A few years ago I received a package of tapes that came from a TC2000 system, which was a supercomputer from the late 1980s built by a company called BBN (Bolt, Beranek and Newman). The data on these tapes was recovered without any issues, and it turned out to be a minor treasure trove of software for the TC2000, as well as its cousin the GP1000.
One of the tapes was an actual “boot” tape — the system would boot from this tape, which then allows the user to install the operating system (4.3BSD Unix) onto a hard disk. (Unfortunately the system installation tape was not part of this collection; just the boot tape, and a few other supplemental software tapes, so it isn’t possible to reconstruct a “complete” TC2000 system from what we have here.)
Ever since then, I’ve had a bullet point deep in my backlog to build an emulator for this system, and actually boot this tape image, and see the 4.3BSD kernel messages from 1989 flying across the screen. Sort of… like this:
The above is literally the live TC2000 system, booting into the real tape image with vmunix on it, running in your browser, and letting you interact with it (here is the source code!). Admittedly there isn’t much to do in this boot environment. It expects you to execute nxinstall and proceed to install the operating system onto a hard disk, but like I said, the actual full operating system is on another, missing tape. So instead, I took the boot tape image and combined it with some of the aforementioned “supplemental” software tools, which includes a number of games that you can play in the above console. Go to /usr/games/ and experience for yourself the kind of fun that users of the TC2000 were having in 1989.
(I should note that the emulation is not perfect, because much of it needed to be reverse-engineered from the actual instructions of the kernel executable. So, if any program you run in the emulator crashes or gets stuck, you can click the “Restart” button to reboot.)
The thing is, this emulator was built almost entirely by an LLM (Claude Opus 5, over the course of a few days of prompting and iterating), and you know what? I think I’m okay with that. If you’ll permit some philosophizing and grappling with the use of an LLM for a hobby project like this:
My hobby is retrocomputing. But ultimately, the real satisfaction I derive from this hobby is making something work. For me, the end result of seeing something working is the satisfying payoff. The tools I use for making something work are a secondary detail. Using an LLM is a new tool for getting something to work. That the LLM was able to build a TC2000 emulator for me is therefore a genuine win.
Is the win cheapened by the fact that I didn’t write most of the code? I don’t believe so. The fact is, if LLMs didn’t exist, then this random idea would have languished in my backlog forever, and would have never gotten done. Would it have been possible for me to write all this code myself? Absolutely, over the course of several years of this project taking priority over other things in my life, which would simply not be worth it. Is the win cheapened by the fact that “anyone can do it” now? I don’t believe so. Yes, it is true that anyone else could have done this. So then… go ahead and do it! Who’s stopping you from picking a random idea you had ages ago, and getting it done?
So there we have it: here is the repo of the TC2000 emulator, which emulates a Motorola 88100 CPU, an 88200 CMMU, and all the other accoutrements to get the system booted See the README file in the repo for much more details of how the system works. Unfortunately the emulator can’t go much further without more of the missing pieces from the original TC2000 system: ROM images, the full OS installation tape, and so on. Without these things, the emulator won’t be able to emulate the major selling point of this whole system: the “Butterfly switch” that actually allows multiple processor nodes to run processes independently (currently it emulates just a single node). If you or someone you know has access to these materials, or has additional stories from the BBN days, please get in touch!