University of São Paulo by Ciro Santilli 35 Updated +Created
Ciro Santilli studied there for a few years starting in 2007.
In retrospect, doing electrical engineering (and likey the other engineering degrees) felt like taking a trip to the 60s in the United States, due to both the subject matter, and how old the concrete buildings were!
This does not need to be a bad thing. It is in that era (and earlier) that much of the exciting foundations of the field were set, and there is great value in there is value in tutorials written by early pioneers of the field. Not that they were amazing at excting history lessons as they should be. But the course outline suggested that intent.
But that point of view must also be accompanied by the excitement of the great ongoing advances of technology (and impact they had in the past). And on that, they failed.
One day, one day, we will fix that.
Genesis block message by Ciro Santilli 35 Updated +Created
Inscription added by Satoshi Nakamoto on the Genesis block containing:
The Times 03/Jan/2009 Chancellor on brink of second bailout for banks
which is a reference to: www.thetimes.co.uk/article/chancellor-alistair-darling-on-brink-of-second-bailout-for-banks-n9l382mn62h wihch is fully titled:
Chancellor Alistair Darling on brink of second bailout for banks
The "Alistair" was slikely removed due to limited payload concerns.
Through the newspaper reference, the message proves a minimal starting date for the first mine.
And it hints that one of Bitcoin's motivation was the financial crisis of 2007-2008, where banks were given bailouts by the government to not go under, which many people opposed as the crisis was their own fault in the first place. A notable related stab is taken at Len Sassaman tribute.
We can extract the image from the blockchain ourselves by starting from: blockchain.info/block-height/0?format=json.
From that page we manually extract the hash 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f and then:
wget -O 0.hex https://blockchain.info/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f?format=hex
xxd -p -r 0.hex
and that does contain the famous genesis block string:
EThe Times 03/Jan/2009 Chancellor on brink of second bailout for banks
The JSON clarifies that the data is encoded in the script field of the transaction input:
{
      {
         "script":"04ffff001d0104455468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73"
The extra E (0x45 in ASCII) in EThe Times is just extra noise required by the script, we can break things up as:
04ffff001d0104 45 5468652054696d65732030332f4a616e2f32303039204368616e63656c6c6f72206f6e206272696e6b206f66207365636f6e64206261696c6f757420666f722062616e6b73
where:
  • 54 is T
  • the 04ffff001d0104 part just doesn't show up on the terminal because it is not made of any printable characters.
The initial 04 is OP_RETURN.
TODO what is actual the meaning of the ffff001d010445 part? @defango twitter.com/defango/status/1642750851134652417 comments:
04ffff001d0104 is a hexadecimal string. It is commonly used in the Bitcoin network as a part of the mining process. Specifically, it is used as the target value for a block to be considered valid by the Bitcoin network.
This value represents the level of difficulty required for a miner to generate a block that meets the network's criteria. The first four bytes, 04ffff, represent the maximum possible target value. The next three bytes, 001d01, represent the current difficulty level
while the final byte, 04, is a padding byte. In summary, this value sets the difficulty level for mining a new block in the Bitcoin network.
TODO the output of the transaction has a jumbled script, likely just a regular output to get things going, can't be arbitrary like input.
Arsenide compound by Ciro Santilli 35 Updated +Created

Pinned article: ourbigbook/introduction-to-the-ourbigbook-project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Video 1.
Intro to OurBigBook
. Source.
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
    Video 2.
    OurBigBook Web topics demo
    . Source.
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    • to OurBigBook.com to get awesome multi-user features like topics and likes
    • as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact