you’re calculating the sha256 (i think) hash of the previous transaction block’s hash plus your block of transactions. What’s making it proof-of-work though, is the stipulation that “the hash has to start with at least five zeroes”, with “five” being an adjustable difficulty value. To be able to get that specific hash an otherwise meaningless number (a “nonce”) is included, and by increasing this number by one you can change the hash value.
so basically, all these servers are running hash calculations on the same thing over and over again with a single number changing between runs until they get an “approved” hash value. whoever gets there the fastest gets their block added to the chain, then everyone else has to start over with that hash as the “previous” one.
It’s called “proof of work” because it’s difficult to find a suitable value, but it’s trivial to check that it’s correct. you just need the nonce. so by presenting that nonce to everyone, you’ve proved that you “did the work”.
as for the reason why they do this, if each block’s hash is dependent on the hash of the block before it, it means the entire chain is resistant to tampering. you can’t insert a block in the middle without recalculating the entire chain.
most of my hours are in 2. there was something very compelling about having a toy city with clearly demarcated areas to move around in. complete with shittons of easter eggs for pulling off weird stunts like ramping off of a subway station stairway and onto a roof.
the physics of the top-down GTAs just can’t be replicated in 3D, like how the tank just rolls over every vehicle in its path.
also the radion stations are insane.
i was unfortunately responsible for this one…
we developed a wireless communication protocol which was specified in an excel sheet, and it fell on us devs to implement the message types specified in the sheet. however since the specification kept changing we had to constantly update the message types in our tests to make sure they conformed. so i said “fuck it” and built a program that allowed me to “import” an excel file in a python program, which exposed all messages as classes that could be instantiated with automatic unit conversions. just drop the excel file of the day in the right place and run the test suite.
anyway that’s how the excel sheet became the formal API definition
the implication of einsteins mass-energy equivalence formula is mind-blowing to me. one gram of mass, if perfectly converted to energy, makes 25 GWh. that means half the powerplants in my country could be replaced with this theoretical “mass converter” going through a gram of fuel an hour. that’s under 10 kilograms of fuel a year.
a coal plant goes through tons of fuel a day.
energy researchers, get on it
hl2ep2 part 2