Monday, February 14, 2011

Mabel The Swimming Wonder Monkey, or The Great Dead Monkey Project

DEC VAX 11/780
Okay, so, this story seems to vary wildly from one source to the other, so I have no idea how much is true and how much is urban legend. But there's no way in hell I'm passing up the opportunity to write a post about The Great Dead Monkey Project, so here goes:

They say Mabel was a monkey, maybe a chimpanzee, trained by scientists at the University of Toronto in the late '70s. They called her Mabel The Swimming Wonder Monkey  because they'd taught her how to swim underwater; she could breathe with a kind of scuba system. The researchers would pump in various gasses to determine the kind of effects they had on her body. 

The whole system was controlled by an early computer—the DEC VAX-11/780. It was a brand new, state of the art machine which took up most of a room, cost hundreds of thousands of dollars and came with up to 2 MB of memory. But the one the researchers at U of T were using had developed some kind of problem, so one day, while Mabel was in the pool, a technician came in to fix it. And while he was working on it, he accidentally screwed with part of the system regulating Mabel's air. The Swimming Wonder Monkey drowned.

Her death, according to a dictionary of computer geek slang, is how they got the term "scratch monkey"—an extra drive used to back-up data while troubleshooting. Apparently it's a common expression for safety-conscious computer folk: "Always mount a scratch monkey". If they'd done that at U of T, their monkey wouldn't have died.

There's another version of the story out there as well. It comes from someone who claims to have interviewed the woman who programmed the computer. According to her, the experiment had nothing to do with swimming underwater, but involved five monkeys who were hooked up to the computer so that it could read their brain waves. When the DEC VAX-11/780 was being worked on, it supposedly accidentally sent out electrical signals, directly into the monkeys' brains. It killed three and stunned the other two. The experiment became known as The Great Dead Monkey Project.


I was tipped off to this one by a couple of friends who run the Once Again, to Zelda blog and are editors with me over at the Little Red Umbrella and who were trying to figure out why an ad for a "Toronto Bucket List" with a photo of a chimpanzee in a wetsuit kept showing up in the sidebar of their Facebook feeds. Which is still confusing. You can read the online dictionary's version of the story here, and The Great Dead Monkey Project version here. Also, coincidentally, there's a monkey gargoyle at U of T, on one of the doorways to University College, which you can see a photo of here.


  1. It appears I entered this on the wrong page, so I'll try again here.

    Both stories seem highly suspect.

    The VAX 11/780 came out in late 1977, and I don’t believe the first one arrived at UofT until some time later. Looking for references from the era, it appears they didn’t have one until the early 1980s. UWatterloo, often on the forefront of computer tech in this period, didn’t get their first VAX until 1981, if I'm reading the history correctly.

    But more questionable is the use of a VAX for this sort of thing. The VAX-11 was so-named because it was designed as a follow-on to another DEC product, the PDP-11. The PDP-11 was, in turn, a major development of an earlier machine, the PDP-8.

    I mention this because the PDP-8 was one of the first computers that was widely used as a generic number cruncher in many science experiments. It was so successful in this role that a number of companies started producing systems aimed specifically at this niche. Perhaps most popular among them was the Data General Nova system. The Nova cost about $8000 in a basic version, and had all sorts of places you could hook in test equipment.

    For instance, here's an image of the world's first CAT scanner:

    On the far right you’ll see a white-ish coloured box on the rack with a bunch of buttons on it. Right above that is a much darker box. That box is a Nova. Now you have to imagine the amount of number crunching that goes into making a CAT scan… if the Nova can do THAT, trust me, it can do anything being described in this article. In its sleep.

    Now the Nova was basically a PDP-8. The PDP-11 built on that to make a machine that could handle more devices, like disk drives and such. The VAX-11 took that into the 32-bit world, which is needed for handling large accounting files and such. So while the PDP-8 and Nova were used right into the 1980s for science experiments, the PDP-11 was rare, and I've never heard a single case where the VAX was used in this role. It simply wasn't designed for this, and far too expensive.

    So, basically, I call BS. It's possible the original author was confusing several machines, perhaps the PDP-11, but even then it seems unlikely.

  2. Hmmm, it looks like some crow eating might be in order. In fact, there was a PDP-11, and that was the problem. It seems they were using 11/05's to collect data, which was then fed to a 11/44 for writing to disk. Someone else, in a different department, wanted that ported to their new VAX (god knows why) and that's where the bug came in, because they eliminated the 11/05's as front-ends. It was directly connected, so it was possible to write directly to the electrodes.

    Also interesting is the spin-off, which seems to suggest that a later machine was the one where Henry Spencer wrote cnews. I'll have to ask him if its the same machine.

    1. Thanks for taking the time to share all that!