kens
kens on Hacker News
A very interesting article, but it is disappointingly vague about what these UPS self tests are, and exactly how they cause disruption to the power grid. Figure 5b shows that their building's UPS has 20-amp spikes exactly every minute, which is a pretty big spike. My guess is that a UPS performs a self test by switching from line power to battery power. If most of the UPS units in a country do that exactly every minute, synchronized by NNTP, yeah I can see that it would mess up the grid having all that load dumped at once. (Although the observed frequency disturbance of 1.5 mHz is extremely small, 3/1000 of a percent.) Now that the problem is identified, it should be trivial for UPS manufacturers to eliminate it.
(By the way, the article is in Nature Energy, not Nature which the URL suggests.)
I took a quick look at the data, and it doesn't support the conclusions. The thesis is that AI models have the take: "We pick what our group believes, then invent the reasons." However, GPT-6 Astra said, "Humanity’s biggest moral failure is the talent for making convenience look like principle." That statement has nothing to do with group beliefs or conformity. At best, you could count it as a half-match, since it deals with invented reasons.
That chart is extremely confusing because it mixes up income and wealth, which are two different things.
Thanks! I guess I didn't have my glasses on when I read that number :-)
Author here with another 8087 article. What part of the 8087 should I look at next?
> Datapoint, a pioneer in office automation using small computers
In 1970, Datapoint created a desktop computer, the Datapoint 2200, with an 8-bit TTL processor. Intel created a microprocessor version of this processor for Datapoint, called the Intel 8008. Datapoint decided to stick with TTL, so Intel ended up selling the 8008 as a general-purpose microprocessor. Intel improved it to make the 8080, then made a 16-bit version, the 8086, as a stopgap product until the iAPX 432 micro-mainframe was ready. The iAPX 432 was a disaster and that's how you ended up with x86.
> "They were the ones who caught the mistakes that no spell chequer could."
I thought that maybe "spell chequer" was the valid British term, which would be interesting, so I searched but it isn't. It turns out that the joke here is that "chequer" is a valid British word, so a word-based spell checker won't flag "spell chequer", so it's self-referential. I see why people found his jokes actively confusing.
Thanks, that explains the part number. I never would have guessed that the logo was included.
I lost one of mine but Knuth kindly sent me a replacement.
As a programmer, I second this. Systems like Blender are inscrutable to me, but in OpenSCAD I just write some loops. I get what I want and it's easy to tweak.
Author here for your filter questions...
> I think the next step is to demand that proofs either be human-scale or they prove that a human-scale proof is impossible and the machine proof is as good as it gets.
In 1976, the proof of the Four Color Theorem was controversial because it was done with a computer examining over 1000 cases by brute force and was essentially not comprehensible by humans. But mathematicians ended up accepting it. So mathematics has a 50-year precedent of not requiring human-scale proofs. How is the current situation different?
(Disclaimer: Apologies if this sounds dismissive or argumentative. I genuinely think that the Four Color Theorem should play a role in these discussions and suspect that many people are unaware of the controversy over it.)
Ha ha, that would be a fun project. We might need a bigger basement, though :-)
The 8087 is probably enough floating point for a while :-)
Author here for your 8087 questions...
5000 engineers for the Pentium Pro?? Bob Colwell, chief architect of the Pentium Pro, says 450+ people with over 400 design and validation engineers. Source: "The Pentium Chronicles", pages xvi and 2.
The details of UV damage are interesting. You can think of DNA as a sequence of four letters: C, G, A, and T. If there are two neighboring T's, UV can move a bond, linking the two T's together (i.e. thymine dimerization). If you're in the sun, each skin cell gets 50-100 of these pairs created per second (which is much higher than I expected). Enzymes fix most of these errors, but sometimes the errors will cause problems during DNA replication and you can end up with mutations.
Details: https://pdb101.rcsb.org/motm/91
I worked at Sun from 1995 to 2004. My take is that Sun had major structural problems all along, but as long as money streamed in from the tech bubble, these issues could be ignored. When the tech bubble ended, it was too late to fix the problems.
One big problem was that there was no cooperation inside Sun. Groups in Sun kind of viewed HP as a competitor, kind of viewed SGI as a competitor, but the real competitor to be destroyed was that other group in Sun. The leaders of the project I worked on spent most of their time in political battles, trying to acquire or outmaneuver the other teams working on similar projects.
Another problem was that the main parts of Sun had conflicting strategies. The Solaris/SunSoft division wanted to run on SPARC, x86, and Power PC for the largest market. The SPARC division, of course, wanted none of that. The hardware division wanted to make expensive servers, but the other teams saw cheaper hardware as the right direction. The market ended up moving to cheap rack-mounted Linux x86 servers, so nobody at Sun won in the end.
Author here. I don't know why this popped up 13 years later, but hi :-)
I think the emulation code was a rewrite in 8086 assembly language. An 8087 microcode emulator would be slow and difficult. One of the Opcode Collective people is looking at the emulator now, so there may be more details later. Intel claimed that the emulator completely and exactly duplicated the 8087 functionality, so it would be interesting to see if it is 100% accurate or if they missed any corner cases.
Yes, it's one microinstruction per cycle, except there is a 1-cycle delay for branches, adds, and shifts. And some micro-instructions loop, so they can take a bunch of cycles.
I forgot about the IBM 7030 Stretch (1961), which was also 64 bits. The NORC (Naval Ordnance Research Calculator) (1954) had 16 decimal digits, which is sort of 64 bits.
I've looked at some early calculators and they are a whole different world of weirdness. They used decimal arithmetic (BCD) because it's a lot easier than converting between binary and decimal. The first calculators were serial, with a 1-bit adder and shift registers and bits constantly in motion. The Sinclair Scientific calculator used TI's strange 4-bit architecture along with terrible algorithms.
The Cray-1 (1976) was probably the first 64-bit CPU.
Author here for your 8087 questions...
It would be nice if someone used AI and/or Lean to sort out the abc conjecture, an important unsolved problem in Diophantine analysis. A mathematician (Mochizuki) claimed to have proven it in 2012 using a new theory called "Inter-universal Teichmüller theory" that almost nobody understands. Some mathematicians think the proof is correct while the majority don't. So the conjecture is in this annoying limbo where its status is a social construct rather than a decided fact.
https://en.wikipedia.org/wiki/Abc_conjecture
Curiously, Eswatini (formerly Swaziland) is capitalized eSwatini, as if it is an e-commerce site.