Now woefully
defunct maker of a fine line of
Lisp Machines. Symbolics, Inc., went officially
bankrupt in 1996. Before that, they existed as a company but probably hadn't manufactured a
computer since the late 1980s -- they just had a tiny
staff and a
warehouse of parts. These machines continued to be used by some companies and research organizations, in some cases well past 1995, despite the fact that by that time they were
slow and
getting on in years. There just wasn't anything else like them.
Symbolics lisp machines were microcoded and used a 36-bit word in a tagged architecture. It was basically a 32-bit machine, and the extra 4 bits were used for datatype tagging, so there was hardware support for some runtime type-checking.
Symbolics machines ran their own operating system, called Genera, which fully integrated a wonderful LISP development environment. (Aside: at one point Genera was ported to the DEC Alpha as "Open Genera", but this never caught on as well as it should have.) All system software and almost all bundled applications were written in Symbolics Common Lisp. Symbolics machines came with Zmacs, a dialect of emacs. Symbolics keyboards had some interesting keys -- the expected shift and control keys, but also keys labeled "meta", "super", and "hyper". Sometimes you would have to hold a strange combination of these down, and click with the mouse, or strike another key, to do what you wanted to do. The Symbolics keyboard also had an "Abort" key, which would bail you out of whatever error break you happened to be in.
The development environment had some interesting properties, one of which was the ability to reinvoke program execution from a previous point in the stack, after having compiled a new version of the function that caused the error that made execution stop. Another nice feature was that all of the outputs to the console were mouse-accessible pointers to the actual objects, so if a reference to some complicated structure had printed on the screen, you could use the mouse to grab it and insert it into a form that you were typing.