Symbolics was a maker of Lisp Machines. They are still selling a software emulation running on DEC Alpha systems. The emulation is called OpenGenera.
The operating system is called GeneraOs. Genera is completely written in Lisp - networking, graphics, device drivers, applications - everything. Some systems are still running on the Internet. The operating system provides for example TCP/IP, DNS client and server, mail client and server, X11, and many more Internet-based services. In fact the company Symbolics was the first organization ever to have a domain name - symbolics.com in 1985. A popular application is CL-HTTP, a web server written in Common Lisp. The author of CL-HTTP is John Mallery from the MIT AI Lab.
There was another operating system for Symbolics' Lisp Machines called Minima. It was developed for real-time systems like AT&T's ATM switches.
Symbolics built their own microprocessor - the Ivory - specially optimized to run Lisp software. Ivory-based machines were for example:
XL400, a workstation with a VME bus and a megapixel console with mouse.
XL1200, a workstation with a VME bus and a megapixel console with mouse. Symbolics also created high-end graphics cards for the XL1200 called FrameThrower?.
XL1201, a pizza box workstation with megapixel console.