Test server Updated +Created
Alan Turing Updated +Created
Client (computing) Updated +Created
Computer research institute Updated +Created
Crystal Fire: The Birth of the Information Age Updated +Created
Data center Updated +Created
Local server Updated +Created
Server run on the current machine. That's how all websites are developed and born!
Mathematical notation Updated +Created
It is hard to decide what makes Ciro Santilli more sad: the usage of Greek letters, the invention of new symbols, or the fifty million alternative font styles used.
Only Chinese characters could be worse than that!
Simple DirectMedia Layer Updated +Created
This is a really good project. So fun to play around with. Low level IO part only like drawing to screen and handling keyboard inputs.
Allotrope of carbon Updated +Created
Audiovisual art Updated +Created
Commissioning of the Twelve Apostles Updated +Created
The Twelve Apostles were actually officially appointed by Jesus amongst his followers. It was not simply that they were the first followers. It was official rank.
Polymorphism (computer science) Updated +Created
Server form factor Updated +Created
AC Josephson effect Updated +Created
This is what happens when you apply a DC voltage across a Josephson junction.
It is called "AC effect" because when we apply a DC voltage, it produces an alternating current on the device.
By looking at the Josephson equations, we see that a positive constant, then just increases linearly without bound.
Therefore, from the first equation:
we see that the current will just vary sinusoidally between .
This meas that we can use a Josephson junction as a perfect voltage to frequency converter.
Wikipedia mentions that this frequency is , so it is very very high, so we are not able to view individual points of the sine curve separately with our instruments.
Also it is likely not going to be very useful for many practical applications in this mode.
Figure 1.
I-V curve of the AC Josephson effect
. Source.
Voltage is horizontal, current vertical. The vertical bar in the middle is the effect of interest: the current is going up and down very quickly between , the Josephson current of the device. Because it is too quick for the oscilloscope, we just see a solid vertical bar.
The non vertical curves at right and left are just other effects we are not interested in.
TODO what does it mean that there is no line at all near the central vertical line? What happens at those voltages?
Video 1.
Superconducting Transition of Josephson junction by Christina Wicker (2016)
Source. Amazing video that presumably shows the screen of a digital oscilloscope doing a voltage sweep as temperature is reduced and superconductivity is reached.
Figure 2.
I-V curve of a superconducting tunnel junction
. So it appears that there is a zero current between and . Why doesn't it show up on the oscilloscope sweeps, e.g. Video 1. "Superconducting Transition of Josephson junction by Christina Wicker (2016)"?
Ciro Santilli's Open Source Enlightenment Updated +Created
Firstly, in 2012, while he was at École Polytechnique, Ciro Santilli was introduced to LaTeX (thank God for French mathematical obsession), and his mind was blown:
Ha, so I can write my own books, and so can anyone, for free?
he though. Why isn't everyone doing that!
One particular event stood out: Ciro made a small change to his teacher's course material, who blessed be him (dude's a legend, Ciro just noticed he has some Chinese publications with another French dude, e.g. www.amazon.co.uk/高效算法-应试与提高必修128例-克里斯托弗-Christoph-Durr/dp/B078SJQPVK "High-efficiency algorithm competitions 128 examples", did he write it the Chinese himself?? Must be of course to complement the notoriously low French professor salaries), made it available, and then Ciro gave him back the .tex file. Ciro was just a bit worried about how the teacher would be able to tell what he had changed in the file to validate the change. The teacher just said of course, "no problem, I'll just use diff". Ciro had never heard of diff. Let alone Git of course, though yes, this was a bit early in Git's history version control systems had been around since forever of course. This was 2011 or 2012, about 4 or 5 years into a superior education curricula with various courses involving computers, some requiring quite a lot of "fill these empty functions" style programming. Education is a joke. Anyways, this was a prelude to exactly what Ciro wanted to do in OurBigBook.com. This might have been the one actually: webia.lip6.fr/~durrc/Iut/Notes580.pdf
Not long afterwards, Ciro started playing with Linux. Until then, Ciro had had some contacts with the mysterious operating system at university, and was a bit puzzled what the point of it was! He clearly remembers:
University should be forced to use only open source software and hardware in undergrad teaching courses by law BTW.
Then came an Ubuntu live disk on his own machine, and finally a measly 40GB dual book partition in a Microsoft Windows machine on a laptop. At first, it took a lot of time to learn all the crazy new terminal stuff! Yes, at this point, Ubuntu was already usable enough without the terminal, an accomplishment actually. But as a programmer, Ciro felt obliged to learn. Many hours were spent reading man pages at the library. But it all just felt so right, and sometimes powerful... true wizardry.
And ten years later, Ciro was seriously considering buying a computer without Windows pre-installed. He had not used Windows a single tie on a personal machine even once in those ten years!
Finally, to finish things off Ciro found two websites that changed his life forever, and made be believe that there was an alternative: Stack Overflow and GitHub.
The brutal openness of it all. The raw high quality content. Ugliness and uselessness too no doubt. But definitely spark in a sea of darkness.
Cosine Updated +Created
Food Updated +Created
Pair programming Updated +Created

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