Comments by "Lawrence D’Oliveiro" (@lawrencedoliveiro9104) on "Scott Manley" channel.

  1.  @shawnpitman876  Considering that most of our knowledge of the surface of Venus came, not from NASA, but from the USSR, kind of weakens your appeal-to-authority argument somewhat.
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  2.  @shawnpitman876  Once you resort to name-calling, that means you lose the argument.
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  3.  @SeanBZA  When did you do that? I look at something like SiFive, and they claim they can put together a chip implementation for you within weeks.
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  4. Actually, there are quite a few architectures in common use. Your wi-fi router is probably running a MIPS processor. SiFive is gathering momentum. And if you look at the world’s fastest supercomputers, you’ll see a few POWER machines near the top. What do these processors have in common? They all run Linux.
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  5.  @John.0z  Sorry, yes, I meant RISC-V. SiFive is just one of many companies embracing that architecture.
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  6. 1:45 Would it be bad taste to call that the “JFK Head-Shot Effect”? #TooSoon?
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  7. 6:55 Hey, I’m old enough to remember, back in the day, when Caltex would advertise that they had “Boron” in the petrol they sold. This was before I discovered it was an element. Never found out whether it was the actual element they put in, or it was just a brand name for some proprietary additive or other.
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  8. Ah, the questino ... the little question. Like the neutrino is the little neutron.
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  9. ... and yet another anecdote to add to the confirmation bias regarding superstitions around the number 13 ...
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  10. This is science! Remember, science is the process, not the product.
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  11. “JCL” was an IBM thing.
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  12.  @PhotoArtBrussels  You could have been thinking of “DCL”. That was originally only on VAX/VMS, but DEC brought a version of it to some of its PDP-11 operating systems as well. Was this in the early 1980s, by any chance?
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  13.  @PhotoArtBrussels  That would have been about the right time for DCL.
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  14. There was rather more than just 32 or 36. There were also 24-bit, 48-bit, and 60-bit machines, just to mention a few.
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  15. 6:55 No, you mean 3 batteries. You already said each one was made of 31 cells.
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  16.  @RCAvhstape  Would you entrust mission-critical functions to an OS that can only handle 26 drive letters?
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  17. Previous manned rockets were sometimes referred to as “firecrackers”, but a solid-fuelled rocket is very literally one.
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  18. Did you skip a “Long March 10”? If the Chinese were to omit a number, I would expect it to be 14.
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  19. Yes, there is truth in science. Truth is that which, when you stop believing in it, doesn’t go away.
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  20. 09:13 That crash happened just six weeks before Apollo 11 took off, I believe. Also, the LLTV, or “Flying Bedstead”, was such a beast to fly, that you needed a fair bit of training before you were allowed to train in it.
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  21.  @donjones4719  GMT is deprecated because it is unclear what it means. The wording of the official definition could make it equal to either UT1 or UTC. But given that those two could differ by up to 0.9 seconds, you can see why a space mission, in particular, would find it unwise to use such a reference.
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  22. That’s the easy part: you just fall, and when you find you can’t fall any more, that must be the ground. Or did you mean, find the ground and stay in one piece ... ?
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  23.  @rdfox76  But wouldn’t that take a whole lot more memory? Since there are an awful lot more places where it isn’t than where it is?
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  24.  @jessepollard7132  From the Cray-1 Hardware Reference Manual (published 1977), page 3-28: “The division algorithm that computes S₁/S₂ to full precision requires four operations: 1. S₃ = 1 / S₂ -- Reciprocal approximation 2. S₄ = (2 - S₃ * S₂) -- Reciprocal iteration 3. S₅ = S₁ * S₃ -- Numerator * approximation 4. S₆ = S₄ * S₅ -- Half-precision quotient * correction factor The approximation is based on Newton’s method. The reciprocal approximation at step 1 is correct to 30 bits. The additional Newton iteration at step 2 increases this accuracy to 47 bits.”
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  25.  @StevePemberton2  If you’re interested, look up the Friden calculators from the 1940s/50s. They could do multiplications and divisions by repeated addition/subtraction. Later models were electrically-driven.
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  26. Years of training, and I think also they had to follow written checklists, and of course Mission Control was always on the line. 90% of their training was how to deal with things going wrong.
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  27.  @t65bx25  Not sure what that sequence is supposed to do. In my terminal: CTRL-A -- go to beginning of line CTRL-C -- send interrupt CTRL-V -- escape next control character What kind of OS do you think we would use?
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  28. Imagine running out of space in ... space.
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  29. I recall a story from Carl Sagan that the very first pictures from the Viking landers were accidentally “colour-corrected” to make the sky blue. Then when they were fixed later, this naturally fed some conspiracy theorists’ paranoid fantasies, that the landers had never actually left the Earth... But yes, I think all probes (or at least all landers) sent out with cameras also have calibration plates that the cameras can be pointed at for reference. That way they know what kind of colour correction to apply.
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  30. Not to mention it was the other way round compared to the others.
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  31. I heard the inside of the Apollo capsule described as similar in size to a “station wagon”. So nothing from NASA (from that era) could be described as an “apartment building”, by any stretch. Except maybe the inside of Skylab ... Why the Americans never adopted a Soyuz-style design (like the Chinese did), with more room available to the crew in space while still weighing less overall, I’ll never understand ... Trivia question: why did Gemini have ejection seats? Both Mercury and Apollo had that abort rocket on top of the capsule, to get the crew away in case of a booster failure, while Gemini did not. Why?
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  32. Those delay lines would only have been needed on the French SECAM system. The Germans came up with a much simpler solution to NTSC’s colour problems (besides its inability to spell “colour”).
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  33. 6:10 “Looking fine right now” ... shows messages with 4 lines saying “Failed”, 1 saying “Error”, and the remaining 3 showing “Loss”.
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  34. That was the one part of the Apollo program with probably the most women involved.
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  35.  @jimbarino2  I remember an article which mentioned the apparent challenge of designing such a fuel pump ... until you realize that it only has an operating life of 10 minutes.
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  36. And what a worthy name, for something right out on the edge ...
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  37. The cross-your-fingers part isn’t over yet.
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  38. Has there been any engineering in the opposite direction? That is, ideas in fuel injectors being used to design better showerheads?
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  39. To be fair, it’s at the emptier end of the North Island. /me says hi from just about the centre of population of the entire country.
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  40. Yes, there are places in the Universe with worse service than Comcast ...
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  41. SIMH does all the PDPs, I would say. (Except the oddball ones which weren’t really computers.)
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  42. One odd thing is, Jim Blinn described bump maps in a paper published in 1978. Yet you don’t see the technique used, even into the 1990s. For example, there was a PC-based CG program called “KPT Bryce” that was very popular in the 1990s, and was used to produce a great many characteristically surreal landscapes/seascapes with strange shapes, bright colours and elaborately-patterned surfaces. Yet all that elaborate patterning didn’t change the fact that the surfaces remained completely smooth. It wasn’t until, say, the latter 1990s/early 2000s that the software started to support bump maps to try to add some texture to surfaces.
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  43. He was NASA director at the time of the fire that killed Apollo astronauts Ed White, Gus Grissom and Roger Chaffee. He took responsibility and resigned. For bonus points: why did Blue Origin name a rocket “New Shepard” (after the first American in space) and another “New Glenn” (after the third American in space) but none “New Grissom” (after the second American in space)?
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  44. That’s what a spacecraft orbit looks like on a map projection, if it’s not exactly in the plane of the equator.
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  45. It was a product of its era: Knuth was trying to be as architecture-agnostic as he could, because “decimal” computers were still a thing. I think in the later editions he threw all that rigmarole away.
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  46. After you casually throw in that remark about slowing down at the end ... never more has your signoff phrase “fly safe” been more apt, I think ...
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  47. You didn’t mention ullage—how to (re)start a rocket engine in zero gravity. But yeah, very informative. Great work.
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  48. I suppose I should clarify that the problem only happens with liquid-fuelled engines. Gas-fuelled ones will start just fine.
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  49. 4:38 I never (that I recall) was told that Galileo invented the telescope as such. Instead, he was told that such a thing had been invented in the Netherlands. Just from the second-hand description, he grasped the principle of the device, and created his own--which happened to be several times better than the original anyway.
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  50. Galileo’s telescope was immensely valuable to the Venetians he was living among at the time, not for military purposes, but for commercial ones--remember, they were just about the foremost trading nation in the world at the time. Being able to see ships coming to port from further away was a massive advantage in terms of figuring out which trading expeditions were about to discharge their cargoes. Timeliness is money!
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