Ciro Santilli @cirosantilli 37

Please, use AsciiDoc and one page to rule them all.

Borrow from the Internet Archive for free: archive.org/details/supermenstory00murr

Initial chapters put good clarity on the formation of the military-industrial complex. Being backed by the military, especially just after World War II, was in itself enough credibility to start and foster a company.

It is funny to see how the first computers were very artisanal, made on a one-off basis.

Amazing how Control Data Corporation raised capital IPO style as a startup without a product. The dude was selling shares at dinner parties in his home.

Very interesting mention on page 70 of how Israel bought CDC's UNIVAC 1103 which Cray contributed greatly to design, and everyone knew that it was to make thermonuclear weapons, since that was what the big American labs like this mention should be added to: en.wikipedia.org/wiki/Nuclear_weapons_and_Israel but that's Extended Protected... the horrors of Wikipedia.

Another interesting insight is how "unintegrated" computers were back then. They were literally building computers out of individual vacuum tubes, then individual semiconducting transistors, a gate at a time. Then things got more and more integrated as time went. That is why the now outdated word "microprocessor" existed. When processors start to fit into a single integrated circuit, they were truly micro compared to the monstrosities that existed previously.

Also, because integration was so weak initially, it was important to more manually consider the length of wire signals had to travel, and try to put components closer together to reduce the critical path to be able to increase clock speeds. These constraints are also of course present in modern computer design, but they were just so much more visible in those days.

The book does unfortunately not give much detail in Crays personal life as mentioned on this book review: www.goodreads.com/review/show/1277733185?book_show_action=true. His childhood section is brief, and his wedding is described in one paragraph, and divorce in one sentence. Part of this is because he was very private about his family most likely note how Wikipedia had missed his first wedding, and likely misattribute children to the second wedding; en.wikipedia.org/wiki/Talk:Seymour_Cray section "Weddings and Children".

Crays work philosophy is is highlighted many times in the book, and it is something worthy to have in mind:

Cray's final downfall was when he opted to try to use a promising but hard to work with material gallium arsenide instead of silicon as his way to try and speed up computers, see also: gallium arsenide vs silicon. Also, he went against the extremely current of the late 80's early 90's pointing rather towards using massively parallel systems based on silicon off-the-shelf Intel processors, a current that had DARPA support, and which by far the path that won very dramatically as of 2020, see: Intel supercomputer market share.

They put a lot of expensive equipment together, much of it made by other companies, and they make the entire chip for companies ordering them.

Ciro's large dataset survey: Section "Survey of open source interactive plotting software with a 10 million point scatter plot benchmark by Ciro Santilli".

That makes Ciro Santilli most mad about this film is the fact that the dude was passionate about writing, and when he became a genius, rather than write the best novels ever written, he decided instead to play the stock market instead. This paints an accurate picture of 2020's society, where finance jobs make infinitely more money than other real engineering jobs, and end up attracting much of the talent.

Another enraging thing is how his girlfriend starts liking him again once he is a genius, and instead of telling her to fuck off, he stays with her.

The other really bad thing is the ending. He fixed the drug by himself? He scared off De Niro just like that?

IMDb: www.imdb.com/title/tt0161382/

This film is really good.

The IETF was a notable one: www.nytimes.com/2021/04/13/technology/racist-computer-engineering-terms-ietf.html

Oscillator made of an LC circuit.

First watch: Video "Oscillators: RC, LC, Crystal by GreatScott! (2015)"

The $U(1)$ unitary group is one very over-generalized way of looking at it :-)

Most commonly known as a byproduct radioactive decay.

Their energy is very high compared example to more common radiation such as visible spectrum, and there is a neat reason for that: it's because the strong force that binds nuclei is strong so transitions lead to large energy changes.

A decay scheme such as Figure "caesium-137 decay scheme" illustrates well how gamma radiation happens as a byproduct of radioactive decay due to the existence of nuclear isomer.

Gamma rays are pretty cool as they give us insight into the energy levels/different configurations of the nucleus.

They have also been used as early sources of high energy particles for particle physics experiments before the development of particle accelerators, serving a similar purpose to cosmic rays in those early days.

But gamma rays they were more convenient in some cases because you could more easily manage them inside a laboratory rather than have to go climb some bloody mountain or a balloon.

The positron for example was first observed on cosmic rays, but better confirmed in gamma ray experiments by Carl David Anderson.

The orthogonal group has 2 connected components:

It is instructive to visualize how the $\pm 1$ looks like in $SO(3)$:

As a result it is isomorphic to the direct product of the special orthogonal group by the cyclic group of order 2:

A low dimensional example:because you can only do two things: to flip or not to flip the line around zero.

Note that having the determinant plus or minus 1 is not a definition: there are non-orthogonal groups with determinant plus or minus 1. This is just a property. E.g.:has determinant 1, but:so $M$ is not orthogonal.