kens

28 ms·

421.
by kens 2y ago
It's a bit confusing. The plasma is created by RF, but the RF doesn't cause the antenna effect (nor do "chemicals"). The charged ions and electrons in the plasma are what cause the charge buildup. The wire acts as an ant
422.
by kens 2y ago
The antenna diodes are only relevant during manufacturing, when a metal line is connected on one end but not the other. ESD diodes on the other hand protect inputs against electrostatic discharge when the chip is in use.
423.
by kens 2y ago
Author here: I know this is a very obscure topic, but hopefully it will be interesting to some. Let me know if there are any questions...
424.
by kens 2y ago
One of my favorite papers is "A simple and convenient synthesis of pseudoephedrine from N-methylamphetamine" [1]. This is a satirical paper. Because pseudoephedrine (i.e. the good decongestant) is very difficult to obtain due to r
425.
by kens 2y ago
You could buy a 3-D printer from Stratasys in 1990, but it cost $178,000! The printing unit was $130,000 and the Silicon Graphics workstation with slicing software to run it was $48,000 more. So the technology was there, but two orders of m
426.
by kens 2y ago
The article lumps together writing characters slightly incorrectly and failing to come up with the character at all. For instance, the game show contestant wrote the word "烹" with one extra stroke, while the writer of the shopping
427.
by kens 2y ago
I find lots of solutions in binary, e.g. 3 and 5: 011 * 101 = 001111. Or if you don't like leading zeroes, 22*29: 10110 * 11101 = 1001111110 A general solution is 2^n+9 and 2^(n+1)-2 for n >= 5
428.
by kens 2y ago
I did a couple of practice runs before the video and got a bit faster, but there's a limit to how fast I can write down a page of 0's and 1's :-)
429.
by kens 2y ago
Author here. I don't know why this showed up on HN, but I can answer any questions...
430.
by kens 2y ago
In the NASA budget, -$230M is the "change from base year estimate" for the launch vehicle. In other words, the launch vehicle ended up being less than half the price of the initial budget estimate. (This is unusual; almost everyth
431.
by kens 2y ago
I was curious, so I looked up the budget. Development of Europa Clipper cost about $2.5 billion of which $1.1 billion was the spacecraft, $475M was payload, $200M was the launch vehicle (about $230M saved by not using SLS), $160M for ground
432.
by kens 2y ago
Unfortunately, no. Wealth data is usually very coarse (quartiles or quintiles) or one data point, which makes it hard to do most of the analysis that I'd like to do.
433.
by kens 2y ago
Rockefeller had $1.4 billion in 1937, which works out to $31 billion in 2024 dollars after adjusting for inflation. Ranking wealth by percentage of GDP doesn't really make sense. Otherwise, I could move to a small island like Tuvalu an
434.
by kens 2y ago
Yeah, the "controversial" filter kicked in because the post has more comments than upvotes. I reverse-engineered the HN algorithm a few years ago: https://www.righto.com/2013/11/how-hacker-news-ranking-re
435.
by kens 2y ago
Author here if anyone has questions. This is a bit different from my usual posts...
436.
by kens 2y ago
The IBM 1401 mainframe (1959) optionally supported pounds/shillings/pence (£sd) arithmetic in hardware. In those days, there were 12 pence in a shilling and 20 shillings in a pound, so arithmetic with UK money was non-trivial. (Th
437.
by kens 2y ago
Thanks! No worries, I just found it amusing to randomly encounter one of my die photos. I agree, it's remarkable how much complexity there is in a modern CPU compared to the early ones.
438.
by kens 2y ago
I'll point out that this is the same way that FPGAs implement arbitrary logic functions, as lookup tables (LUTs).
439.
by kens 2y ago
I read "Beyond: The Astonishing Story of the First Human to Leave Our Planet and Journey into Space" and found it very interesting. It is a detailed history of the early Soviet space program and Yuri Gagarin's flight.
440.
by kens 2y ago
As soon as someone loans us an FDAI...
441.
by kens 2y ago
I wasn't expecting to see my (uncredited) die photo of the 8008 processor in the middle of an article about P vs NP!
442.
by kens 2y ago
Author here for your mechanical computer questions... P.S. there are two more parts to the series, going into more details on the Globus, explaining the circuitry and the "algorithms": https://www.righto.com/2023&#
443.
by kens 2y ago
Here's a paper on a redundant display for military aircraft. Each LCD panel has redundant inputs, driver circuits, and power supplies. The two displays are built on a single LCD substrate, so there is no line between the two. https:&#
444.
by kens 2y ago
Thanks! Wait, you're the Linux/4004 guy, aren't you? That project was truly amazing.
445.
by kens 2y ago
The backup for the display is an integrated standby instrument system (ISIS), which combines several essential instruments into one small digital display. An ISIS typically has its own sensors and a battery backup, so it should stay operati
446.
by kens 2y ago
According to a paper on navigation sensors, commercial grade sensors have gyroscope drift of 0.1º/s (which is consistent with iPhone data), while navigation grade sensors have a drift of <0.01º/hour. I couldn't find specif
447.
by kens 2y ago
Author here if there are any questions...
448.
by kens 2y ago
I think the importance of Boolean algebra and computability theory to early computers is vastly overstated. I see no influence of computability theory on ENIAC, for instance. As for Boolean algebra, it seems more descriptive than useful for
449.
by kens 2y ago
There are multiple factors that limit the number of writes that FRAMs can handle: changes in crystal structure as Ti ions replace O, mobile ions collecting at grain boundaries, and something to do with 90º domains.
450.
by kens 2y ago
FRAM is like magnetic core memory in many ways, but the underlying principle is completely different: it is ferroelectric rather than ferromagnetic. And the materials are completely different.

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