Lex Bailey's Fax Server Compiles Your Source Code — And Calls You Back with the Output

Maker Lex Bailey has reinvented the teletype, creating a compiler that may be a little more inconvenient than most — by requiring you to fax your source code and wait for a callback.

"I had a spare weekend, and a terrible idea, so I made it happen," Bailey says of the project, which was created ahead of the Electromagnetic Field festival later this month and its field-spanning local telephone network. "There's some C code that needs compiling here. If only there was some sort of service I could call, that I could fax this C code to [and] would compile it for me, and run it, and tell me what it did."

A programmer working with a compiled language like C traditionally uses a compiler on their local machine, feeding it the program's source code and receiving a binary in response. That wasn't always the case, though: in the early days of computing, mainframes were shared by multiple users who communicated them through teletype terminals — devices which accepted a program, either typed on a typewriter-like keyboard or loaded from punch tape or cards, and sent them over a telephone line or other communication system to the mainframe to run them before printing out the response.

Bailey's creation is, effectively, a teletype, but reimagined. A modern multi-function print-fax-scanner machine is used to dial up the server over a plain old telephone system (POTS) and transmit the scanned page of source code as a fax. The fax is then run through an optical character recognition (OCR) system to turn it back into text, fed to a compiler, and the result returned to the user — as, naturally, another fax.

Following a proof-of-concept installation at York Hackspace, which has an internal telephone system suitable for testing, Bailey plans to install the fax-compiler at the Electromagnetic Field festival from 30 May to 2 June — where it will be available for attendees to fax their own source code for compilation, using a private phone system spanning the field in which the festival takes place.

Those interested in learning more can reach Bailey on the project's Mastodon post, or in the comments on the YouTube video demonstrating the system.