From Steven Levy’s Hackers: Heroes of the Computer Revolution (Penguin Books: 2001): 43:
[Peter Samson, one of the first MIT hackers], though, was particularly obscure in refusing to add comments to his source code explaining what he was doing at a given time. One well-distributed program Samson wrote went on for hundreds of assembly language instructions, with only one comment beside an instruction which contained the number 1750. The comment was RIPJSB, and people racked their brains about its meaning until someone figured out that 1750 was the year Bach died, and that Samson had written an abbreviation for Rest In Peace Johann Sebastian Bach.