The Raspberry Pi received a RAM boost recently, but it certainly won't need it to run the latest officially supported operating system -- RISC OS. A far cry from Linux variants the naked board is used to, RISC OS was developed in the late eighties by the same hotshots who designed the first ARM processor. Fittingly, it's also related to the OS found on the BBC Micro, a computer that shared the Raspberry Pi's educational vision. Don't expect much from the simple OS, but it will run extremely fast given the Pi's hardware is practically futuristic compared with the computers it was intended for. The simplicity does mean, however, that it's much easier to get right into the system and start tinkering. It was formerly a closed-source OS, so luckily, there are a bunch of Programmers' Reference Manuals (PRMs) available to kick-start your next project. Whether you are totally new to RISC OS, or excited to dive in for nostalgia's sake, head to the source link for everything you'll need.