Hacker News: helpm33

New comment by helpm33 in "First-principles study on the electronic structure of Pb10−xCux(PO4)6O (x=0, 1)"

helpm33 — Tue, 01 Aug 2023 17:28:12 +0000

Well, a real experimental system is a quantum computer that 'calculates' the emerging behavior in real time. Sorry, that was needlessly sarcastic---actually, you have a good point there: it's ironic that we used digital computers to simulate quantum systems, and now we're beginning to use quantum computers to calculate digital properties (like decryption, etc), whereas it would be interesting to actually use quantum computers to calculate quantum systems such as electronic structure of many body systems. It's just that we're nowhere near that yet.

New comment by helpm33 in "US Department of Energy: Fusion Ignition Achieved"

helpm33 — Wed, 14 Dec 2022 01:41:08 +0000

3.15 MJ is equivalent to 1.5 lb TNT, so it was quite a bang in their target chamber. Just for comparison, it's also just short of one kWh, so it would run an electric car for about three-four miles.

New comment by helpm33 in "Disabling the Intel Management Engine"

helpm33 — Wed, 26 Oct 2022 18:05:57 +0000

If you're using Intel architecture, it needs at least some SMM: it is used on startup (initial hardware configuration) and often during power management events (CPU clock scaling, hibernation, etc). The article mentions that they disable most but not all of SMM, for those reasons.

New comment by helpm33 in "The origin of the strong form of superconductivity"

helpm33 — Thu, 22 Sep 2022 17:30:35 +0000

I don't know the state of the art but I think that we can't even predict the static crystal structure of simple substances---e.g. when iron is BCC vs FCC. The first-principles simulation of dynamic properties of large quantum many body systems is just not feasible. It is possible that this may change dramatically when quantum computers arrive---currently we describe quantum systems by modeling them with discrete, classical computers, and quantum computers might turn out to model the relevant quantum processes directly.

New comment by helpm33 in "Why do you waste so much time on the internet?"

helpm33 — Fri, 06 May 2022 17:11:24 +0000

Yes, he eats one. Bag :)

New comment by helpm33 in "Show HN: Recipe search engine, built in vanilla PHP"

helpm33 — Fri, 06 May 2022 17:05:24 +0000

https://en.wikibooks.org/wiki/Cookbook:Table_of_Contents

New comment by helpm33 in "USB Cheat Sheet"

helpm33 — Thu, 05 May 2022 17:14:52 +0000

Multiple serial busses, each with its own clocking and buffer, so that the combined data is extracted synchronously at the end. The crosstalk is still a problem but there are ways around that: different twist rates for different pairs for instance.

New comment by helpm33 in "How should net metering affect your electric bill?"

helpm33 — Fri, 04 Feb 2022 05:05:31 +0000

You have to be careful using these burners in in-building enclosed spaces---they can produce carbon monoxide. They are really designed for open air use.

New comment by helpm33 in "Dip Switch USB Stick"

helpm33 — Thu, 03 Feb 2022 22:59:29 +0000

I had something like that hanging off a parallel port in a PC in 1990; it read the status bits of a printer port and booted accordingly. Could still do it today, via a $1 USB serial port's status bits.

New comment by helpm33 in "The Church of the Clocked Screws (2019)"

helpm33 — Fri, 03 Dec 2021 16:01:21 +0000

I always clock screws in the electrical wall plates, for a vertical slot.

New comment by helpm33 in "Authenticated Boot and Disk Encryption on Linux"

helpm33 — Wed, 29 Sep 2021 16:39:13 +0000

FWIW, TPM 2.0 can encrypt the TPM traffic, so the attack by physically sniffing the TPM (https://dolosgroup.io/blog/2021/7/9/from-stolen-laptop-to-in...) is no longer possible.

New comment by helpm33 in "Using a laser pointer and a matrix LED as a two-dimensional input device (2010)"

helpm33 — Mon, 13 Sep 2021 17:06:10 +0000

BBC Micro:bit has a 5x5 LED matrix that can be read by an analog GPIO, so you can play with reading back light levels.

New comment by helpm33 in "Reverse engineering software licensing from early-2000s abandonware"

helpm33 — Tue, 31 Aug 2021 21:08:41 +0000

boot windows safe mode, execute sysprep. This strips windows of hardware-specific drivers, so that qemu should have an easier time running it. The whole thing is crusty, and it may or may not work. It does change Windows, so make a copy and keep the original image unchanged.