What is a Lisp Machine?
Jack J. Coleman asked me what a Lisp Machine is, so here's my quick answer.
In the mid 1970s, MIT began looking at ways to run Lisp better. The approach they settled on was to create a computer capable of running Lisp more-or-less natively. It was a microcoded machine that could do the tagging operations and garbage collection in parallel with the main execution.
The operating system and all of the utilities were also written in Lisp.
Several companies then commercialized the Lisp Machine. Let's see, there was at least Symbolics, LMI, and Texas Instruments. Xerox also sold their own kind of Lisp Machine, but the hardware and software weren't based on MIT's design, as the others were.
These machines were very popular with the government and corporations experimenting with artificial intelligence (this was during the AI boom of the early to mid 1980s). For example, I worked closely with a group at American Express that had one of the more successful AI projects call Authorizer Assistant, which was an expert system (using ART, I believe) that made credit card authorization decisions. This was hosted on a series of Symbolics machines which were connected to Amex's IBM mainframes.
Anyway, in the late 80s, the AI boom went bust and unfortunately the market for the Lisp Machines went with it. All of the companies selling Lisp Machines either quit doing so, went bankrupt, or sold off the assests. Symbolics still exists today as a small operation to continue the maintenance contracts.
I've bought my Lisp Machine directly from Symbolics (I don't have it yet, it will be delivered on May 24th). It is a Symbolics XL1200, introduced in 1989. By today's standards, it is a slow machine, however, if you get a chance to view the Lisp Machine videos on Rainer Joswig's site (unfortunately seems to be down for a while), you'll see that the speed of the development environment is still competitive with today's systems.
Some great links on Lisp Machines, especially the Symbolics kinds are:
Ralf Möller's Symbolics Lisp Machine Museum
Peter Paine's site
François-René Rideau's site.
Supposedly some other Lisp Machine movies are on CLiki's page on Lisp Machine Videos and on the original Lisp blog, John Wiseman's great Lemonodor site (here and here).
On a future post, I'll explain why I want a Lisp Machine, and what I plan on doing with it.