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

  1. A brand-new Linux installation only requires one reboot. Last I heard, Windows requires about five.
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  2. And then there’s the fact that Windows loses its “New-OS smell” after just a few months, and needs reinstalling to get it back. Linux manages to stay fresh for much longer.
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  3. The Alien vs Predator of data interchange formats!
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  4.  @cromptank  I agree, that would be a better basis for setting the origin of a calendar than some fictitious birth date of some deity.
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  5. 7:08 Tell your colleague that rust isn’t magnetic.
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  6.  @nextlifeonearth  Only 3?? Luxury! I just counted the occurrences of “if(UNIX AND NOT APPLE)” in the build scripts for the Blender source code, and found 24 of them. Oh, and one “if(UNIX AND NOT (APPLE OR HAIKU))”. Yet another almost-but-not-quite-Unix system ... sigh ...
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  7.  @myguitardidyermom212  Reread what I said: “linguists found little or no use for his mathematical innovation”.
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  8. I have that C++ book. Not as useful as the actual language reference.
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  9.  @busimagen  Whoosh right back atcha.
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  10.  @kc9scott  Emacs, on the other hand, can go full graphical. You can even have clickable buttons in the middle of a text buffer.
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  11. 0:14 Another world map without 🇳🇿 ... sigh ... 0:37 Mentioning that he wants to ping Auckland just doubles the irony ... 0:44 ... OK, that’s a better map!
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  12. 3:57 Notice the switch numbers up to 21? (The other end starts at 0.) The 11/70, while it was a 16-bit machine with a 16-bit “virtual” address space, had 22-bit physical addresses. It think it could handle up to 2MiB of RAM, not 4MiB--the other half of the address space was for accessing I/O devices. But the software couldn’t access the entire address space directly — it had to keep fiddling memory-mapping registers to map various 8kiB blocks of the virtual space to desired blocks of the physical space.
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  13. 6:16 But then, if you are always filling rectangular areas rather than plotting individual points, then you will always be specifying the bounds of the areas to be filled. Thus, filling the whole playing field would mean filling a rectangle with corners (0, 0), and (width, height), not (0, 0) and (width - 1, height - 1). In other words, stop thinking of pixels as little squares. You want squares, think in terms of squares, not pixels.
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  14. 3:58 LEDs always need a resistor to stop them exploding, because they are prone to an effect known as “thermal runaway”. Most substances exhibit higher electrical resistance as their temperature rises. So as current flows through them and heats them up, this increases the resistance and acts as an automatic limit on how much more current can flow. LEDs exhibit the opposite behaviour: their resistance goes down as they heat up. Thus, if you put too much current through them, they heat up, lowering their resistance, and this means even more current flowing through, until they blow up, die etc.
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  15. Pascal was such a (relatively) small language, there were loads of compilers available, including ones you had to pay for and ones that you got for free. ALGOL 68, on the other hand, was much larger and more complex, so in our little neck of the woods, we never saw a compiler for it.
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  16. 10:35 Another kind of SIMD was introduced back in in the 1970s with the Cray machines. These had instructions which could act, element-by-element, on arrays of up to 64 elements with a single invocation. However, the operations were not performed simultaneously on every element, but were pipelined so that, after the initial instruction setup, the result elements would be churned out in succession very quickly. Contrast this with PowerPC Altivec (which I think predates Intel’s initially rubbish MMX), where operations are performed on all elements of the operand vector simultaneously. Note also that these vectors tend to be shorter than the Cray ones: a maximum of 4 elements (maybe 8 for small integers) is typical.
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  17.  @BruceHoult  Ho yus! He was the one who violated the terms of the “Don’t Make Larry Unhappy” licence!
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  18. 2:20 Unfortunately not “real” Windows. So it’s not even a “real” version of a “not real” OS. ;)
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  19. 6:09 Actually that was done using fixed-point (scaled-integer) calculations. Which were quite a pain to work with, but saved on floating-point hardware. As the hardware cost dropped, eventually it got to the point where the saving from leaving floating point out was negligible compared to the cost of programming without it. This was about the early-to-mid-1990s.
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  20. I would have to say, [citation needed].
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  21. I wonder why we don’t say at some point “OK, memory is now big enough, we can afford to go back to static RAMs now”. For example, you can easily pack in something like 64GiB of DRAM in a modern machine. If the same amount of circuitry can only amount to 16GiB of SRAM, that would still be very useful for many purposes. Also. SRAMs are faster to access, which is why they are used for high-speed caches. And think of the power saving!
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  22. Trivia question: what’s the difference between Smalltalk metaclasses and Python metaclasses?
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  23. 6:20 There is another way to write a command-line program, and that is to get its inputs from command-line arguments. Options passed by keyword can typically be specified in any order. This is typically more flexible than asking the user to type input lines.
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  24. In GUIs (0, 0) is typically at the top-left, anything touched by 3D graphics tends to put it at the bottom-left. It’s one of those minor annoyances, like the ordering of keys on the numeric keypad on computer keyboards versus telephones. Stick in the appropriate y-inverting scaling matrix somewhere and then just forget about it.
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  25. This is the baby version. Grown-up adults use sheepda calculus.
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  26. Which perhaps is why mainstream development is moving away from Windows. And why Microsoft is trying so hard to turn it into Linux.
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  27. The mistake lies in thinking that there is a “left” and “right” in memory. There isn’t, any more than there is a “top” or “bottom”. There are only numbers for bytes/words, and numbers for bits within a word. Spatial arrangement only applies when a human looks at a diagram. The usual reading order for English (or any other language using some variation of the Roman, Greek or Cyrillic alphabets) is left-to-right, top-to-bottom. If the bit numbers within a word should be in decreasing order from left to right, then, for consistency, shouldn’t we have word addresses decreasing from top to bottom?
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  28. Unix was the model for Linux, which today totally dominates the computing world. Once it became commercialized, Unix unfortunately became the field for a tussling match between a whole bunch of different vendors each trying to lock customers into their own proprietary variant. This fragmentation ultimately destroyed Unix. But oddly enough, at the same time, Unix was also the core nursery for the Free Software/Open Source movement, among other things the GNU project for creating a Free operating system. This is where Linux began. So Unix was very much the launching pad for what became the heart and soul of the computing world today. Its spirit lives on.
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  29. Asterisk is fun. I set it up for a client quite a few years ago, and even did some custom programming for it. That was an audio-only application, to replace analog phone calls.
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  30. 9:00 “Sheer speed” of IBM’s hardware!? Somewhere, Seymour Cray is going “HAHAHAHAHAHAHA!!!”
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  31. Don’t worry, everybody says it. ;)
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  32. OS/360 (the troubles with which started off The Mythical Man Month ) was written in assembler, but that didn’t stop it being complicated, buggy and slow.
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  33.  @gregoryfenn1462  I think the OP is referring to the thought processes, not something superficial like the accent.
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  34. Your own local branches are quite separate from remote branches, and you can have any number of each. “git branch -r” show remote branches, while “git branch” shows local ones. Remote branches are copies of other people’s public branches.
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  35.  @quangtung2912  What is the relevance of “precomputed” to what I said,. exactly?
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  36. 3:18 Presumably there are additional checks somewhere to ensure the packet length is sane. Otherwise you could fiddle those first four bytes to some random bizarre values and cause mischief that way. Because remember the MAC at the end has to be found via the packet length, so you can’t verify that until you are sure of the packet length!
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  37. TLS elbow-bump FTW!
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  38.  @johnfrancisdoe1563  Ðat’s what I þought.
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  39. 10:05 Yes, you could move directories to other partitions. I wouldn’t advise doing it to important OS directories while that OS is running, though. This is why SystemRescueCD was created. Keep a USB stick handy with a copy of it around.
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  40. Warning: Using TFS or Visual SourceSafe can be seriously harmful to your programmers’ productivity.
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  41. 7:41 UCSD Pascal was very influential. Most of the PC-based implementations were clearly inspired by it (e.g. variable-length strings, “univ” pointers).
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  42. You should ask yourself: is your project as large and complex as the Linux kernel? Over 20 million lines of code, thousands of new and changed code flowing in each day from over a thousand active contributors, with a new major, stable release coming out about every three months. And they manage it all with Git. I’m guessing that your particular project is a lot smaller than that. So if they can be so productive with Git, and you cannot, guess where I suspect the problem lies?
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  43. 3:00 Consider that the Unix kernels were themselves written in C. So a userland C program calling printf would pass control through the runtime library into the kernel, which would then do ... what? It can’t be language builtins all the way down, at some point there has to be actual reusable code to implement I/O.
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  44. Can’t handle regextion? 😅
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  45. There is failyr standard lambda-calculus notation, e.g. f = λx.x But I agree, that Haskell notation doesn’t make any sense to someone who doesn’t know Haskell.
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  46. I bought a Mindstorms kit, but I never used any of the proprietary software. I found the open-source NBC/NXC compiler, and built my code with that. I also wrote some of my own tools (in Python) to encode/decode the custom sound and graphics formats.
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  47. The reason for that should be obvious: it’s because Emacs was originally doing “windowing” on text terminals, before GUIs became commonplace. Rather than change their terminology, they simply added another nonstandard term, “frames”.
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  48.  @AndersJackson  ISO 8601 FTW! Also the national standard in Japan. For all their quirks, that’s one thing they did that makes sense.
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  49. Where does he get all that tractor-feed paper from? There’s nobody still making it, is there?
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  50. It was probably efficient taking the cost of the hardware into account. As in, with the technology available at the time, there was no way to increase the utilization efficiency by much without spending disproportionate amounts of money.
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