Paging makes it easier to compile and run two programs or threads at the same time on a single computer.
For example, when you compile two programs, the compiler does not know if they are going to be running at the same time or not.
And thread stacks, that must be contiguous and keep growing down until they overwrite each other, are an even bigger issue!
But if two programs use the same address and run at the same time, this is obviously going to break them!
Paging solves this problem beautifully by adding one degree of indirection:
(logical) ------------> (physical)
pagingWhere:
As far as programs are concerned, they think they can use any address between 0 and 4 GiB (2^32,
FFFFFFFF) on 32-bit systems.The OS then sets up paging so that identical logical addresses will go into different physical addresses and not overwrite each other.
This makes it much simpler to compile programs and run them at the same time.
Paging achieves that goal, and in addition:
- the switch between programs is very fast, because it is implemented by hardware
- the memory of both programs can grow and shrink as needed without too much fragmentation
- one program can never access the memory of another program, even if it wanted to.This is good both for security, and to prevent bugs in one program from crashing other programs.
Or if you like non-funny jokes:
The ultimate high level of which is of course to program with:which is basically the goal of artificial general intelligence, especially according to The Employment Test definition of AGI.
The term has not always had that sense:sums it up.
automatic programming has always been a euphemism for programming in a higher-level language than was then available to the programmer
Raspberry Pi Pico W MicroPython example by 
Ciro Santilli 37 Updated 2025-05-09 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-05-09 +Created 1970-01-01An upstream repo at: github.com/raspberrypi/pico-micropython-examples
Our examples at: rpi-pico-w/upython.
The examples can be run as described at Program Raspberry Pi Pico W with MicroPython.
- rpi-pico-w/upython/blink.py: blink on-board LED. Note that they broke the LED hello world compatibility from non-W to W for God's sake!!!
- rpi-pico-w/upython/led_on.py: turn on-board LED on and leave it on forever
- rpi-pico-w/upython/uart.py: has automatic UART via USB. Any
print()command ends up on the Raspberry Pi Pico W UART! Is is just like with Micro Bit, must be a standard Micro Python thing. The onboard LED is blinked as a heartbeat. - rpi-pico-w/upython/blink_gpio.py: toggle GPIO pin 0 on and off twice a second. Also toggle the on-board LED and print to UART for correlation. You can see this in action e.g. by linking an LED between pin 0 and one of the GND pins of the Pi, and the LED will blink.
- rpi-pico-w/upython/pwm.py: pulse width modulation. Using the same circuit as the rpi-pico-w/upython/blink_gpio.py example, you will now see the external LED go from dark to bright continuously and then back
- rpi-pico-w/upython/adc.py: analog-to-digital converter. The program prints to the UART the value of the ADC on GPIO 26 once every 0.2 seconds. The onboard LED is blinked as a heartbeat. The hello world is with a potentiometer: extremes on GND and VCC pins of the Pi, and middle output on pin 26, then as you turn the knob, the uart value goes from about 0 to about 64k.
TODO why is it so hard to find anything non perturbative :-(
- www.youtube.com/channel/UCPHFUHiwbpMqC8ONxEICCiQ NanoNebula using raw Perl PDFL en.wikipedia.org/wiki/Perl_Data_Language (the Perl NumPy)
- www.youtube.com/watch?v=9TJe1Pr5c9Q "Interplay of Quantum Electrodynamics and Quantum Chromodynamics in the Nontrivial Vacuum" by CSSM Visualisation (2019)
On a quantum computer...:
- www.cornell.edu/video/john-preskill-simulating-quantum-field-theory-with-quantum-computer Simulating Quantum Field Theory with a Quantum Computer by John Preskill (2019)
- www.youtube.com/watch?v=Lln-C21u0U8 Quantum Simulation from Quantum Chemistry to Quantum Field Theory by Peter Love (2019)
CIA 2010 covert communication websites feedsdemexicoyelmundo.com JavaScript reverse engineering by Ciro Santilli 37 Updated 2025-05-09 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-05-09 +Created 1970-01-01The JavaScript of each website appears to be quite small and similarly sized. They are all minimized, but have reordered things around a bit.
For example consider: web.archive.org/web/20110202190932/http://feedsdemexicoyelmundo.com/mundo.js
First we have to know that the Wayback Machine adds some stuff before and after the original code. The actual code there starts at:and ends in:
ap={fg:['MSXML2.XMLHTTPck++;};return fu;};Further analysis would be needed.
A single line in the emission spectrum.
So precise, so discrete, which makes no sense in classical mechanics!
Has been the leading motivation of the development of quantum mechanics, all the way from the:
- Schrödinger equation: major lines predicted, including Zeeman effect, but not finer line splits like fine structure
- Dirac equation: explains fine structure 2p spin split due to electron spin/orbit interactions, but not Lamb shift
- quantum electrodynamics: explains Lamb shift
- hyperfine structure: due to electron/nucleus spin interactions, offers a window into nuclear spin
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!
Intro to OurBigBook
. Source. We have two killer features:
- 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-calculusArticles 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/derivativeVideo 2. OurBigBook Web topics demo. Source. - 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: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.
- 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
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
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. 
- Infinitely deep tables of contents:
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