John Carmack's arguments against building a custom XR OS at Meta

I was at Google when the Flutter team started building Fuchsia.

They had amazing talent. Seriously, some of the most brilliant engineers I've worked with.

They had a huge team. Hundreds of people.

It was so ambitious.

But it seemed like such a terrible idea from the start. Nobody was ever able to articulate who would ever use it.

Technically, it was brilliant. But there was no business plan.

If they wanted to build a new kernel that could replace Linux on Android and/or Chrome OS, that would have been worth exploring - it would have had at least a chance at success.

But no, they wanted to build a new OS from scratch, including not just the kernel but the UI libraries and window manager too, all from scratch.

That's why the only platform they were able to target was Google's Home Hub - one of the few Google products that had a UI but wasn't a complete platform (no third-party apps, for example). And even there, I don't think they had a compelling story for why their OS was worth the added complexity.

It boggles my mind that Fuchsia is still going on. They should have killed it years ago. It's so depressing that they did across-the-board layoffs, including taking away resources from critically underfunded teams, while leaving projects like Fuchsia around wasting time and effort on a worthless endeavor. Instead they just kept reducing Fuchsia while still keeping it going. For what?

Wasn’t Fuchsia supposed to be a platform where different OS could run in a virtual environment and software packages would be complete containers? Was not this a new way of tackling the ancient OS problem?

These were my imaginations. I thought maybe an OS that could run on the web. Or an OS that could be virtualized to run on several machines. Or an OS that could be run along several other instances on the same machine each catering to a different user.

I guess it's just a political shit show at this point. Ideas go hard if the people behind them aren't playing the game well enough, no matter their value.

And the crazy thing is there is arguably a lot more of a reason for Meta / Oculus to have had its own operating system because it is meant for a specific configuration of hardware and to utilize those hardware resources to a quite different goal than most other OSes out there. Even in that environment it was still a waste

Reinventing QNX will be cutting edge for decades to come.

Not only did they target Home Hub, they basically forced a rewrite on it (us, I worked on the team). After we already launched. And made our existing workable software stack into legacy. And then they were late. Then late again. And late again. With no consequences.

100% agree with your points. To me watching I was like -- yeah, hell, yeah, working on an OS from scratch sounds awesome, those guys have an awesome job. Too bad they're making everyone else's job suck.

There's few things worse for the long-term health of a software project than people who have hammers and are hunting for nails for them.

I always felt that Fuchsia was a make-work program to keep talented kernel engineers away from other companies. Sort of a war by attrition.

It's a lot of work and hard to justify if you're looking for short term improvements. But if you're really committed to long term improvements, it absolutely makes sense. Google is actually willing to make long term investments. Publicly justifying the investment has never been a goal of the project which is why most folks probably don't understand it. Honestly I'm not sure why folks care enough to even do commentary on it. If you find it useful, you can participate, if not just ignore it.

Fwiw inventing a new application ecosystem has never been a goal and is therefore not a limitation for its viability. The hard part is just catching up to all the various technologies everyone takes for granted on typical systems. But it's not insurmountable.

I'm also not sold on the idea that having more options is ever a bad thing. People always talk about web browser monoculture and cheer on new entrants, yet no one seems to mind the os monoculture. We will all come out ahead if there are more viable OS out there to use.

That doesn't sound anything like what fuchsia is or ever was. Fuchsia takes a different set of tradeoffs with respect to baseline primitives and built a new stack of low level user space on top of those new primitives. This gives the software fundamentally different properties which might be better or worse for your use case. For consumer hardware products I think it comes out ahead, but only time will tell.

That's a weird rumor that I'm not sure I understand. Things are not that complicated.

Isn't this how folks use Linux today? It's the only tool they know and don't understand the tradeoffs, hurting the product.

> People always talk about web browser monoculture and cheer on new entrants, yet no one seems to mind the os monoculture. We will all come out ahead if there are more viable OS out there to use.

3 main OSes vs 2 main browser engine for consumer to choose from?

Anyway the main issue with the Browser engine consolidation is that whoever owns the Browser engine, can make or break what goes in there. Just think about VSCode's current status with all the AI companies wanting to use it and make it their own product, while MSFT attempting to curtail it. At some point either MSFT decide it commit to FOSS on this one, or the multiple forks will have to reimplement some functionalities.

I think the hope is that you just start there. They might have migrated the meeting room devices. Why would you set out to replace *everything* at once? Do something, get some revenue/experience, then try to fan out.

Other teams decommitting is just how it goes.

I think what op was thinking of was early harmonyos, seen people confusing those a lot. Harmony now ofc isn’t what

By forced I guess you’re referring to the room full of leads who all said yes, but then reported otherwise back down to their ics to avoid retribution. I caught early wind of this from folks being super rude in early on the ground discussions and tried to raise it with Linus. One of the directors got his kickers in a twist and accused me of making a mountain out of a molehill. I guess clearly not, as the sentiment and division still stands.

I always wonder why companies prefer rolling the dice to pragmatism.

Microsoft used to legit do this in the 90s. Recruit bus factor 1 employees from competitors by offering them large salaries.

It was much easier to cripple your competition back when there were several orders of magnitude less software engineers in the world.

Yeah, those were definitely your imaginations.

My understanding is that people are working on Fuschia in name only at this point. Of course some people are passionate enough to try and keep it alive, but it’s only useful to the degree that it can help the Android team move faster.

If it's even a rumor then I started it, I just can't imagine Fuchsia serves any other purpose. I don't even usually give Google a lot of credit, but I just can't imagine they made something this useless and misunderstood the feasibility of such an OS this badly. It would be like Hewlett-Packard in the early 2000s levels of incompetence.

I don't care who agreed to what, it's bad engineering practice to take a working successfully launched product and throw out its entire working software stack no matter how inelegant it seems. To what end? What did Fuchsia offer? When it finally shipped -- what, 2, 3 years late? --- custmers couldn't even tell it happened.

And in order to make it happen it also required writing the already-launched HTML-based UI in Flutter/Dart. Again ... why? What for? There wasn't even a working "native" Flutter at the time, despite promises, and there certainly wasn't a working accessibility stack -- no screen reader, no magnification, nothing -- so that all had to be kludged in. It was everything wrong with the "rewrites considered harmful" distilled.

Not to mention terrible for morale, execution, planning, budget, customer satisfaction.

I was just a lowly SWE 3 "IC" just in the trenches, not nearly as "important" as all that, so my opinion mattered not at all. But to me it violated every sound engineering / project planning principle I'd learned in the 15 years of my career up to that point. Just another event that led to me becoming quite cynical about the ability of leadership at Google to actually manage anything of significant complexity that wasn't ads/search related.

Again, Fuchsia .. very neat. But it didn't belong there.

Customers not being able to tell that it happened was a goal of that deployment.

It wasn’t anywhere near that late the numbers you’re saying was about the whole build cycle - board bringup for one of the two boards first commit in zircon was 3y before launch (that codes public, I just checked and Mike landed it in 2018) - and discussions weren’t done then, that was before any prototype/demos could be done. There were sluggish stages and project management was rough, and there were delays at the end related to quality but the quality bar was necessarily high, particularly on the core system - don’t brick all the devices in the field. And we didn’t, and that’s actually a feat replacing everything from firmware to gui in the field without users noticing.

What was the goal? Well two things: fuchsia needed a first, and realistic shipping target that wasn’t excessively lofty. Nest needed to get out of the OS game so it could focus resources on product. Chris talked about this in his 9to5google interview.

It’s a shame you feel so sour about it, everyone involved did good work. I have friends from nest and some of the ics also have similar pained history from that time - it’s sad, once upon a time it was maddening. It’d have been so easy for a leader to substantially improve that. Sure plenty of things could have been better, for sure we could have fixed these awful sentiment and relationship issues (I tried, got burned for it - that even showed up in my calibration), but we all shipped.

A bad business decision, yes. But is it any good?