Also worked with Soumith. The man is a legend, moves mountains and completely changed the course of my career because he liked something I wrote. No arrogance, no politics, just an extremely down to earth and chill guy who elevates everyone around him.
Just went through that thread, I can't believe this wasn't a team of like 20 people.
It's crazy to me that apple would put one guy on a project this important. At my company (another faang), I would have the ceo asking me for updates and roadmaps and everything. I know that stuff slows me down, but even without that, I don't think I could ever do something like this... I feel like I do when I watch guitar youtubers, just terrible
I hope you were at least compensated like a team of 20 engineers :P
Sometimes (often?), one very dedicated and focused person is better than a team of 20+. In fact companies would do well to recognize these situations and accommodate them better.
> Back then, Apple had a sabbatical program that encouraged (mandated?) employees to take six consecutive weeks off every five years.
This is really a good take. I can't imagine companies give sabbatical programs nowadays. You still have your vacations so JK took 12 weeks (OP mentioned in the same comment). It was a boon for any system programmer who needs to clear his mind or deepen his thoughts.
This is amazing. I wonder what it took to port MacOS from PowerPC to Intel. Every assembly language part must be rewritten, that’s for sure. Anything else?
Didn't Nextstep support x86 long before MacOS X was a thing? I assumed that they always had it compilable on x86 long before the switch (since Rhapsody supported it). I guess the user space stuff might have been trickier but probably not the kernel itself and surrounding components.
Yeah but from what I read from the Quora answer, it sounds like JK did it from scratch? I could be wrong though. I just wonder how much effort is supposed to be put into such a project.
Likely a few foundational technologies that have had significant improvements/reimplementations from Rhapsody like the scheduler/threading infrastructure, memory management, Quartz, Carbon, Quartz.
How can you create a 'pressure differential' without deflecting some of the air away? At the end of the day, if the aircraft is moving up, it needs to be throwing something down to counteract gravity. If there is some pressure differential that you can observe, that's nice, but you can't get away from momentum conservation.
The pressure differential is created by the leading edge creating a narrow flow region, which opens to a wider flow region at the trailing edge. This pulls the air at the leading edge across the top of the wing, making it much faster than the air below the wing. This, in turn, creates a low pressure zone.
Air molecules travel in all directions, not just down, so with a pressure differential that means the air molecules below the wing are applying a significant force upward, no longer balanced by the equal pressure usually on the top of the wing. Thus, lift through boyancy. Your question is now about the same as "why does wood float in water"?
The "throwing something down" here comes from the air molecules below the wing hitting the wing upward, then bouncing down.
All the energy to do this comes from the plane's forward momentum, consumed by drag and transformed by the complex fluid dynamics of the air.
Any non-zero angle of attack also pushes air down, of course. And the shape of the wing with the "stickiness" of the air means some more air can be thrown down by the shape of the wing's top edge.
You can't, but you also can't get away from a pressure differential. Those things are linked! That's my main point, arguing over which of these explanations is more correct is arguing over what exactly the shape of an object's silhouette is: it depends on what direction you're looking at it from.
How can you create a pocket of 'lower pressure' without deflecting some of the air away? At the end of the day, if the aircraft is moving up, it needs to be throwing something down to counteract gravity.
Exactly. The speed phenomenon (airflow speeding up due to getting sucked into the lower pressure space above the wing) is certainly there, but it's happening because the wing is shaped to deflect air downwards.
The point isn't about how the low pressure is created just that the low pressure is a separate source of lift from the air being pushed down by the bottom of the wing.
No, what still matters (when explaining why the wing is shaped the way it is) is how the low pressure is created. In this case it's being pulled down by the top of the wing.
This sounds like a smart comment, but the main reason you shouldn't take in vitro studies as indicative of real medical outcomes is largely due to unknown bio availability when consuming realistic doses. However, this study shows that the concentration of erithritol is well above the concentration where they see negative effects in vitro when consuming a realistic dose.
In addition epidemiological studies have found associations between higher plasma erythritol and clotting/cardiovascular events. So, regular disclaimers about difficulty of establishing health science aside, I would disagree this should 'not influence behaviors'.
> However, this study shows that the concentration of erithritol is well above the concentration where they see negative effects in vitro when consuming a realistic dose.
Are you saying that when you eat a normal/largish amount of erithritol (say 1-10g), the concentration of erithritol in your brain is similar to what they tested on brain cells in vitro here?
Also, how can they make a link to stroke when testing in vitro?
The study used a concentration of 6mM erythritol. This would be the mean (“bulk”) concentration found in the body after drinking 2-3 erythritol-sweetened soft drinks. I can find several with 10+ grams of it per bottle/can.
Erythritol Concentration: 6 mM (0.006 mol/L)
Molar Mass of Erythritol: 122.12 g/mol
Water in human body: 42 Liters
Calculated Total Mass: 30.77 grams (0.006 * 122.12 * 42)
A) Erythritol has ~90% bioavailability. See note at bottom.
B) Is a reasonable assumption. See same note at bottom.
C) Erythritol damages the microvascular endothelial cells, which form the BBB. So it doesn't need to cross the BBB, because that's what it damages directly. The name of TFA's study is "The non-nutritive sweetener erythritol adversely affects brain microvascular endothelial cell function"[0].
N.B. Erythritol is known to pass through the BBB via diffusion, though that's somewhat limited by its partition coefficient (logP) of -2.3. It's a small molecule, so it's not blocked based on size.
Also, this study isn't "just one study". There's a large corpus of research accumulating data both in vivo and in vitro showing both that erythritol causes these problems, and demonstrating how. This was a very thoughtful and reasonable study. The main point of the study was to measure oxidative stress, nitric oxide (NO), endothelin (ET)-1, and tissue-type plasminogen activator (t-PA). Their dysregulation is already well-known to be directly linked to the health of brain blood vessels and shown to be quite relevant in the development of stroke.
Epidemiological studies involving thousands of patients first established a strong, independent link between higher blood levels of erythritol and an increased risk for events like heart attack and stroke[1]. Subsequent mechanistic studies then showed that erythritol makes blood platelets hyper-reactive and more prone to clotting, providing a direct link to thrombosis[2]
Also in response to:
> A) is certainly wrong.
A previous study gave participants 30g of erythritol orally and their serum concentration rose from 4 µM to 6,480 µM [3]. That's why this study chose 6mM - they didn't just do some napkin math and YOLO it - previous studies pointed the way after showing that "(A) is certainly right".
Evidence in vitro suggests enhanced platelet activity. Plasma levels of erythritol are sustained for >2d above thresholds associated with platelet hyper-reactivity after consumption of realistic doses.
I use artificial sweeteners, but prefer sucralose or anything else to erythritol. I actually don't understand why people still use it (often in 'health food' because it's seen as 'natural'), there are much safer options.
yeah, I used to work in the medical tech space, they love to tell you how much you should be in it for the mission and that's why your pay is 1/3 what you could make at FAANG... of course, when it came to our sick customers, they need to pay market rates.
You need to setup the problem for the llm. If I am getting an error, I can normally piece together the 10k lines of relevant code much more quickly than I can track down the bug.
If you see an error and can't immediately Cmd+Shift+F an error code or something and jump to the exact line of code that threw the error, that's an engineering problem.
In big companies, this is a bit slower due to the need to migrate entrenched systems and org charts into newer workflows, but I think you are seeing more productivity there too. Where this is much more obvious is in indie games and software where small agile teams can adopt new ways of working quickly...
What if the number of game critics just hasn’t increased, and since they can only play/review a fixed number of games each year due to time constraints, the number that they acclaim each year hasn’t grown? Not saying this is necessarily the case, just suggesting the possibility.
Has the amount of 95%+ reviews games-released increased though? And how much of that is due to the pandemic? Its anecdotal, but the game-dev discord I'm in has had a decent reduction in # of regulars since the tail end of the pandemic 24-25. And ironically, I was one of them until recently. I think people actually just had more time.
Hope him the best!