Udacity Updated 2025-07-16
It is a shame that they refocused to more applied courses. This also highlights their highly "managed" approach to content creation. Their 2022 pitch on front page says it all:
for as few as 10 hours a week, you can get the in-demand skills you need to help land a high-paying tech job
they are focused on the highly paid character of many software engineering jobs.
But one cool point of this website is how they hire tutors to help on the courses. This is a very good thing. It is a fair way of monetizing: e-learning websites must keep content free, only charge for certification.
When TLB is filled up, older addresses are overwritten. Just like CPU cache, the replacement policy is a potentially complex operation, but a simple and reasonable heuristic is to remove the least recently used entry (LRU).
With LRU, starting from state:
  valid  linear  physical
  -----  ------  --------
> 1      00003   00005
  1      00007   00009
  1      00009   00001
  1      0000B   00003
adding 0000D -> 0000A would give:
  valid  linear  physical
  -----  ------  --------
  1      0000D   0000A
> 1      00007   00009
  1      00009   00001
  1      0000B   00003
Allegory Updated 2025-07-16
Robert Noyce Updated 2025-07-16
Superconducting magnet Updated 2025-07-16
Applications: produce high magnetic fields for
As of the early 2020s, superconducting magnets predominantly use low temperature superconductors Nb-Ti and Nb-Sn, see also most important superconductor materials, but there were efforts underway to create practical high-temperature superconductor-based magnets as well: Section "High temperature superconductor superconducting magnet".
Wikipedia has done well for once:
The current to the coil windings is provided by a high current, very low voltage DC power supply, since in steady state the only voltage across the magnet is due to the resistance of the feeder wires. Any change to the current through the magnet must be done very slowly, first because electrically the magnet is a large inductor and an abrupt current change will result in a large voltage spike across the windings, and more importantly because fast changes in current can cause eddy currents and mechanical stresses in the windings that can precipitate a quench (see below). So the power supply is usually microprocessor-controlled, programmed to accomplish current changes gradually, in gentle ramps. It usually takes several minutes to energize or de-energize a laboratory-sized magnet.
Non-linearity is needed otherwise the input energy would just make the state go to higher and higher energy levels, e.g. from 1 to 2. But we only want to use levels 0 and 1.
The way this is modelled in by starting from a pure LC circuit, which is an harmonic oscillator, see also quantum LC circuit, and then replacing the linear inductor with a SQUID device, e.g. mentioned at: youtu.be/eZJjQGu85Ps?t=1655 Video "Superconducting Qubits I Part 1 by Zlatko Minev (2020)".
We know that superfluidity happens more easily in bosons, and so electrons joins in Cooper pairs to form bosons, making a superfluid of Cooper pairs!
Isn't that awesome!
ASCII art of a Force of Will, a famous and powerful Magic: The Gathering card first printed in 1996.
This is Ciro Santilli's personal favorite ASCII art he has found in the blockchain so far. Also Ciro could not find any other previous source of this, so there is some chance it is original. One can dream.
The choice of card is probably linked to the function of the card in the game of Magic: The Gathering. This card essentially prevents the opponent from casting a spell they are about to cast. The presumed intended meaning of this art is further accentuated by the old card type term "interrupt" (late renamed to "instant"), which suggests that "this ASCII art is an interruption to the normal monetary transactions of the blockchain".
One of also reminded of the prayer wars interruption attempts. We could not however identify anything specific that this ASCII art might have tried to interrupt besides the normal flow of monetary transactions.
If one goes full art critic mode, it is also tempting to draw a parallel between the card's "You may pay 1 life" alternative casting cost (as opposed to 5 mana, 3 and two blue, which is a very large cost for most games) as being a reference to the money spent by the uploader of the art to upload it.
TODO understand exactly how it was encoded and why it is so weird. The UUUU has a slightly weird encoding which we fixed by hand here TODO understand.
 -------------------------------------
|  Force of Will               3 U U  |
|  ---------------------------------  |
| |                  ////////////   | |
| |                ////() ()\////\  | |
| |               ///_\ (--) \///\  | |
| |        )      ////  \_____///\\ | |
| |       ) \      /   /   /    /   | |
| |    ) /   \     |   |  /   _/    | |
| |   ) \  (  (   /   / /   / \     | |
| |  / ) ( )  / (    )/(    )  \    | |
| |  \(_)/(_)/  /UUUU \  \\\/   |   | |
| .---------------------------------. |
| Interrupt                           |
| ,---------------------------------, |
| | You may pay 1 life and remove a | |
| | blue card in your hand from the | |
| | game instead of paying Force of | |
| | Will's casting cost.  Effects   | |
| | that prevent or redirect damage | |
| | cannot be used to counter this  | |
| | loss of life.                   | |
| | Counter target spell.           | |
| `---------------------------------` |
|                                     l
| Illus.  Terese Nelsen               |
 -------------------------------------
Figure 1. Source. A high resolution scan of the original card depicted in the ASCII art for comparison.
The following two ASCII transactions:
tx 0f05c47a8caafadecc10d70ba3bf010eaf6bb416b5e1ad7b01cf3445f5fb7a1c
I am. Therefore, I have come to be.

-- Hyena


tx e6d48f6912929a58a2ee30c13768058777d8547215c27109b5cb0724e7abaaba
Erich,
Bro, this looks excellent!!
-Duriel
suggest this ASCII art might have been uploaded by Figure "Erich Erstu", AKA Hyena, creator of cryptograffiti.info, a service which would have allowed uploading ASCII content to the blockchain.
The only other mention of "Duriel" in the blockchain is tx 140562ceb42fc8943fa52ccc0ddbb11ca2d88dae9b5240d7a4b46864538c515a which has some freedom of speech comments and gives the email:
Duriel@paystamper.com = 1HcuhfTAiQCt6KdMG2rZLXsTcKYj9nLDhS
paystamper.com was some other blockchain service from circa 2015:
j(-> 1EGa1izEFDHzEobDDQny73re9BwXdzhZvH <-
j(                 ,
j(                dM
j(                MMr
j(               4MMML                  .
j(               MMMMM.                xf
j(              "M6MMM               .MM-
j( h..          +MM5MMM            .MMMM
j( .MM.         .MMMMML.          MMMMMh
j( )MMMh.        MM5MMM         MMMMMMM
j(  3MMMMx.     'MMM3MMf      xnMMMMMM"
j(  '*MMMMM      MMMMMM.     nMMMMMMP"
j(    *MMMMMx    "MMM5M\    .MMMMMMM=
j(     *MMMMMh   "MMMMM"   JMMMMMMP
j(       MMMMMM   GMMMM.  dMMMMMM
j(        MMMMMM  "MMMM  .MMMMM(        .n
j(         *MMMMx  MMM"  dMMMM"    .nnMMMM
j(Mn...     'MMMMr 'MM   MMM"   .nMMMMMMM*
j(4MMMMnn..   *MMM  MM  MMP"  .dMMMMMMM""
j( ^MMMMMMMMx.  *ML "M .M*  .MMMMMM**"
j(    *PMMMMMMhn. *x > M  .MMMM**""
j(       ""**MMMMhx/.h/ .=*"
j(                .3P"%....
j(              nP"     "*MMnx
The transaction before the ASCII art tx 9b08c00ced2bca4525d74e82db9af2aec8ef213eb1c1bf68a48b6be929968332 starts with what is likely a "Legalize" and must be a Tor Onion service:
j(-> 1EGa1izEFDHzEobDDQny73re9BwXdzhZvH <-
but that address as is + .onion is invalid, TODO find the correct one.
Other marijuana plants can be found contained entirely in single transactions:
tx d338da06d13a21a296506c0c8cd8c8533ba8fa076ff5c2c1fd02a457aac3ef77 via cryptograffiti.info contains a marihuana plant followed by a complaint:
[ mirrored by http://dmabraham.info/ | moarrr ]
[ CryptoGraffiti: Donate BTC: 1MVpQJA7FtcDrwKC6zATkZvZcxqma4JixS ]
[ Latest News: EU/Greece chaos due to huge debts! ]
[ Bless! ]

{ Supa - https://bitcoin-otc.com/viewratingdetail.php?nick=supa }
William Robert Girdlestone
1535 Dingwall RD Apt 35
Courtenay
British Columbia
Canada
V9N 3S8

( https://bitcointalk.org/index.php?topic=575743.0 )
[ One of the lowest rated #bitcoin-otc users, owing me at least 10 BTC ]
[ Most likely much more with compounding interesting, but its all ]
[ written off as a huge loss to me. Never again deal with him! ]

There are unlisted articles, also show them or only show them.