What does Halt and Catch Fire mean?
In these, the waning days of Mad Men, AMC has got itself a new television program about nostalgia and a reckless, dangerous creative type who interprets rules and regulations like a Disney pirate tricking a girl onto his ship. (And, to be perfectly clear, by “ship” we mean “penis.”)
Entitled Halt and Catch Fire, the show takes place in 1983, or just far back enough for us to know that computers were going to be Kind Of A Big Deal, but before we knew exactly how big a deal. The show itself is most definitely a Big Deal for its creators, Christopher S. Rogers (whose credits include, well, the show he currently works on) and Christopher Cantwell (best known for this movie, which, to widespread public disappointment, is not a documentary about this guy).
The pilot aired on June 1st, and has gotten decent reviews: the Onion A/V Club calls the episode “promising” and says it “moves with a kind of confidence it’s hard to fake;” the Washington Post, in a general overview, notes the current crowded field of TV shows about technology and / or nostalgia for the recent past.
But one thing neither the reviews nor the show’s promotional materials do much to explain is the title. “Halt and Catch Fire.” It’s a terrifically arresting phrase, to be sure: it grabs the ear and whispers into it. It sounds rather like a coded message espionage agents might use to describe a situation gone to hell in a handbasket: “Kangaroo, this is Stevedore. Halt and catch fire. Repeat: Halt and catch fire. The hull has been breached. Abandon spaceport.” Along with other such espionage-y language.
So: does it actually describe anything like that? What does Halt and Catch Fire mean?
Well, no; it doesn’t mean that. In keeping with the show’s setting and content, the phrase “Halt and Catch Fire” actually refers to “machine code instructions that cause a computer’s CPU to cease meaningful function” (thanks, Wikipedia). Practically speaking, the “Halt and Catch Fire” (or HCF) command is used for various CPU tests, since, once the command has been executed, the computer won’t respond to any other commands, and has to be restarted in order to be used normally:
[The command] makes the processor enter a mode in which it continuously performs memory read cycles from successive addresses, with no intervening instruction fetches. The address bus effectively becomes a counter, allowing the operation of all address lines to be quickly verified.
Of course, if you understand all of that, you probably knew what “Halt and Catch Fire” meant in the first place, and have spent the last few days pointing out any technical inaccuracies of the pilot episode on AMC’s forums.
But that part of the explanation only covers the “Halt” of the title. The other part, “Catch Fire,” refers to the idea that the computer, when in this state, could run fast enough to melt its circuitry. This is something that has only ever happened apocryphally, but that fact should in no way detract from your ability to envision a giant room full of giant, early-80s, Wargames-style processors, all going up in flames while a madman cackles in their midst.