Editing PDP-1 (section)

==Computer music==
MIT hackers also used the PDP-1 for playing music in four-part harmony, using some special hardware – four [[Flip-flop (electronics)|flip-flop]]s directly controlled by the processor (the audio signal is filtered with simple [[RC filter]]s). Music was prepared via [[Peter Samson]]'s ''[[Harmony Compiler]]'', a sophisticated text-based program with some features specifically oriented toward the efficient coding of [[baroque music]]. Several hours of music were prepared for it, including Bach [[fugue]]s, all of Mozart's ''[[Eine kleine Nachtmusik]]'', the ''[[Ode to Joy]]'' movement concluding Beethoven's [[Symphony No. 9 (Beethoven)|''Symphony No. 9'']], Christmas carols, and numerous popular songs.