Trying to implement a spec-compliant gopher server on the Lisp Machine

Day 0

I came across the Old Computer Challenge while browsing HackerNews (as I do far too frequently) and it really piqued my interest. I unfortunately tend to be a very plan-heavy, implementation-light kind of person. While it means my mind is constantly churning through new ideas, my keyboard stays cold, and my gits stay uncommitted. I decided that this would be my chance to finally get something out of my head and into the world by hijacking the power of social pressure.

Getting into Lisp

On the top of my stack of machinations was Lisp. I had the pleasure of reading Mark Tarver’s excellent essay The bipolar Lisp programmer. I really connected with it, and Lisp approached language design in a way that felt motivated. Homoiconicity was especially alluring (I studied theoretical linguistics at the UofA for my BA, so parsers, ASTs, and the like are my first love).

During my forays into the Lisp mythos I couldn’t help but come across the Lisp machines. From the MIT CADR to the Symbolics machines, the idea of a single-process, single address-space system running Lisp was exactly the kind of turtles-all-the-way-down idealism that I find irresistible. I already had a faint recollection of Symbolics’ work in the field from an excellent Asianometry video and now I had the context to understand its appeal.

Thankfully Brad Parker and some other amazingly talented folks have put a ton of effort into making Open Genera (the OS for Symbolics’ Lisp machines) runnable on modern x86_64 machines. Since Open Genera was already designed by Symbolics to run on a virtual machine (the VLM) hosted on a 64 bit DEC Alpha UNIX workstations, running it on my Linux laptop is shockingly close to the original architecture.

What to make?

Since the topic of this year’s OCC is to ‘build something’, and since I am light on cash and materials, I decided I would try to bring some new functionality to the Open Genera ecosystem. I wanted something well-defined, accessible to the public, and complex enough to give me a tast of Lisp machine software development. For me, that really only left implementing a Gopher server.

I assume by timing and happenstance, Open Genera doesn’t have built-in Gopher support. Given how groundbreaking CL-HTTP was, I can understand why there would be little appetite for running anything else.

Open Genera 2.0 (the version I’m running) stands in the Goldilocks zone for a novel implementation. Unlike earlier Lisp machines, I have a system TCP package, so no messing about with Chaosnet. Since Gopher is pretty much just raw TCP over port 70, with a tiny bit of logic added on, most of the work is already done. I’m probably speaking with the naivete of inexperience, but the folly of fools is what gets projects started.

Day 1

This was unfortunately quite boring. I was running errands most of this Sunday, and didn’t have any time to sit down with my computer. However, through the power of generative AI I was able to at least learn a bit more about how Symbolics managed its software, and how Lisp works. I have to drive 40 minutes to get anywhere, so LLMs and STT have really changed how I learn while busy. Remember, I’ve never written anything in Lisp before, so this is a war on two fronts. The devil is in the details, and I’m sure most of the heartache is yet to come.