Compile and run Joseph Weizenbaum's original 1965 code for ELIZA on CTSS, using the s709 IBM 7094 emulator.

• elizagen.org blog post
• Video demo
• Paper

Updating from an older version? See UPDATING.md. Note there is a new step in the Quickstart where you need to login as sysdev.

You will need a Unix like environment that can compile C code and run Python and shell scripts. This has been tested on

• Arch Linux
• Debian
• MacOS

but may work on other Unix/Linux flavours.

You will also need the telnet command line program or a GUI telnet client. The command line program can be installed by sudo apt install telnet on Debian/Ubuntu or brew install telnet on MacOS.

If you just want to try ELIZA, follow the below steps to bring up CTSS and get ELIZA compiled and running. If you'd like to find out more about each step, see HACKING.md.

1. Fetch this repo and set up the environment.

$ git clone https://github.com/rupertl/eliza-ctss.git
$ cd eliza-ctss
$ source env.sh
$ make-binaries
$ make-disks

2. The next two commands will prompt you to press Enter a number of times and then q to quit.

$ format-disks
$ install-disk-loader

3. Continue installing CTSS and the ELIZA source.

$ installctss
$ add-eliza-users
$ upload-all

4. Start CTSS by typing runctss
5. Start your telnet client and connect to localhost port 7094. For the command line client you can type telnet 0 7094.
6. In the telnet session, type login sysdev and give the password system
7. The screen should now look something like

$ telnet 0 7094
Trying 0.0.0.0...
Connected to 0.
Escape character is '^]'.
s709 2.4.3 COMM tty0 (KSR-37) from 127.0.0.1

MIT8C0: 1 USER AT 02/01/25  921.5, MAX = 30
READY.

login sysdev
W 921.6
Password
 M1416     6 LOGGED IN  02/01/25  921.6 FROM 700000
 HOME FILE DIRECTORY IS M1416 SYSDEV

THIS IS A RECONSTRUCTED CTSS SYSTEM.
VERSION: 1.0.8
BUILT: 01/25/25 1053.0

 CTSS BEING USED IS: MIT8C0
R .033+.000

8. Type runcom mkhuge and wait for it to print MKHUGE HAS BEEN RUN.
9. Type login slip and give the password slip
10. Type runcom make and wait for it to print MAKE HAS BEEN RUN.
11. Type login eliza and give the password eliza
12. Type runcom make again and wait for MAKE HAS BEEN RUN.
13. Type r eliza
14. Give the answer 100 to the prompt of which script to use
15. ELIZA will print a greeting and you can now interact with her. Keep your responses below 72 characters and press Enter twice to submit. This is how your screen could look after a first response.

r eliza
W 1916.6
EXECUTION.
WHICH SCRIPT DO YOU WISH TO PLAY
100
HOW DO YOU DO . I AM THE DOCTOR . PLEASE SIT DOWN AT THE TYPEWRITER AND TELL ME
YOUR PROBLEM .
INPUT
Men are all alike.

DID YOU THINK THEY MIGHT NOT BE ALL ALIKE
INPUT

16. When you are finished, press Control-\ (backslash) to interrupt and then type logout.
17. Shut down CTSS cleanly. You will need to switch back to the main emulator window you started earlier - this cannot be done from the telnet session.

Execute the following, pressing Enter after each non Control-C line.

• Press Control-C
• Type ek 40017
• Type st
• Press Control-C
• Type ek 0
• Type st
• Press Control-C
• Type ek 40032
• Type st
• Type q and Enter to exit.

18. If you want to run ELIZA again, do runctss and then telnet in as user eliza and r eliza like before. (You do not need to recompile it).

If you would like to try different personality scripts for ELIZA, read SCRIPTS.md.

To learn more about compiling ELIZA, and how to make your own changes to the soruce code, see HACKING.md.

If you would like to read more about the process of reconstructing the code from the printouts, see RECONSTRUCTION-CARD.md.

To find out more about CTSS, see my blog post series at timereshared.com.

The goal of this repository is to get ELIZA running in its original form with as few modifications as possible. There are missing features and bugs from the original code: see KNOWN-ISSUES.md for details.

The ELIZA and SLIP library code under eliza/ is from the source code printout which was found among Weizenbaum's papers at MIT by Jeff Shrager and the MIT archivists, and transcribed by Anthony Hay and Arthur Schwarz respectively. Weizenbaum's estate has kindly agreed for this to be open sourced under a Creative Commons CC0 public domain license. About 4% of the SLIP library were missing in the original printout; these were re-implemented by Anthony, Arthur and Rupert Lane and are found in eliza/src/SLIP/SLIP-reconstructed with tests in SLIP-tests. This newer work is also licenses as CC0.

The s709 emulator, ctss-kit and utilities under ctss/ are from Dave Pitts' IBM 7090/7094 page, based on previous work on s709 by Paul Pierce, with minor modifications by Rupert. This uses the MIT license, see LICENSE.txt.

CTSS environment set up, upload and runcom scripts are by Rupert, licensed as CC0.

The ELIZA script eliza/src/ELIZA/tape.200 is adapted from Weizenbaum's article for the Communications of the ACM in 1966.

Thanks to everyone on Team ELIZA for their help and advice,

Please raise an issue/pull request if you see any problems, or email me at rupert@timereshared.com