The names “Medley”, “Interlisp-D”, “”, “Common Lisp”, etc. are often used in confusing ways. We’re talking about a lot of different things that evolved over decades. These are cemented in by usage in different publications over time. We hope this glossary of terms will help.

Vocabulary and relationships

Alto Lisp
An (unsuccessful) attempt to build a Lisp-based OS for running Interlisp on an Alto
Carol, Fugue, Harmony, Intermezzo, Koto, Lyric, Medley
Named releases of Interlisp-D. All are obsolete except Medley.
Common Lisp
The subject of a 10-year standards process to converge multiple dialects of the Lisp language. Strong influences from many Lisp dialects, including Interlisp.
Common Lisp the Language
Book by Guy Steele with two editions:
  • CLtL1 – edition 1, 465 pages
  • CLtL2 – second edition, 1029 pages
Common Lisp dpANS
The ANSI Standard for Common Lisp

Starting with the Lyric release of Interlisp-D and then the Medley release, the implementation of Medley included implementations of Common Lisp (CLtL 1) as well as the Interlisp dialect in a single development environment; this was made possible by using the (Common Lisp) “package” feature to allow both dialects to be intermixed.

A compiled form of Medley Interlisp files.
By Warren Teitelman: a first attempt at building a “Display” (GUI) with Interlisp running on Maxc (A PDP-10 clone) a Xerox Alto as a graphics terminal connected to it via Ethernet.`
Dorado Lisp
The reimplementation of the AltoLisp microcode on the Dorado – a research prototype.
An obsolete named release of Interlisp-D.
An obsolete named release of Interlisp-D.
An obsolete named release of Interlisp-D.
A GitHub “organization” with ~20 repositories, see
Both a language and, in some cases, the implementation of that language. Usually used with some other wording or refinement
Interlisp: The Language and its usage
A book by Steve Kaisler which describes Interlisp of the 1970s & 80s
A “domain name”, used for some web sites and email addresses
The first implementation of “Interlisp” for the DEC PDP-10 / Tenex
Implemention of Interlisp for the IBM-360
What Dorado Lisp became. The D stood for both “Display” and “D-machine”. An implementation of
  • Interlisp the language
  • The Interlisp programming tools
  • A Graphical User interface to Interlisp programming development
  • A large number of tools, utilities, games, screen-savers
  • A Lisp-based operating system for D-machines which, when coupled with microcode implementation of a Virtual Machine, allowed the D-machines to operate as a personal workstation. Each D-machine had its own microcode with different configurations and micro-instructions.
Implementation of Interlisp for Digitial Equipment Corporation VAX systems
A California-registered non-profit organization (DBA Established August 2021. 501c3 EIN 87-2528093 California registered charity CT0278267. President Larry Masinter, Treasurer Ron Kaplan, Secretary Herb Jellinek.
An obsolete named releases of Interlisp-D.
Used as a file ending, xxx.lcom, for compiled Medley files.
An obsolete named releases of Interlisp-D.
The final named release of Interlisp-D.
Medley 1.0, Medley 2.01, Medley 3.5 numbered releases of Interlisp-D
At some point the name Interlisp-D was retired and Medley used to name the software.
An implementation of the functions of the microcode D-machine, but written in C for the Sun Microsystems (RISC-like) SPARC processor workstation, initially developed by Fuji Xerox. Subsequently ported to little-endian processors and other operating systems.
Structured Design Language
A file containing the saved state of Interlisp virtual memroy
The X Window System


Boston consultancy which (late 60s) implemented BBN Lisp and the Tenex operating system.
Xerox PARC or just PARC
Palo Alto Research Center, which continued in collaboration with BBN on (renamed) Interlisp. PARC developed the Alto and Dorado. Now part of SRI International.
SRI International
non-profit scientific R & D institute
Xerox Electro-Optical Systems (XEOS)
Xerox division supporting classified customers
Xerox Artificial Intelligence Systems (XAIS)
The division working to commercialize Xerox Workstations running Interlisp-D.
Rank Xerox
Xerox affiliate in charge of delivering Interlisp-D workstations in Europe
Fuji Xerox
Xerox affiliate – joint project of Rank Xerox and Fuji Photo Film company.
Company founded in 198x to take on the Lisp business from Xerox. Closed within 10 months and folded back to Xerox.
Smaller company, started by John Sybalsky; it had the license to create and distribute derivative works of Maiko and Medley Venue ceased operations… … some history …. Software recovered from late 90s…. Fuji Xerox worked with John into the 90s with ports and addons and other software….
Medley Interlisp Project
Began late 2010’s with Nick Briggs getting Maiko to run on MacOS. In earnest in 2020 with start of weekly Zoom meetings, getting it to run on Linux in a VM and getting the Interlisp and LispCore google groups and ….