If you haven’t heard of John McCarthy, you’re probably learning about his many important contributions now. Some examples:
- He’s the inventor of Lisp, the second-oldest high-level programming language, younger than Fortran by just one year. Lisp is one of the most influential programming languages in history. Granted, however, most programmers don’t use directly Lisp-based languages, so its great influence has been mostly indirect.
- He coined the term “artificial intelligence.” Granted, however, AI has got a bad rap from being oversold by enthusiasts like Minsky; for the past 20 years or so it’s been safer to talk in euphemisms like “expert systems.” So here too McCarthy’s great influence has been less direct.
- He developed the idea of time-sharing, the first step toward multitasking. Okay, now we’re talking about a contribution that’s pretty directly influential to our modern systems and lives.
But perhaps McCarthy’s most important single contribution to modern computer science is still something else, yet another major technology you won’t hear nearly enough about as being his invention:
Automatic garbage collection. Which he invented circa 1959.
No, really, that’s not a typo: 1959. For context, that year’s first quarter alone saw the beginning of the space age as Sputnik 1 came down at the end of its three-month orbit; Fidel Castro take Cuba; Walt Disney release Sleeping Beauty; The Day the Music Died; the first Barbie doll; and President Eisenhower signing a bill to enable Hawaii to become a state.
GC is ancient. Electronic computers with core memory were still something of a novelty (RAM didn’t show up until a decade or so later), machine memory was measured in scant kilobytes, and McCarthy was already managing those tiny memories with automatic garbage collection.
I’ve encountered people who think GC was invented by Java in 1995. It was actually invented more than half a century ago, when our industry barely even existed.
And here’s hoping we can take a break for a while from writing these memorials to our giants.