The BBC Microcomputer System—also known as the BBC Micro or affectionately the “Beeb”—was a series of microcomputers designed and built by the Acorn Computer company for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation. The BBC Micro was hugely successful in the UK, selling over 1.5 million units, and was widely used in schools across the UK.
b2 is a cross-platform BBC Micro emulator. While the emulator’s interface is rather fiddly, and misses a few features, the emulation is excellent.