The Coding Placeholder 'Foo' Started in a 1930s Fireman Comic Before MIT's Model Railroad Club Adopted It

The RFC was written by Donald Eastlake 3rd, Carl-Uno Manros and Eric Raymond, and it starts with a count. “Approximately 212 RFCs, or about 7% of RFCs issued so far, starting with [RFC269], contain the terms foo', bar’, or `foobar’.” RFC 269 dates to December 1971.

Then it goes back further. “The earliest documented uses were in the surrealist “Smokey Stover” comic strip by Bill Holman about a fireman.” The strip had its own vehicle: “Holman’s strip featured a firetruck called the Foomobile that rode on two wheels.” As for where the word itself came from, “Holman claimed to have found the word “foo” on the bottom of a Chinese figurine.” The RFC says the strip “appeared in various American comics including “Everybody’s” between about 1930 and 1952.”

The word took a detour through World War II. “In 1944-45, the term `foo fighters’ [FF] was in use by radar operators for the kind of mysterious or spurious trace” that later got the name UFO. The RFC notes the phrase came back in 1995 as the name of a band.

At MIT, the Tech Model Railroad Club’s 1959 “Dictionary of the TMRC Language” gave the word a mock-solemn entry: “Foo: The sacred syllable (FOO MANI PADME HUM); to be spoken only when under obligation to commune with the Deity.” From there it was “probably originally propagated through DECsystem manuals by Digital Equipment Corporation (DEC) in 1960s and early 1970s.”

The pairing with bar has a different story. “When used in connection with `bar’ it is generally traced to the WW II era Army slang acronym FUBAR,” which the RFC spells out and this piece won’t.

The RFC counted RFCs through 2001. The number of specs, docs and code samples that have used foo since then is much larger, and nobody has redone the count.