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The Medley Interlisp Project
@interlisp.org
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Official account of the open source project to preserve, revive, and modernize Medley Interlisp. This extensible graphical operating and programming environment has roots in Xerox's Palo Alto Research Center (PARC).

https://interlisp.org
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interlisp.org
The Medley Interlisp Project @interlisp.org · Dec 12
Hello from the Medley Interlisp Project! We revive and modernize the Medley Interlisp extensible graphical operating and programming environment created at Xerox PARC.

interlisp.org

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Screenshot of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and several windows with a white background and a title bar with white text on a black background. The windows display text, bitmaps, graphs, icons, sketches, and other graphical documents and elements.
interlisp.org
Modern Medley Interlisp provides support for the system clipboard as described in the linked documentation page.

The Meta key is usually the Alt key or equivalent on modern systems. Clipboard support requires the xclip program on Linux.

files.interlisp.org/medley/libra...

#interlisp #lisp
files.interlisp.org
February 17, 2026 at 11:03 AM
interlisp.org
Visiting interlisp.org with the Lynx web browser on Medley Interlisp. The main window is a VT100 terminal emulator running Lynx on the host operating system, Linux in this case. The smaller window next to the terminal is a VT100 keypad.

#interlisp #LynxBrowser #lisp
Screenshot of the black and white desktop of a 1980s graphical workstation environment. The desktop has a grey background pattern and some windows with a white background and a title bar with white text on a black background. The main window is a VT100 terminal emulator running the Lynx web browser on Linux open on the site https://interlisp.org At the left of the terminal is a window showing a virtual VT100 keypad.
February 14, 2026 at 10:12 AM
interlisp.org
The original documentation and literature of Interlisp-D used the verb "to button" like today we say "to click", i.e. meaning to press a mouse button.

#interlisp #retrocomputing
February 11, 2026 at 11:14 AM
interlisp.org
The manual of EMYCIN, a rare document published in 1981, is now available at Bitsavers. Developed in Interlisp at Stanford University, the EMYCIN expert system shell was derived from the early expert system MYCIN.

bitsavers.org/pdf/stanford...

#ai #ExpertSystem #interlisp #retrocomputing
bitsavers.org
February 8, 2026 at 10:05 AM
interlisp.org
We posted the manual of Medley Interlisp for MS-DOS originally published in 1993:

github.com/Interlisp/DO...

To run Medley for MS-DOS on DOSBox-X and QEMU see:

github.com/orgs/Interli...

github.com/Interlisp/me...

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#interlisp #msdos #retrocomputing
github.com
February 5, 2026 at 4:32 PM
interlisp.org
The SEdit structure editor of Medley Interlisp lets you also modify arbitrary list structures and data, not just Lisp code. In this example the ED function calls SEdit and returns the modified object.

#interlisp #lisp
Screenshot of a portion of the black and white desktop of a 1980s graphical workstation environment. The desktop has a grey background pattern and two windows with a white background and a title bar with white text on a black background. The bottom window is a Lisp REPL where the following expressions are evaluated, output printed, and values returned: 2/4_ (SETQ LIST.STRUCTURE (LIST 1 2 3 4 5)) (1 2 3 4 5) 2/5_ (ED 'LIST.STRUCTURE) Editing VARS definition of LIST.STRUCTURE. LIST.STRUCTURE 2/6_ LIST.STRUCTURE (1 2 3 (A B C) 4 5) The top window is an editor that shows a Lisp list structure modified by the above call to the ED function.
February 3, 2026 at 9:59 AM
interlisp.org
We posted the manuals of the TEdit WYSIWYG editor and the Sketch drawing program of Medley Interlisp. Although originally published in 1987, most of the material still aplies to modern Medley.

files.interlisp.org/medley/libra...

files.interlisp.org/medley/libra...

#interlisp #lisp #retrocomputing
Index page for {MEDLEY}/library/tedit/docs/
files.interlisp.org
January 31, 2026 at 12:32 PM
interlisp.org
Interlisp-D releases were named after words related to music starting with successive letters such as Carol, Fugue, Harmony, Intermezzo, Koto, and Lyric. Medley was the last before work on the system petered out in the 1990s.

#interlisp #lisp #retrocomputing
January 28, 2026 at 9:56 AM
interlisp.org
Our 2025 annual presents the work we did last year to revive Medley Interlisp and its ecosystem. We would appreciate it if you could share the report, which may be of interest to potential users and other software preservation projects.

#interlisp #lisp #retrocomputing
January 25, 2026 at 11:06 AM
interlisp.org
In 1985 Xerox announced support for Prolog on its workstations and awarded development to Quintus for Xerox Quintus Prolog for Interlisp-D.

www.bitsavers.org/pdf/xerox/in...

softwarepreservation.computerhistory.org/prolog/#Quin...

#ai #prolog #interlisp #retrocomputing
www.bitsavers.org
January 22, 2026 at 12:07 PM
interlisp.org
We published the latest Medley Interlisp Annual Report, a summary of the work of 2025. Last year marked the fifth anniversary of the project and the report was an opportunity to reflect on what we achieved.

interlisp.org/project/stat...

#interlisp #lisp #retrocomputing
2025 Medley Interlisp Annual Report
Overview 2025 marked the fifth year of the Medley Interlisp Project. We began the project in 2020 by merging code fragments from different sources and versions which last ran two decades earlier on lo...
interlisp.org
January 19, 2026 at 11:08 AM
interlisp.org
ILsee is a Common Lisp GUI tool for viewing Interlisp source files.

journal.paoloamoroso.com/an-interlisp...

#interlisp #CommonLisp #lisp #McCLIM
An Interlisp file viewer in Common Lisp
I wrote ILsee, an Interlisp source file viewer. It is the first of the ILtools collection of tools for viewing and accessing Interlisp da...
journal.paoloamoroso.com
January 17, 2026 at 10:28 AM
interlisp.org
The 1984 Artificial Intelligence episode of the Computer Chronicles show featured demonstrations of some Interlisp applications: the ONCOCIN expert system and the Knowledge Engineering Environment expert system shell.

www.youtube.com/watch?v=_S3m...

#ai #interlisp #ExpertSystem #retrocomputing
The Computer Chronicles - Artificial Intelligence (1984)
YouTube video by The Computer Chronicles
www.youtube.com
January 14, 2026 at 10:11 AM
interlisp.org
In Interlisp PUSH and POP manipulate stacks represented as lists and work like the corresponding Common Lisp macros, but PUSH swaps the order of the arguments.

interlisp.org/documentatio...

#interlisp #CommonLisp #lisp
Screenshot of a portion of the black and white desktop of a 1980s graphical workstation environment. The desktop has a grey background pattern and one window with a white background and a title bar with white text on a black background. The window is a Lisp REPL where the following expressions are evaluated, output printed, and values returned: 2/5_ (SETQ STACK '()) NIL 2/6_ (PUSH STACK 1) (1) 2/7_ (PUSH STACK 2) (2 1) 2/8_ (PUSH STACK 3) (3 2 1) 2/9_ (PUSH STACK 4) (4 3 2 1) 2/10_ (PUSH STACK 5) (5 4 3 2 1) 2/11_ (POP STACK) 5 2/12_ (POP STACK) 4 2/13_ STACK (3 2 1)
January 11, 2026 at 10:26 AM
interlisp.org
Published in 1978, this paper by Erik Sandewall is one of the best introductions to the Interlisp environment and development style. It doesn't cover the graphical Interlisp-D system but the material still applies to Medley Interlisp.

dl.acm.org/doi/abs/10.1...

#interlisp #lisp
Programming in an Interactive Environment: the ``Lisp'' Experience | ACM Computing Surveys
dl.acm.org
January 8, 2026 at 9:47 AM
interlisp.org
On November 16, 2023 Steve Kaisler gave the talk “Software Archaeology: The Medley Interlisp Modernisation Project” at a London event of the Computer Conservation Society.

www.youtube.com/watch?v=VcRs...

#interlisp #lisp #retrocomputing
Software Archaeology: The Medley Interlisp Modernisation Project
YouTube video by Computer Conservation Society
www.youtube.com
January 5, 2026 at 11:03 AM
interlisp.org
The Software Preservation Group at the Computer History Museum compiled a list and bibliography of Interlisp implementations. Did you know that Interlisp also ran on IBM 360/370 mainframes?

softwarepreservation.computerhistory.org/LISP/interli...

#interlisp #lisp #retrocomputing
Interlisp family
softwarepreservation.computerhistory.org
January 2, 2026 at 9:43 AM
interlisp.org
In 1965 Peter Deutsch wrote a structure editor for LISP 1.5 which Daniel Bobrow and Warren Teitelman extended and ported to BBN Lisp. It eventually became the Interlisp structure editor.

softwarepreservation.computerhistory.org/LISP/bbnlisp...

#interlisp #lisp #editor #retrocomputing
softwarepreservation.computerhistory.org
December 30, 2025 at 10:25 AM
interlisp.org
A demonstration of defining a Lisp function with the SEdit structure editor of an old version of Medley Interlisp.

www.youtube.com/watch?v=2qsm...

#interlisp #lisp #editor
Lisp Editing in the 80s - Interlisp SEdit
YouTube video by thoughtupquick
www.youtube.com
December 27, 2025 at 12:24 PM
interlisp.org
An example of one way of defining, expanding, and calling an Interlisp macro similar to WHEN of Common Lisp. Macro definitions are represented by lists stored on the property list of a symbol. Here ARGS is bound to the CDR of the calling form.

#interlisp #lisp
Screenshot of a portion of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and one window with a white background and a title bar with white text on a black background. The window is a Lisp REPL where the following expressions are evaluated, output printed, and values returned: 2/4_ (PUTPROP 'WHEN 'MACRO '(ARGS (LIST 'COND (CONS (CAR ARGS) (CDR ARGS))))) (ARGS (LIST (QUOTE COND) (CONS (CAR ARGS) (CDR ARGS)))) 2/5_ (GETPROP 'WHEN 'MACRO) (ARGS (LIST (QUOTE COND) (CONS (CAR ARGS) (CDR ARGS)))) 2/6_ (SETQ FOO 3) 3 2/7_ (EXPANDMACRO '(WHEN (GREATERP FOO 2) (PRINT "Greater.") T)) (COND ((GREATERP FOO 2) (PRINT "Greater.") T)) NIL 2/8_ (WHEN (GREATERP FOO 2) (PRINT "Greater.") T) "Greater." T
December 22, 2025 at 9:29 AM
interlisp.org
Spy is the statistical profiler of Medley Interlisp. The tool periodically interrupts the running program to sample the functions in the current call stack and displays the data.

files.interlisp.org/medley/libra...

#interlisp #profiling #lisp
files.interlisp.org
December 19, 2025 at 10:59 AM
interlisp.org
Evaluate (INSPECTCODE 'FN), where FN is an Interlisp function name, to disassemble the compiled function and see the opcodes of Maiko, the Medley Interlisp virtual machine. This example also shows the corresponding source of the function.
Screenshot of the black and white desktop of a 1980s graphical workstation environment. The desktop has a gray background pattern and several windows with a white background and a title bar with white text on a black background. One of the two main windows shows the disassembly of the compiled Interlisp function APPEND with the opcodes of the Medley Interlisp virtual machine. The other window is an editor that shows the Interlisp code of the APPEND function.
December 16, 2025 at 9:56 AM
interlisp.org
Episode 17 of the Netstack.FM podcast features an interview with Larry Masinter on Interlisp and the Medley project, the PARC environment, the early history of the web, standards and protocols, and more.

netstack.fm#episode-17

www.youtube.com/watch?v=JZ7E...

#retrocomputing #interlisp #web #ietf
Netstack.FM — A Podcast About Networking and Rust
Interviews, monologues, and deep dives into Rust and modern networking systems.
netstack.fm
December 13, 2025 at 9:38 AM
interlisp.org
The canonical capitalization of Interlisp is "Interlisp" or "INTERLISP". InterLisp is much less common in the documentation of and literature on the system.

#interlisp #lisp
December 10, 2025 at 10:37 AM
interlisp.org
Ryan Burnside is doing Advent of Code 2025 in Common Lisp on Medley Interlisp.

www.linkedin.com/feed/update/...

#AdventOfCode #interlisp #CommonLisp
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