Engineer Updated 2025-07-16
Engineering Updated 2025-07-16
E notation Updated 2025-07-16
What do you prefer, 1 \times 10^{10} or 1E10.
Enthought Updated 2025-07-16
Erdős' conjecture on powers of 2 Updated 2025-10-27
Described at: arxiv.org/pdf/2107.12475.pdf where a relation to the Busy beaver scale is proven, and the intuitive relation to the Collatz conjecture described. Perhaps more directly: demonstrations.wolfram.com/CollatzSequenceComputedByATuringMachine/
Entropy Updated 2025-07-16
OK, can someone please just stop the philosophy and give numerical predictions of how entropy helps you predict the future?
The original notion of entropy, and the first one you should study, is the Clausius entropy.
Video 1.
The Unexpected Side of Entropy by Daan Frenkel
. Source. 2021.
Video 2.
The Biggest Ideas in the Universe | 20. Entropy and Information by Sean Carroll (2020)
Source. In usual Sean Carroll fashion, it glosses over the subject. This one might be worth watching. It mentions 4 possible definitions of entropy: Boltzmann, Gibbs, Shannon (information theory) and John von Neumann (quantum mechanics).
enwiki-latest-category.sql Updated 2025-07-16
dumps.wikimedia.org/enwiki/latest/enwiki-latest-category.sql.gz contains a list of categories. It only contains the categories and some counts, but it doesn't contain the subcategories and pages under each category, so it is a bit pointless.
The SQL first defines the table:
CREATE TABLE `category` (
  `cat_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `cat_title` varbinary(255) NOT NULL DEFAULT '',
  `cat_pages` int(11) NOT NULL DEFAULT 0,
  `cat_subcats` int(11) NOT NULL DEFAULT 0,
  `cat_files` int(11) NOT NULL DEFAULT 0,
  PRIMARY KEY (`cat_id`),
  UNIQUE KEY `cat_title` (`cat_title`),
  KEY `cat_pages` (`cat_pages`)
) ENGINE=InnoDB AUTO_INCREMENT=249228235 DEFAULT CHARSET=binary ROW_FORMAT=COMPRESSED;
followed by a few humongous inserts:
INSERT INTO `category` VALUES (2,'Unprintworthy_redirects',1597224,20,0),(3,'Computer_storage_devices',88,11,0)
which we can see at: en.wikipedia.org/wiki/Category:Computer_storage_devices
Se see that en.wikipedia.org/wiki/Category:Computer_storage_devices_by_company
so it contains only categories.
We can check this with:
sed -s 's/),/\n/g' enwiki-latest-category.sql | grep Computer_storage_devices
and it shows:
(3,'Computer_storage_devices',88,11,0
(521773,'Computer_storage_devices_by_company',6,6,0
There doesn't seem to be any interlink between the categories, only page and subcategory counts therefore.
Epic Rap Battles of History Updated 2025-07-16
Most of the videos are crap, but the following ones almost killed Ciro Santilli of laughter:
Monty Python has a few precursors to the "random famous people mixed together compting" format, although not in the rap fight format:
Video 3. Source. If you can understand the jokes, your philosophy level is pretty good. Like more than zero. Wiki page: en.wikipedia.org/wiki/The_Philosophers%27_Football_Match. Ciro loves how that page currently uses a standard footbal match template to describe the match!
Epsilon (letter) Updated 2025-07-16
Confusingly, in LaTeX:
  • \varepsilon rendered , is the default modern Greek glyph
  • \epsilon rendered is the lunate variant
Equations of motion Updated 2025-07-16
These are the final equations that you derive from the Lagrangian via the Euler-Lagrange equation which specify how the system evolves with time.
Erase SSD securely Updated 2025-07-16
You can't just shred individual sSD files because SSD writes only at large granularities, so hardware/drivers have to copy stuff around all the time to compact it. This means that leftover copies are left around everywhere.
What you can do however is to erase the entire thing with vendor support, which most hardware has support for. On hardware encrypted disks, you can even just erase the keys:
TODO does shredding the

Unlisted articles are being shown, click here to show only listed articles.