi it would act as a solid brick wall, preventing the majority getting any further. This project would be dead on its first day.
Now for a contentious argument. Nobody uses Linux for anything. Yes, it underlies all sorts of things, from the 800,000 android phones unlocked each day to massive server farms - but nobody actually *uses* it. I use Ice Cream Sandwich on my phone - which I program using Visual Studio and C - or Java if I want it to run slowly - I never have to touch the linux substructure at all. Nor would I want to - I want to make spaceships explode on screen, not grapple with the command line. Now of course your mileage may vary - but I'm pretty sure these days computers come with graphical user interfaces. You know, sprites and whatnot. Children will want to write games for those graphical systems such as their smartphones. RiscOS is therefore a good choice as a windows like environment which will still allow the curious to grapple with coding and experimentation without hitting the sudo wall, and which will run in a tiny footprint in a way that Debian et al do not.
But the best thing about the Pi? None of the above opinions matter. It doesn't matter how wrong I am. You can just swap out your SD card and boot up Debian, or perhaps Ubuntu at some point or whatever flavour of OS you prefer, when more become available.
Anyway - when is RiscOS coming to the Pi?
Cheers,
Robin Jubber
CTO, Futurlab
http://www.velocitygame.co.uk/
P.S. This isn't a hate-on for Linux. Debian seems a good way to get Java (for learning), OpenGL (for pretty graphics) and C (for actually doing stuff) up and running in a GUI environment. On a 20 quid computer? Can't grumble.