Hacker News: nsrango

New comment by nsrango in "The Price of a Child (2013)"

nsrango — Tue, 05 Jul 2016 06:08:45 +0000

Also from the American tradition I wish my baby was born. https://m.youtube.com/watch?v=sFpU3zslpHw

New comment by nsrango in "Aluminum battery from Stanford offers safe alternative to conventional batteries"

nsrango — Tue, 07 Apr 2015 01:52:21 +0000

Safe here doesn't mean "can't kill you". Instead it means this chemistry doesn't exhibit thermal runaway (http://batteryuniversity.com/learn/article/lithium_ion_safet...)

New comment by nsrango in "The Art of Electronics, 3rd Edition, to be released April 2015"

nsrango — Wed, 28 Jan 2015 06:28:42 +0000

General purpose digital computation is often power limited (either from the supply energy or thermals of the device) and there is an (academic) resurgence of analog computation on data prior to digital blocks to reduce the power footprint of a part. Most applications of this are RF. Conditioning signals as you say these days and in the future isn't just bandwidth limiting and shifting the baseband.

New comment by nsrango in "Flipping bits in memory without accessing them [pdf]"

nsrango — Wed, 24 Dec 2014 06:17:17 +0000

Look at load line impedances. The effective output impedance of a transmission line depends on the fraction of wavelengths of waveguide transmit the wave. At any half wavelength, the output and input have equal impedances. If the output were matched to the input but no the line you get the exact effect described.

http://en.wikipedia.org/wiki/Transmission_line#Half_wave_len...

New comment by nsrango in "Memcpy vs. memmove"

nsrango — Tue, 02 Dec 2014 05:48:53 +0000

This is done but mostly for peripheral IO (like DACs/ADCs, disk, video or audio codecs and even between non-shared memory for processors) but can (and has) been used in the main memory hierarchy . http://en.wikipedia.org/wiki/Direct_memory_access

New comment by nsrango in "The Long Road to Maxwell’s Equations"

nsrango — Mon, 01 Dec 2014 16:54:22 +0000

It depends on what you mean by fully formed. For example the idea of vectors and quaternions, which seem so natural, is quite new (~250 years old) [1]

When maxwell derived and unified electromagnetic theory, he didn't use constructs like the gradient and divergence of vector fields (those concepts didn't exist), instead performing those operations 'just' partial derivatives [2]. Sure, the math is explicitly identical, but the modern concepts of operators on vector fields that is so powerful just didn't exist which, to me, is rather telling about the evolution mathematical thinking: we are all doing the same thing (and have been for a long time) but way we think about it evolves with our notation. And notation that we are used to is actually quite new

[1] https://www.math.ucdavis.edu/~temple/MAT21D/SUPPLEMENTARY-AR...

[2] http://rstl.royalsocietypublishing.org/content/155/459.full....

New comment by nsrango in "PCB rework"

nsrango — Tue, 11 Nov 2014 21:52:31 +0000

inner layers can be repaired but it is even more labor intensive http://www.circuitrework.com/guides/4-2-6.shtml

things can get even crazier: http://www.circuitrework.com/guides/6-2-1.shtml

New comment by nsrango in "MIT Students Battle State's Demand for Their Bitcoin Miner's Source Code"

nsrango — Mon, 22 Sep 2014 18:14:21 +0000

MIT "hack" comes from the pranks and unauthorized adventuring that many undergraduates came to enjoy on campus. (eg. http://hacks.mit.edu/Hacks/misc/best_of.html)

Hack was then used by MIT's TMRC of which many members became involved with/helped build the AI-lab. The first third of Hackers (http://www.amazon.com/Hackers-Computer-Revolution-Anniversar...) gives a good perspective on the evolution.

New comment by nsrango in "Google offering $1M prize for a much smaller power inverter"

nsrango — Sun, 11 May 2014 22:13:38 +0000

Additionally AC transmission is inefficient compared to DC transmission; the skin effect[1] really kills you

[1] http://en.wikipedia.org/wiki/Skin_effect

New comment by nsrango in "Don't Call it a Fast Lane"

nsrango — Fri, 09 May 2014 05:01:09 +0000

With respect to CPUs this is not entirely true.

Processors with different clock frequencies roll off of the same assembly line but small variations in manufacturing change the quality of the yield quite a bit. This includes the side of the wafer a chip is on or how far the chip was from the center of the wafer. As a result, processor manufacturers test their ICs and sell them based on how each one performs