It was an issue of fundamentally differing directions.
In the mid-2000's, Sun decided to take SPARC towards designs with many small SMT cores. In the era of single-core processors, the UltraSPARC T1 had 8 cores x 4 threads per core. This was at the same time Intel released the Pentium 4 with hyper-threading, so it was an industry trend.
This of course works great for very specific applications, particularly considering efficiency, but is awful for others. Scientific computation was especially bad because the T1 had only one FPU for 8 cores.
Fujitsu's SPARC64 didn't go in this direction, and stayed with a conventional design (2 way SMT at most). Sun realized this and started to also sell the Fujitsu SPARC64 for customers who couldn't use the thread level parallelism, an arrangement that lasted until the end.
The idea of lots of slow cores is still a thing today: Intel's Sierra Forest Xeon is 144 E-cores.
Like Boeing, there was organizational dysfunction leading to a direct safety issue.
During the development of the A380, the German and French sides were using different versions of the CATIA PLM software (i.e. CAD), which prevented people from looking at a single unified model of the plane. One concrete problem it caused was major problems with the wiring harnesses, which led to a 2 year delay in the program, and 3 early A380's which couldn't be sold. (Airbus kept one for test, the other two got sent to museums)
That manifested in this accident because the wing wiring was routed through the engine disk burst axes (a hazard which is explicitly accounted for) with insufficient redundancy. That created the dangerous situation where they couldn't turn off the engine after landing.
The vastly preferable situation was to have redundant wiring that properly complied with regulations, which was retrofitted in an airworthiness directive (safety recall) after the accident.
They also required engine software that detected the sudden increase in speed associated with a shaft break and automatically cut fuel.
Sort of. Rolls Royce voluntarily developed this software modification in response to learning that their reasoning about it never being able to happen was incorrect and being unable to concretely account for how it happened. EASA, which was not even the relevant safety authority for this incident, upon learning of its existence, only then required it to be installed on all A380 Trent 900 engines.
> I've heard a theory that it has to do with genetics and lower eye sensitivity.
Might be.
But I expect that -as you said- it's cultural, rather than biological. One's sense of color is amazingly adaptable [0], but when I do a side-by-side comparison, I find that I strongly prefer the "noontime sun" color to the "incandescent bulb orange" color. As a bonus, the "noontime sun" whitepoint is pretty close to the whitepoint of my monitors, so white things on the screen are very nearly the same color as white things on my desk.
[0] Go play the game "Return of the Obra Dinn" for like an hour straight, and then be amazed at how off your understanding of what black is has become.
Is it by deliberate choice or something like availability? I come across enough people who don't seem to notice the difference at all, or at least until it's directly pointed out.
Had a ton of issues with the original Cree bulbs. They underglued the glass bulb and it came off with thermal cycling. They also put the LEDs on a metal core PCB they bent into ~10-gon tower. On the bends, the traces apparently would crack which led to overheating and a burn spot.
Cree is now no more; the bulbs are just a brand for FEIT who imports the same unreliable Chinese white-label bulbs.
Philips Hue. I've had issues with color ones, the White + Ambience ones are fine. (Makes sense as they omit the color section)
Hue is basically the only bulbs not being sourced from the same couple of white label manufacturers. Philips/Signify's rapidly shrinking line of dumb bulbs are being sourced from there too.
Never buy filament style bulbs. They are universally unreliable because of poor thermals with the emitters.
My OG gray Philips lasted more than a decade constantly on. It was still working at the end but I noticed the yellow remote phosphor plastic panels were disintegrating with a web of cracks. Underneath, the plastic surrounding the LEDs had turned brown: the polymers had photodegraded.
Fan blade failures are supposed to be contained. Turbine disk failures are not. This leads to several characteristics: disks are life-limited parts where they must be removed after so many cycles, no fuel tanks are within the burst axis of disks, and the flight ceiling of airliners is dictated by the fact that you can get holes and the cabin can (at >1e-9/flight hour) rapidly depressurize.
Candles are useful when oxygen has been consumed because of respiration or a fire. They're not useful in a leak.
Conservation of mass: if a cubic meter of air escapes, that's 1.25 kg, and you need at least that much in candles. (You actually need 2 kg because the candle isn't solid oxygen)
There's ultimately 1.2 t of atmosphere on the ISS. This will also result in a pure oxygen atmosphere, which is dangerous. You need nitrogen.
I think you're double counting; you need 1.25 kg of oxygen and nitrogen combined to replace 1 cubic metre of air.
1.2t of candles doesn't seem like an unreasonable amount of extra payload if they would really be valuable in an emergency. The ISS weighs 400 tons and a napkin estimate says it has had 1000 tons of resupply missions. The candles have a shelf life of 10+ years.
You need 1.25 kg of gas. Candles don't consist solely of oxygen, the ones the Russians use utilize lithium perchlorate (LiClO4). When they finish burning, you are left with a lithium chloride ash (LiCl), which will be 40% mass of what you started with.
It works out to be more efficient, at least in terms of mass, to send up large tanks of compressed gas instead.
NASA used pure O2 in space until the end of the Apollo program, but the Shuttle and later used the same air we breathe today, 1atm 80% N2/20% O2. Note that in space, the pure O2 was at 0.4atm, so roughly twice the oxygen partial pressure, but only slightly more dangerous than the air we are breathing now. (You need about 0.4atm to keep your lungs from collapsing, so that's the lower limit.)
Why the difference? It's a question of what risks you were most afraid of. Even today, every single spacewalk is done at 0.4atm pure O2- trying to do a spacewalk at 100kPa even the strongest man in the world would have trouble bending his arms- so before a spacewalk the astronauts need to spend several hours pre-breathing pure O2 to get all the nitrogen out of their bloodstream before they can do a spacewalk. The Apollo program thought it was safer if the astronauts could do a spacewalk at literally any point in the mission, so that's what the spacecraft was designed around.
On the other hand, for long duration spaceflight, introducing a different pressure and atmosphere is just another potential source of health problems. Even today, the largest source of information on how human bodies last under 0.4atm pure O2 is the three Skylab missions from 1973-1974. And so the Soviets- who were always more interested in space stations than the moon- and NASA during the Shuttle era went with the atmosphere that seemed like it offered less health risks for people staying on a space station.
Okay, so what about the Apollo 1 fire? To speed up testing, Apollo 1 did two tests at the same time: the Plugs-Out Test, where the astronauts were in the spacecraft with everything running and practicing their countdown, and the Overpressure test where they pressurized the spacecraft to 1.4 atm (to mimic the pressure differential in outer space). And they did it with pure O2. So you had all of these electronics running in an environment at 1.4atm pure O2. And that was incredibly dangerous, in a way that actual spaceflight, a mere 0.4atm O2, was not. But it was just a test, another in a long string of them, and no one involved ever really analyzed it as a potential hazard.
After Apollo 1 a few things were changed: one was that they did the Plugs Out test and the Overpressure test at different times, and a lot of stuff was turned off for the Overpressure test. Another was that the Apollo capsule at takeoff was 1atm 80/20 until a couple of minutes into flight, when it dumped the cabin atmosphere overboard and replaced it with pure O2 at 0.4atm. That's why the astronauts carried little packs in their arms in all the pictures of them getting into the spacecraft, that's the pure O2 tank that they were breathing off of until they could switch to the atmosphere in the cabin after it was replaced.
They breathe a normal mixture of O2 and nitrogen at 1 atmosphere of pressure. A pure oxygen environment is horrifically dangerous if fire ever breaks out.
And the 1961 fire that killed cosmonaut Valentin Bondarenko in an altitude chamber. The Soviets covered it up until the 1980's, so NASA made the same mistake.
Because it's not an actual investment and can't run out. Like US Social Security and many other national schemes, the UK is pay-as-you-go. Money coming in is immediately paid out.
Any funds lying around are supposed to be for temporary imbalances, but became significant due to a major demographic imbalance: the Baby Boom.
In the mid-2000's, Sun decided to take SPARC towards designs with many small SMT cores. In the era of single-core processors, the UltraSPARC T1 had 8 cores x 4 threads per core. This was at the same time Intel released the Pentium 4 with hyper-threading, so it was an industry trend.
This of course works great for very specific applications, particularly considering efficiency, but is awful for others. Scientific computation was especially bad because the T1 had only one FPU for 8 cores.
Fujitsu's SPARC64 didn't go in this direction, and stayed with a conventional design (2 way SMT at most). Sun realized this and started to also sell the Fujitsu SPARC64 for customers who couldn't use the thread level parallelism, an arrangement that lasted until the end.
The idea of lots of slow cores is still a thing today: Intel's Sierra Forest Xeon is 144 E-cores.
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