t is 30 years since the Commodore 64 went on sale to the public. The machine was hugely successful for its time, helping to encourage personal computing, popularise video games and pioneer homemade computer-created music. The $595 (£399) device took its name from its US maker, Commodore International, and the fact it had 64 kilobytes of RAM memory. The firm noted that made it substantially cheaper than other personal computers on the market offered by IBM, Apple and Atari. Commodore highlighted the fact that since it had designed and manufactured its own chips it had been able keep costs down - and the advantage helped it become the best-selling model in North America. In Europe it faced competition from two cheaper eight-bit rivals released over the previous year: the BBC Micro and Sinclair Spectrum. The Commodore's ability to display 16 colours, smoothly scroll graphics and play back music through its superior SID (sound interface device) chip - even while loading programs off tape - helped win over fans, but it did not become the market leader until the late 1980s. Debates continue to this day about which was the superior system - but what would today's youth make of the C64? BBC News invited Commodore enthusiast Mat Allen to show schoolchildren his carefully preserved computer, at a primary school and secondary school in London.