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John Carmack
@ID_AA_Carmack
AGI at Keen Technologies, former CTO Oculus VR, Founder Id Software and Armadillo Aerospace
Dallas, TXJoined August 2010

John Carmack’s Tweets

Someone noticed that when you have hundreds / thousands of cores in a supercomputer, the individual utilization boxes in Task Manager start to look like pixels. People started making pictures by doing different amounts of work on specific processors. It escalated quickly. t.co/hqogF8UVYM
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A troll was trying to get a rise out of me yesterday, suggesting that I should somehow feel bad about Elon's success after my failed aerospace venture. I can't overstate how alien that thought is to me -- my joy at these things being built is deep.
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Moving rocket to orbital launch pad
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I still get nervous even for other people’s rocket launches. The knowledge that all your work could go up in a giant explosion is a special kind of frisson. But for everyone that has ever drawn a spark of inspiration from visions of humanity expanding into space:This is the Way.
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Targeting as soon as Monday, April 17 for the first flight test of a fully integrated Starship and Super Heavy rocket from Starbase in Texas → spacex.com/launches
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Starbase is extremely impressive. There is a lot of bemoaning that we culturally can't build physical things anymore, but this is China Speed and then some. Rows of engines, hangars full of structures, 24/7 shifts -- it is a sight to behold.
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Replying to @ID_AA_Carmack
It would be an honor to have you visit Starbase
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Great! I think Microsoft has been a good parent company for gaming IPs, and they don’t have a grudge against me, so maybe I will be able to re engage with some of my old titles.
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Xbox buys Bethesda parent Zenimax, including internal studios such as id Software and Arkane - but Bethesda will still publish its own titles gamesindustry.biz/articles/2020-
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Replying to
I may be reading this incorrectly, but if you are actually deleting inactive accounts and all their historic tweets, I would STRONGLY urge you to reconsider. Letting people know how many “active” followers they have is good information, but deleting the output of inactive… Show more
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Last night I downloaded Quake III Arena on Steam. I always looked back at it as my favorite Id game, but it had been many years since I had actually played it. There are a few polish things that I would nitpick today, but it was like dropping a quarter in a classic arcade game.… Show more
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It is interesting how multiple polls show that most respondents think Twitter will likely be somewhat better in the future, but the conversation on Twitter itself is dominated by confident predictions of catastrophe. I wish there were good prediction markets to advocate for.
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So, 50 years old now. I am down a point of Str and Dex from my younger days, but I'm a more capable engineer than ever. I'm noticing more people in their 70s that seem sharp and spry, so I'm looking forward to at least a couple more decades of relevance.
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It is hard for people today to comprehend how slow an original IBM PC was. By some measures, a 4090 is a billion times faster, which means a PC working continuously for 40 years could be replaced by one second of modern computing. And yet, this could be done.
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This is pure wizardry youtu.be/-xJZ9I4iqg8 I believe @ID_AA_Carmack will find this amusing.
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I had been considering writing something along these lines myself. I'm surprised how many people are so eager to see brought low. I admire him.
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In Defense of @ElonMusk: The Tesla and SpaceX maestro is under attack for bad tweets, production woes, and strange behavior. But we need people who take risks. We need people who try. The new cover story: popularmechanics.com/space/rockets/
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When I first started getting successful in my 20s, I went through a period where I loaned money to anyone that asked me. Well into six figures went out — “emergency” expenses, start a business, make a down payment, etc. Most of the people just never spoke of it again, and \
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I find it surprising that Windows considers it an acceptable default to just reboot users’ machines after applying an update in the middle of the night.
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Last week, when my Uber driver asked where I had been and I said “watching a rocket launch”, she lit up with excitement, because she had watched it online. She was from Kenya, and filled with enthusiasm for space exploration, solar power, batteries, and electric cars. She was… Show more
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It is 's 20th anniversary today. It is hard to remember from today's perspective how viciously the idea of a publicly edited encyclopedia was mocked by many traditional gatekeepers of knowledge. It is hard to imagine a better refutation.
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The spinal cord has about the same number of neural connections as the optic nerve — to your brain, all of your body from the neck down is worth about one eye.
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Just ordered a couple 1TB thumb drives for $30 each. I still find myself awestruck by tech progress -- I desperately wanted a 10MB hard drive for my IIGS as a teen, but didn't have the $399. One million times cheaper per byte, one thousand times faster, and 100 times smaller now.
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I do not have “magical” discipline and focusing ability — I struggle with distractions like everyone else. Often it is better to just remove the option to distract yourself instead of fighting he urges. When I decided to get serious about my AI work, I made a few changes: \
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If a future Neuralink implant is to allow bidirectional communication between a human and an AI, it is unclear which entity would be the peripheral. Even today's narrow AI can be super-human at controlling balky, recalcitrant actuators, given feedback and enough trials.
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Hey -- How about Teslas as VR input devices. Add a 'controller mode' that allows a headset to pair with the car to get steering / pedal / switch input. Better than a dedicated racing cockpit for drivers' ed and gaming. I let my son drive my S around a bit today...
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With all the GPT4-will-change-everything hype and fanfare happening now, it is worth mentioning that I just had to deal with some rural contractors that DIDN’T HAVE EMAIL ADDRESSES. The system of the world has more inertia than it sometimes seems.
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I spent *hours* today debugging something that turned out to be a single wrong letter in the code: a .ge() should have been .gt(). Beginning programmers sometimes despair when debugging, but with experience it is just something to grind through.
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I don’t feel it, and I don’t think it is rational, but I do see it. The zeitgeist of the thought leaders does tend negative. I remember waving my flag of technological optimism in the 90s and getting smiling chuckles from people, while now I can count on at least some angry… Show more
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do you feel it too? the absence of any optimism for the future? it’s completely gone from the cultural zeitgeist. such a stark contrast compared to the early 00s. or is it just me getting old and jaded and looking at the past through a nostalgia filter?
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I know there are decent odds something will go wrong with the launch today, but I'm not really nervous, because I know that even in the worst case, they will clean up the rubble, learn lessons, and get on with it. On the other hand, the best case is GLORIOUS!
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A common mistake I see in UI work is fades/transitions taking too long. UI should work in "game time", not "cinematic time". A transition should happen as fast as an impatient user can button mash -- a small-integer number of frames.
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I used to say that AI research seemed to have an odd blind spot towards automation of programming work, and I suspected a subconscious self-preservation bias. The recent, almost accidental, discovery that GPT-3 can sort of write code does generate a slight shiver.
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By my mid 20s I had made some conclusions about myself like “I’m not a higher math guy” and “I’m not a Unix guy”, and I have let them color my work for decades. I work with math and Unix, but I never feel fully aligned with those who are deeply enmeshed. I have had plenty of… Show more
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Something I have been pushing on for years is going to come to pass soon: We are going to make available an unlocked OS build for the Oculus Go headset that can be side loaded to get full root access.
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Old programmers instinctively recognize powers of two, but a younger generation of higher level programmers often don’t. I was pleasantly surprised when my young son was considering 16 and 32 ‘neat’ numbers. It was due to Minecraft.
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Replying to
person, but he reached out and said that it had always weighed on him, his latest business was doing well, and he wanted to pay me back. I found this moving after all this time, and I get to push a nice positive update into my personal “model of how people behave.”
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Watching YouTube often makes me feel good about humanity — so many people sharing lifetimes of skills and knowledge. Then ads come on that are so transparently snake oil, and I am saddened knowing that millions of people lack the critical thinking to see through them.
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I don’t think I had ever seen the term “malinformation” — something that is true, but likely harmful from some points of view. It popped up twice today in different contexts, and I have a visceral negative reaction to the concept.
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Concerning twitter.com/mtaibbi/status…
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It is 18 months after Connect 2021, and my $10k bet that “Roblox will not be surpassed in revenue by a decentralized, web based metaverse” is handily won. Does anyone know Shaw Walters? He seems to have disappeared from Twitter.
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A candle produces roughly the same amount of energy as a resting human — 80 to 100 watts, also consuming about the same amount of oxygen and producing the same amount of CO2. In an enclosed area, adding candles is about like adding people from an air quality standpoint.
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I had suggested to Lex that he edit it down to a more manageable size, but we didn’t even cover half the things we wanted to talk about. It might make sense to factor me into independent gaming/rockets/VR/AI phases, but everything winds up overlapping.
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Here's my conversation with John Carmack (@ID_AA_Carmack), legendary programmer & engineer. At over 5 hours, this is officially the longest conversation I've had on the podcast, and we can talk many more times. This was really fun and a huge honor for me. youtube.com/watch?v=I845O5
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Had a moment of panic when didn’t show up in my VR library today. Turns out you lose your freebie entitlements when you leave Meta. I am perfectly happy to give them an actual $29.99 for it! My scores remained, thankfully.
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I listened to audiobooks at 1.5x speed for years. I had tried 1.75x, but found it a bit too fast for comfort. Recently, I tried going up 0.1x every couple books, and now 1.9x is perfectly usable. This is a substantial benefit!
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AAA game dev often does a lot of analytics around where they lose players, and how “stuck” they get in various places. Amazon could provide similar info for kindle books, and authors could learn a lot from it — where are readers bored, and where are they binging?
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The old guard launch companies are on no trajectory to catch up to SpaceX. Continued denial is likely behavior, but it would be fun if they accepted it and took a hard turn away from conventional and tried some Crazy Plan C behavior — rotovators, SSTOs, heck, (space) Orion maybe!
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Employee levels in tech are a pretty big deal for compensation and evaluation, but are usually hidden from general view. I wonder if it might work better if they were visible like military ranks, so you knew at a glance something of what should be expected from a person.
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Replying to
As anyone who listens to my unscripted Connect talks knows, I have always been pretty frustrated with how things get done at FB/Meta. Everything necessary for spectacular success is right there, but it doesn't get put together effectively.
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I remain easily optimistic in the face of everything happening. Consider the most amazing person you personally know, by any quality metric you choose. Odds are that there are literally millions of their caliber in the world, which is plenty to build a bright future.
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I made a lifestyle change last year, adding a 3+ mile walk every day, rain or shine. It did take a bit out of my work hours, but covering 39 audio books and Great Courses has been valuable.
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I wonder what the trade offs are for piggy backing other instruments on low orbit comm sat constellations. You aren’t going to get a Keyhole aperture, but being able to have 24/7 coverage of anywhere seems valuable.
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The Mad Max post-apocalyptic muscle car esthetic needs to be updated — a bunch of jacked up Teslas recharging from solar panel farms works a lot better than a hacked together oil refinery.
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I looked up the budget for a small town library: Under $180k covers three employees, facility maintenance, and all the collections. Served population of 9k, so $20/resident. 13k visits, so around $14 per visit.
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It has been 18 years since I first talked with about his Falcon 1 plans. If this was a sci-fi novel it would have happened in a third the time, but aside from that, this is a golden age story playing out before our eyes. Scoffing at Mars should be getting hesitant.
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Crew Dragon has separated from Falcon 9’s second stage and is on its way to the International Space Station with @Astro_Behnken and @AstroDoug! Autonomous docking at the @Space_Station will occur at ~10:30 a.m. EDT tomorrow, May 31
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I skipped a generation of GPUs on my desktop. With the completely unoptimized model I am currently working on: Single Titan RTX: 156s 4090: 62s DGX Single A100: 42s
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It is hard for less experienced developers to appreciate how rarely architecting for future requirements / applications turns out net-positive.
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As someone who ends up building a lot of architectural and infrastructure code, there's one thing I cannot emphasize enough: do the simplest thing that works. Do not try to imagine future requirements, or support ill-defined potential use cases. It will always change later.
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Everyone knows that when you have similar code repeated several times that you should consolidate into a loop or function, but changing discrete variables into arrays and adding loops can have a small readability cost, so sometimes it can feel like a debatable choice for… Show more
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A lot of indie game devs want to do everything themselves, either by leaning on the asset store, or by becoming a polymath coder/artist/modeler/sound designer. It isn't impossible, and everyone has their favorite example, but it definitely isn't the high-probability path to \
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Freedom of speech is not “natural” for societies; speech has power, and reducing the agency of your opponents is an obvious play. I am happy that it is part of the US constitution, and I support defending it.
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So close! Green is the color of a copper rocket combustion chamber eating itself. That final part is well trod ground for SpaceX and won't hold things up; it looks like they succeeded in the areas that were really unknown.
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NEW: Unmanned SpaceX Starship test flight explodes during landing. There was no one on board the ship. abcn.ws/39WT56v
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Replying to
There is a strong temptation to find “just the right amount” of free speech, carving out what seems to be clearly harmful. I recognize that such an optimum can exist, but I am dubious about our ability to stand on exactly the right point on a slippery slope, so I tend absolutist.
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The notion that AGIs will “think 10,000 times faster than us” isn’t as obviously true as it seems at first glance. It is under appreciated that the self driving teams struggle to make their systems operate at barely real time rates, and they are not close to AGI systems. Step… Show more
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Rather than random programming problems and contrived tasks as interview tests, how about curating a list of issues on open source projects and judging candidates on how they attack them, turning the interview process into a public good?
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Replying to
I thought that the "derivative of delivered value" was positive in 2021, but that it turned negative in 2022. There are good reasons to believe that it just edged back into positive territory again, but there is a notable gap between Mark Zuckerberg and I on various strategic \
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When I started at Oculus, I didn't have any experience with the practicalities of video at scale, and I was a little surprised when I found that all the giant companies used the open source ffmpeg project in their backends. I expected some unique combination of commercial and \
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Using React (JavaScript) has turned out to be a bigger win for VR app development than I expected -- UI dev is several x faster than Unity.
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GPUs are built with more memory bandwidth, but higher latency and lower capacity than CPUs. AI accelerators could usefully make a different memory trade — the bandwidth of a GPU (or more), but the capacity of a CPU, in exchange for even higher latency. For inference, all the… Show more
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Unlike apparently so many people, I find twitter inspiring! So many smart people and interesting things — a little pruning required now and then, but it is more a problem of limiting the amount of quality versus finding it.
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A person is exposed to on the order of a billion words over their entire life through speech and reading. Modern large language models are fed hundreds of times that in the weeks of their training.
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If you can, build it. If you can’t build it, fund it. if you can’t fund it, champion it. If you won’t champion it, at least stay out of the way.
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"Don’t let the funding environment, the regulatory environment, or the culture stop you. Work around barriers or break through them, whatever it takes. The future is counting on you." rootsofprogress.org/how-to-end-sta
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