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uxn: a portable 8-bit virtual computer (100r.co)
230 points by bpierre 37 days ago | hide | past | favorite | 47 comments

This whole thing feels like the INFOCOM way of doing things.

Everyone probably knows, but INFOCOM did the Zork type text adventure games. They chose to author to a virtual machine, which could be ported to many machines once, making all their games playable across a ton of machines.

Today, their software is very accessible. Porting a Z machine is not a super heavy lift. Once done, the library of interactive fiction games is available.

This machine might make a great target for micro controllers and or other smaller scale systems. Could be fun, and a source of smaller scale software for people to explore, build on.

Damn cool! First I've read about this.

By the way, portability was only a side effect of the Z-machine. The main purpose was code size. A text adventure compiled down to the Z-machine would take up less space than the same program compiled to machine code. They were written in the Zork Implementation Language (ZIL), which is similar to Lisp.

Yes, as I understand it, that is true.

>This machine might make a great target for micro controllers and or other smaller scale systems.

- V3, perfectly. Infocom games and Puny Inform ones. The best would be the 12th release of Curses in v3 format.

- A V5 game would run pretty slow on a C64 for example, you'll need a Turbo Chameleon to run the games at acceptable speed. As acceptable I mean max 4-5 sec lag.

- V8 games like Anchorhead are a "no-no" under an 8bit machine. Using telnet/serial against a 16 and more bit machine would be the sanest option.

Depends on the 8-Bit machine doesn't it?

I have an Apple //e Platinum running at 16 megahertz. Might do V8 fine.


I tried with Vice, REU, Turbo @18mhz and Ozmoo.

Running Anchorhead was impossible, and even V5 games such as Vicious Cycles ran borderlinely unusable. I mean, playable over a lag of 8-10 seconds after inputting the command, but it gets tedious fast.

Bummer. Well, a whole lot remains interesting, thanks for the data points!

This is oddly cool a hip, alternative and artistic kind of way. The philosophical motivations for their projects sound dreamlike to me, almost like ideological activism, enough that it'd make you feel that the work that you're doing gives your life some sort of unique meaning. I envy this lifestyle of adventure and creative expression, an idea for a more fulfilling human experience that I somehow know I can never have, but I don't really understand why.

Agreed, I view projects like this as important experiments and inspiration for the wider community. It's good to have people around that are willing to try out implementing lofty and idealogical ideas - even if it ultimately fails at it's intended goals directly, they occasionally spawn the most uniquely valuable unintentional gifts to civilisation.

I feel a similar way. As far as adventures go, I can sometimes find time to do a project on old or simple gear.

Counterpoint: Dreamlike hipsterism is utility 0 navel gazing; there's nothing inherently transcendent about computing. You'd do more for the world at a local food bank; it's slacktivism and virtue signaling of the worst kind to see electronic baubles as transcendent or somehow worthy of permanence, the kind of naivete the bubble of Web 1.0 popping should have destroyed, or the misinformation campaigns of the last election, or the latest data breach should have destroyed.

If you want artistic sensibility, fine. But pretending a personal crusade to make permanent computers you can build as an undergrad sophomore is somehow a noble cause is pretending your hobby is cosmic in importance and utterly delusional.

It's like people who bloviate about GPL licenses: you can tell they've never gone to bed hungry.

I can't find in the text where they're pretending a personal crusade of any kind, let alone any virtue signaling aside from not wasting too much solar battery on tech. Why are you giving so much importance to something you despise so much? They live rent free in your head?

Sometimes naivete is what allows a person to create something that no one else thought was possible.

I agree, and through that dynamic, we have a rich field of exploration / experimentation to draw from.

Just look at all the lessons to be learned from systems of the past. And what can actually be done on them!

I agree with everything you said, and at the same time, holding those beliefs early in my career held me back immensely. I regret not befriending those strange folks and getting some of that delusional energy, it's useful sometimes, and now, I think, more often than I would have predicted when I was younger.

TLDR; avoid personal dogma in tech, or don't, I'm not your dad, and who's he to tell you what to do anyways?

> We want to produce lasting versions of our tools and games, and by using simpler systems(Uxn has only 32 instructions) we can build more resilient software due to their lack of dependencies, and support older hardware when possible.

Lately I've been thinking a lot along similar lines, but have come to a wildly different conclusion about how to do it. Of course, they are explicitly limiting their use-cases so that's to be expected. I generally agree with the idea of a VM that is simple to implement, but I think the result shouldn't look like real hardware with memory addresses and registers and a stack and all that, it should be more abstract and leave more implementation details up to the interpreter/jit.

Regardless, it makes me slightly less gloomy about the future of computing whenever I see more people coming to similar conclusions.

> I generally agree with the idea of a VM that is simple to implement, but... shouldn't look like real hardware

You might appreciate appreciate Urbit's Nock, a "functional assembly language" based on combinator calculus which can be specified in ~40 lines of text, and implemented in ~100 lines of code:


As one might imagine, a naïve implementation of this spec would be extremely slow (for example, decrementing n requires incrementing another variable m in a loop until m+1==n, which is O(n)). A regular JIT can make even the braindead implementation decently fast, but in practice, specific implementations are recognized by the interpreter and replaced with faster ones. The benefit of this approach is that the code itself is rigorously specified by the combinator definition, and you can point the finger at the interpreter if the output from the optimized version differs from the naïve implementation.

> As one might imagine, a naïve implementation of this spec would be extremely slow (for example, decrementing n requires incrementing another variable m in a loop until m+1==n, which is O(n)).

Yeah, see that seems to go way too far, but then again this stood out as similar to ideas I've had:

> The algorithm for decrementing an atom is to count up to it, an O(n) operation. But if the interpreter knows it's running a decrement formula, it can use the CPU to decrement directly.

I had basically the same idea, only since my ideas still look a lot more like an instruction set it was in the form of explicit annotations to identify functions that could be replaced with a specialized instruction if available.

I'll have to look into this thing. Thanks.

Nock does in fact use explicit annotations (called "hints"). I believe it also verifies that the annotated code "looks right" for the hint, but I don't think it scans all code fragments to see if they implement decrement (for example).

When you said a VM that doesn't look like real hardware, I thought maybe something like WebAssembly! Maybe even that's too HW-y though? (stack, no registers, structured control flow, interaction with outside world only through function calls)

My current "VM" inspirations include...regular expressions, constraint logic, modular synthesizers, three-ring binders.

You can go really, really far away from a computing system being a Turing machine with arithmetic, if you work at it - like, that's the thing you already have in every PL. But I think getting away from that also entails getting down and dirty with your chosen benchmark of expressiveness, and accepting that the system does not do some things well, and if you want to have multiple things coordinated, then you need to be careful about expressing that, too, to avoid just making a Turing tarpit.

Yeah this is exactly why I came up with whistlegraphs. I was doing a lot of thinking about how to define a VM for dynamic graphics and drawing and then realized I could start to specify things at a much higher level of abstraction before ever needing the computer. (https://www.youtube.com/watch?v=YXUUCkqv2LY)

Well that was a delightful video. Very whimsical.

why thank you

Actually what I've been toying around with mentally has some similarities to web assembly, like only interacting with the outside world through function calls, but I personally feel webassembly suffers from a lot of design by committee.

The Hundred Rabbit folks are talented and inspiring. I've loved following along their journey, and some of the software they've produced is seriously impressive (check out Orca!).

They've got a Patreon, which I've happily supported for a while https://www.patreon.com/100.

> As it stands today, most software is built with extreme short-sightedness, designed to be run on disposable electronics and near impossible to maintain, we decided to not participate in this race to the bottom.

This is a cool project, but it doesn't seem to me like it demonstrates great foresight or maintainability. The compromises that areade in commercial hardware and software aren't only made just to be evil, but also to make things affordable and useful and widely available.

I would take a look at the rest of 100rabbits' site. Their whole ethos is artistic, interesting, and anti-commercial. Really fascinating stuff and might put this project into more context.

It's certainly interesting and fulfills a purpose. I just don't think the stated reasons are as solid.

> Uxn has only 32 instructions

A 6502 has about 30 mnemonics (if you consider the A/X/Y forms together as register addressing modes rather than instructions).

I agree, the motivations are razor thin.

And don't get me wrong, it's awesome. It's a tiny stack machine complete with its own language! And graphic capabilities!

If the page just said "I made it just for the heck of it" I wouldn't like it any less.

The best things are made by people who make them for specific reasons, even if you don't agree with or understand those reasons. Good art is made by including aspects that you want and rejecting those you do not want. In the case of Hundred Rabbits, their entire body of work would not exist without these motivations.

And really, I doubt that many people make things "just for the heck of it". In reality, they probably have motivations but don't, won't, or can't articulate them.

They built uxn to replace Electron

This is very cool. I've always wanted a "virtual platform" that can run on even the creakiest of hardware. I especially like that it uses ASM instead of some embedded language.

Some people think of the Pico-8 as this but it's actually got pretty high minimum specs! Higher than the GBA! (Which is my typical "runs anywhere" platform of choice)

Maybe the graphics are a bit too limited though? 2bpp for the entire screen is a tough sell (Wassup my Apple ][ and Amstrad CPC fans)

The sound limitations are pretty cool and remind me of the Amiga.

As for the ASM specs, I'll have to wait and see what more experienced programmers have to say on that one. I remember people picking over the DCPU 16's ASM and there having to be revisions.

If you are interested in something really simplistic to get into and slightly related, check out SUBLEQ and High Level Subleq. The C code can be like a one-liner if you want. (Although if you handle a few basic things with output buffering and spread it out a little its more like 13 lines https://github.com/runvnc/sq/blob/master/sq.c). This one might work better, don't remember https://github.com/runvnc/sq/blob/master/sq2.c


All it does is output characters to STDOUT, but you can do really interesting things with that micro VM and and an ANSI graphics terminal. Also started messing with Tektronix vector graphics which xterm supports.

Great to see hundred rabbits on the front page of hn! I read everything they post -- most recently they inspired me to go down a long plan 9 rabbit hole.

I so completely admire their skill, dedication to sustainable living, aesthetic. They're on a completely different level of hip.

I’m always amazed at the quality and quantity of the projects that 100r are capable of building!

Kudos to them!

Those two are a huge inspiration for sure! I can recommend their youtube channel: https://m.youtube.com/channel/UCzdg4pZb-viC3EdA1zxRl4A

nice, i like the aesthetic and the minimalist mindset. i get that small is beautiful and constraints are useful to get to the essence, but I was thinking that fuzix would be more versatile on 8/16 bit chips while easy to virtualize - or would it be less power efficient or needlessly complex? http://www.fuzix.org/

Someone got it running on the RPi Pico http://cowlark.com/2021-02-16-fuzix-pi-pico/

There also is mruby, version 3 can load applications in just 100 Kb.

How would these projects compare or differ with the minimalism and design goals of uxn?

less is more from MIT https://spectrum.mit.edu/winter-2007/less-is-more/

Uxn running on the Pi Pico: https://twitter.com/hundredrabbits/status/139219273489976115...

Here's how fast it renders animations on a Memory Display: https://merveilles.town/@alderwick/106222101764116637

The DVD bounce program is 317 bytes long when assembled: https://git.sr.ht/~rabbits/uxn/tree/master/item/projects/exa...

Slightly different targets, from what I can tell. Uxn starts with a virtual machine spec and builds up from there. The proposed language is simple, and a self-hosted translator wouldn't be too much work. Kind of reminds me of Forth. (Edit: Oh! There already is a self-hosting assembler: https://git.sr.ht/~rabbits/uxn/tree/master/item/projects/sof... )

FUZIX assumes you have a machine of some kind already, and a C compiler for it. I suppose if someone wrote a C compiler targeting Uxn, one could port FUZIX to it in principle.

This is beautiful in a way. It reminds me of a future long past.

In a similar vein, wasm has been used for archival purposes. It's likely that a wasm binary compiled today will be able to run many decades in the future, perhaps on architectures not even dreamt of yet.

>"Uxn is a portable 8-bit virtual computer capable of running simple tools and games programmable in its own little assembly language."


"Why Create A Small Virtual Computer?

We want to produce lasting versions of our tools and games, and by using simpler systems(the UxnVM is only 200 lines of C) we can build more resilient software due to their lack of dependencies, and support older hardware when possible.

The Uxn emulator is extremely simple, and can be ported to an unsupported system fairly easily."

The pico-8 of computers

The mascot looks like something Renée French would draw. :)

I was not aware of that, but a quick look shows that the officiel mascot of Plan 9 actually was drawn by Renée French (see http://glenda.cat-v.org/ ). I don't know whether the specific mascot for the uxn project also comes from her or not, but we know that Devine and Rek use the Plan 9 OS (see https://100r.co/site/about_us.html ).

love the design

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