GitHub project rebuilds 1960s MIT operating system

A GitHub project has set itself the goal of rebuilding the so-called Incompatible Timesharing System. This is done in an operating system developed in the 1960s, which ran on PDP-10 computers, among other things.

The project was discovered by The Register and states in its objective that it aims to rebuild the ITS ‘from scratch’. That operating system was developed about fifty years ago by employees of the artificial intelligence laboratory of the American MIT. This system allowed different users to jointly use the capacity of, for example, a DEC PDP-10 system by means of timesharing. The name of the system is a playful reference to the MIT-OS with the name Compatible Time-Sharing System. Users could use the system remotely via Arpanet.

The system was in use until 1990 and was written in assembly language. In contrast, the applications for the system were often written in LISP, a programming language that became the standard for artificial intelligence development. The popular text editor Emacs, among others, was written on the ITS. Working on the system must have been quite frustrating for some time as users kept looking for ways to make it crash. This was fixed by entering a command that would allow anyone to crash the system and immediately show who was responsible for that action.

The GitHub project, which is under the name of Lars Brinkhoff, aims to develop an automated build of the ITS. It also wants to find out which programs have source code and which ones are missing. It also wants to update and improve programs. To run the ITS, a KLH10 emulator is needed. Even telnet, ftp and tcp are supported.

A DECsystem-1090 with memory modules, photo by Retro-Computing Society of Rhode Island – own work, CC BY-SA 3.0