esmi (u/esmi) - Readit News

esmi commented on How x86_64 Addresses Memory blog.yossarian.net/2020/0... · Posted by u/chmaynard

saagarjha · 6 years ago

Actually, Objective-C's tagged pointers mostly rely on malloc's alignment guarantees.

esmi · 6 years ago

Sure. Some software has to exist to make use of this system, for example something has to create the tag in the first place, and mall ic is a part of that, but the large address space is what makes them possible.

esmi commented on How x86_64 Addresses Memory blog.yossarian.net/2020/0... · Posted by u/chmaynard

esmi · 6 years ago

It’s a nice tutorial on base plus index addressing but from the title I expected a tutorial on pointer tags as x86_64 is what makes tags even possible, i.e. we have a 64b address space but not 2^64 memory locations.

https://www.mikeash.com/pyblog/friday-qa-2012-07-27-lets-bui...

And for ARM.

https://www.mikeash.com/pyblog/friday-qa-2013-09-27-arm64-an...

esmi commented on Manned fighter to face autonomous drone next year thedrive.com/the-war-zone... · Posted by u/onewhonknocks

amphitoky · 6 years ago

got more info on those chess games?

esmi · 6 years ago

It used to be fairly straightforward to beat a chess engine... in the 80s. https://www.chess.com/blog/FangBo/how-to-beat-an-80s-chess-c...

esmi commented on There’s plenty of room at the Top: computer performance after Moore’s law techrepublic.com/article/... · Posted by u/dsavant

keenmaster · 6 years ago

Robotic process automation (RPA) can really help boost the performance of enterprise software, and it is just starting to take off.

esmi · 6 years ago

Is it like Automator for enterprise applications?

http://macosxautomation.com/automator/

esmi commented on Every Computer System Is a State Machine blog.the-pans.com/state-m... · Posted by u/uvdn7

noodlesUK · 6 years ago

Surely it isn’t though? A state machine is generally considered to be a finite state automaton, isn’t it? Turing machines are substantially higher up the Chomsky hierarchy than finite state automata.

Edit: take finite out of it, and then I suppose it’s equivalent to a Turing machine, but it’s a weird use of terminology

esmi · 6 years ago

A digital computer is definitely a FSM. In fact, creating the state diagram of a simple calculator, and mapping that to digital logic by hand, and then building it on a breadboard used to be a staple of most introductory computer architecture courses. Now they just simulate everything. :)

This is the technique http://faculty.etsu.edu/tarnoff/ntes2150/statemac/statemac.h...

esmi commented on SpaceX successfully launches two humans into orbit nasa.gov/press-release/na... · Posted by u/tosh

ncmncm · 6 years ago

Don't limit cadence. Just tax transactions, and cadence will limit itself.

esmi · 6 years ago

I waffle on this one too. Institutions that do HFT have a huge capital cost and pay large fees before they even make their first trade. They also employ programmers, traders, etc. Basically, these taxes are going to need to sum to something really big to dissuade them. Too small, they ignore it. Medium, the market will just consolidate. Large, you'll stop HFT, but at what consequence? The probability of unintended consequences is high.

This is when I decide I don't really understand the market as well as I think, and I should stop solving the world's problems, and go back to designing circuits.

esmi commented on SpaceX successfully launches two humans into orbit nasa.gov/press-release/na... · Posted by u/tosh

andrepd · 6 years ago

Eh, that's a really sad thing to optimise for, don't you think? Revealing of a broken incentive system. I'd prefer if HFT practices were banned.

esmi · 6 years ago

Personally I waffle on this myself. My instinct tells me it’s bad but then I try to decide what trading cadence I would limit it to. Assume there is a CEO who wants to do something nefarious to manipulate the stock price. If they make a decision how fast can a company actually act on it? Would or could they make the company act on 1 hour boundaries? Even if we limited trades to once per week is that the long term we want a CEO to consider? At what time frame does a stock stop being a stock and convert to something else? Then I decide even by minute trading is not really something that management can even consider, even if they want to, so there is really no point to artificial limits imposed by law and take a more laissez faire attitude.

esmi commented on A 1/48 scale model of the SpaceX Falcon Heavy rocket bps.space/falcon-heavy... · Posted by u/pmorici

NikolaeVarius · 6 years ago

Majority of engineers with a degree are useless right after graduation. Its a ton of random math that (most) of which you don't use again since you use modeling software.

Source: Did Aero

Someone doing this as a Amateur can damn well pick up whatever they need to.

esmi · 6 years ago

> Its a ton of random math that (most) of which you don't use again since you use modeling software.

You absolutely need that math because you need to know when the modeling software is giving the wrong answer. You’re supposed to do quick and dirty calc by hand (ok fine I use mathematica) in a simplified system, then you refine with numerical software and compare the two. It’s shockingly easy to get the wrong answer with numerical CAD.

esmi commented on Analysis of 200M tweets discussing coronavirus suggests 45%-60% come from bots marketwatch.com/story/abo... · Posted by u/nixtaken

yalogin · 6 years ago

Why does Twitter allow bots to tweet? If a researcher can determine that a tweet came from a bot, can twitter not do that?

esmi · 6 years ago

> If a researcher can determine that a tweet came from a bot

That condition is the key. Are you sure they can do that? It’s very tough to do with certainty.

esmi commented on “Maxwell's equations of software” examined (2008) righto.com/2008/07/maxwel... · Posted by u/lelf

tromp · 6 years ago

It's not directly comparable, since this Turing Machine is not a self-interpreter in the sense of interpreting arbitrary programs in a language of Turing Machines.

esmi · 6 years ago

First off, I admit I didn’t do my homework so I have no idea what I’m talking about, but couldn’t the Turing machine make a Turing machine interpreter and therefore be a self interpreter? It is universal, no?

u/esmi

KarmaCake day490December 18, 2013View Original