Books of Note

Practical Common
LispThe best intro to start your journey. Excellent coverage of CLOS.

ANSI Common
LispAnother great starting point with a different focus.

Paradigms of Artificial Intelligence
ProgrammingA superb set of Lisp examples. Not just for the AI crowd.

Friday, July 16, 2004

Building a CADR? 

Today, I found a reference to the original MIT AI Memo 528 which describes the CADR Lisp machine. It would be interesting to rebuild this today using an FPGA. Not that I have the time for such a project, but given current FPGA densities, it would seem to be relatively easy to use a PCI-based FPGA evaluation platform to (re)create a Lisp machine. That would be kinda fun.

Update: I have gotten a few comments from people pointing out that AI Memo 528 is a scanned document and the current PDF at MIT is missing one of the pages. If you're actually up for trying to recreate this machine or study it in great detail, you'll need to do a bit of reverse engineering, it seems, to recreate the missing information. A few more people pointed out that you're still going to be stuck there with a CADR and no software. Okay, but it was an interesting idea, no? ;-)


There was a thread on a similar subject on the LispM-Hackers list (, wherein someone suggested the same thing for an Explorer I CPU. Note that there is a page missing from MIT AI Memory 528, so you would have to extrapolate this missing information, and that nobody has a full disk and ROM image set for the CADR.

Really, though, modern hardware should be more than fast enough to emulate the full system in software. And you'll need to do that first anyway simply to work the bugs out of your understanding of the design.

I've been searching everywhere for old CADR sources. I have some strong leads. If you're really serious about building an FPGA CADR, or, more likely, a CADR simulator, please get in touch.

I've been working on an l-machine simulator for the 3600's. It's coming along nicely. I'm about 35,000 instructions into the warm boot so far.


Would you consider this? Passing the Test? For over ten years, I have been working on a method of semantic interpretation that applies in any situation. Using this method, I believe that a software program can pass the Turing Test. The book, "How to Design a Universal Artificial Intelligence," is currently online, in its entirety, and I am requesting your review of this work. This is it; this is real; this is a working counterpart program.

My website

Post a Comment

Links to this post:

Create a Link

This page is powered by Blogger. Isn't yours?