Wailing and Gnashing of Teeth

There’s a reason you should take information found on the internet with a grain of salt. While researching citations for the CLIPS wikipedia article, I came across this post on the comp.lang.lisp group:

Look around on the net for CLIPS. I think it ports to Common Lisp fairly easily, but I could be wrong about that.

CLIPS is basically a free version of ART*Inference, which was the Automated Reasoning Tool developed by Inference Corporation. Inference, however, did some things that seem, in hindsight, to indicate terminal stupidity. They had NASA as a client, and NASA developed mission-critical software using ART (IIRC it had something to do with the shuttle’s landing gear deployment system). But Inference formed a partnership with Sun and quit providing DOS/Windows versions of their software. Meanwhile NASA had a budget office to satisfy and had to buy all their computers from the same low-bid source, which meant they could only get Intel-compatible machines.

This resulted in NASA having mission-critical software written in a language that was only available on the computers they weren't allowed to buy. After a certain amount of wailing and gnashing of teeth, what it boiled down to was that they were legally able to hire programmers to implement the language on “standard” hardware, but they weren't legally able to buy the “nonstandard” hardware. Within a few months they had enough of the language running to handle their mission-critical software, and as a taxpayer-sponsored effort, it was released to the public.

This put Inference between a rock and a hard place, since a free version of their main product, which ran on much cheaper hardware than their partner would allow theirs to, was now available.

I love this post. It’s more fiction than fact, yet the manner in which it’s stated and specific details give it an air of credibility. The part about the shuttle landing gear deployment system is implausible for a number of reasons, but certainly makes the origin story so much more dramatic. Oh my, if we can’t deploy our landing gear expert system, the shuttle pilot will never know when to flip the landing gear switch. Wailing and gnashing of teeth, indeed!

A subsequent post in the thread corrects many of the inaccuracies relating to ART, but echoes a similar explanation for the origin of CLIPS:

In the mid-80's, NASA decided to fly expert systems, particularly on the space shuttle, and required a system that would run on PC's or some other kind of tiny embedded machines, which had memory limitations at the point that were fairly tough for a lisp-based system (remember 640K limits?). 

The actual origin of CLIPS is disappointingly mundane. There was no directive from the highest echelons of NASA management to create a tool for deploying mission critical shuttle software. CLIPS started as a small internal project at the Johnson Space Center in just one of several groups working with artificial intelligence. It was originally conceived as an intermediate step between the existing commercial tools and a low cost replacement tool that could promote widespread use of expert system technology. As events transpired, in addition to being an intermediate step, CLIPS ended up being the replacement tool as well.

ART was a powerful tool, but it was also expensive, costing tens of thousands of dollars. You could buy a copy of CLIPS for $250 and install it on every computer in your organization. Placing expert system technology on as many computers as possible was the real motivation behind the development of CLIPS.