These are the final equations that you derive from the Lagrangian via the Euler-Lagrange equation which specify how the system evolves with time.
ELF Hello World Tutorial Minimal ELF file by 
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01It is non-trivial to determine what is the smallest legal ELF file, or the smaller one that will do something trivial in Linux.
Some impressive attempts:
ELF Hello World Tutorial Section vs segment by Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01- section: exists before linking, in object files.Major information sections contain for the linker: is this section:
- segment: exists after linking, in the executable file.Contains information about how each segment should be loaded into memory by the OS, notably location and permissions.
It is hard for complex organisms to evolve because longer DNA means longer replication time by Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01Because DNA replication is a key limiting factor of bacterial replication time, such organisms are therefore strongly incentivized to have very minimal DNAs.
Power, Sex, Suicide by Nick Lane (2006) 7 "Why bacteria are simple" page 169 puts this nicely:
Bacteria replicate at colossal speed. [...] In two days, the mass of exponentially doubling E. coli would be 2664 times larger than the mass of the Earth.Luckily this does not happen, and the reason is that bacteria are normally half starved. They swiftly consume all available food, whereupon their growth is limited once again by the lack of nutrients. Most bacteria spend most of their lives in stasis, waiting for a meal. Nonetheless, the speed at which bacteria do mobilize themselves to replicate upon feeding illustrates the overwhelming strength of the selection pressures at work.
Cool data embedded in the Bitcoin blockchain HHTT by Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01The Horrible Horrendous Terrible Tremendous Mining Pool inscribed a few cute Coinbase messages during their operation in 2012-2013.
Many of their messages also mention
SockThing, which was part of their mining infrastructure:Starting from their very first ASCII transaction on block 197602 (2012-09-07), there is what seems to be a poem spread across several transactions. Some of the lines are repeated, presumably because they didn't update the current line to a new line and so mined the same thing multiple times:The sentences are not very coherent together, perhaps this is because lines were chosen by different miners one at a time.
I am a pretty princess
covered in mud and blood
water with stuff in it
like everything else that wiggles or jiggles
screaming might not be your waY
see no reason to operate otherwise since
came into the world naked, wet and screaming
but silence will never be mine
until I am dead
but the smell will also give that away
gather all my things
load them in a big boat
airlift that to Kansas
and light it on fire
drop it from 7,000 feet
then railgun my corpse straight down
Cool data embedded in the Bitcoin blockchain Hidden surprises in the Bitcoin blockchain by Ken Shirriff (2014) by Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01 Compile MicroPython code for Micro Bit locally on Ubuntu 22.04 with your own firmware by Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01
Ciro Santilli 37 Updated 2025-07-16 +Created 1970-01-01TODO didn't manage from source Ubuntu 22.04, their setup bitrotted way too fast... it's shameful even. Until I gave up and went for the magic Docker of + github.com/bbcmicrobit/micropython, and it bloody worked:
git clone https://github.com/bbcmicrobit/micropython
cd micropython
git checkout 7fc33d13b31a915cbe90dc5d515c6337b5fa1660
docker pull ghcr.io/carlosperate/microbit-toolchain:latest
docker run -v $(pwd):/home --rm ghcr.io/carlosperate/microbit-toolchain:latest yt target bbc-microbit-classic-gcc-nosd@https://github.com/lancaster-university/yotta-target-bbc-microbit-classic-gcc-nosd
docker run -v $(pwd):/home --rm ghcr.io/carlosperate/microbit-toolchain:latest make all
# Build one.
tools/makecombinedhex.py build/firmware.hex examples/counter.py -o build/counter.hex
cp build/counter.hex "/media/$USER/MICROBIT/"
# Build all.
for f in examples/*; do b="$(basename "$f")"; echo $b; tools/makecombinedhex.py build/firmware.hex "$f" -o "build/${b%.py}.hex"; doneThe pre-Docker attempts:
sudo add-apt-repository -y ppa:team-gcc-arm-embedded
sudo apt update
sudo apt install gcc-arm-embedded
sudo apt install cmake ninja-build srecord libssl-dev
# Rust required for some Yotta component, OMG.
sudo snap install rustup
rustup default 1.64.0
python3 -m pip install yottaThe line:warns:and then the update/
sudo add-apt-repository -y ppa:team-gcc-arm-embeddedE: The repository 'https://ppa.launchpadcontent.net/team-gcc-arm-embedded/ppa/ubuntu jammy Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.sudo apt-get install gcc-arm-embedded fails, bibliography:Attempting to install Yotta:or:was failing with:Running:did not help. Bibliography:
sudo -H pip3 install yottapython3 -m pip install --user yottaException: Version mismatch: this is the 'cffi' package version 1.15.1, located in '/tmp/pip-build-env-dinhie_9/overlay/local/lib/python3.10/dist-packages/cffi/api.py'. When we import the top-level '_cffi_backend' extension module, we get version 1.15.0, located in '/usr/lib/python3/dist-packages/_cffi_backend.cpython-310-x86_64-linux-gnu.so'. The two versions should be equal; check your installation.python3 -m pip install --user cffi==1.15.1From a clean virtualenv, it appears to move further, and then fails at:So we install Rust and try again, OMG:which at the time of writing was
Building wheel for cmsis-pack-manager (pyproject.toml) ... error
error: [Errno 2] No such file or directory: 'cargo'sudo snap install rustup
rustup default stablerustc 1.64.0, and then OMG, it worked!! We have the yt command.However, it is still broken, e.g.:blows up:bibliography:
git clone https://github.com/lancaster-university/microbit-samples
cd microbit-samples
git checkout 285f9acfb54fce2381339164b6fe5c1a7ebd39d5
cp source/examples/invaders/* source
yt clean
yt buildannot import name 'soft_unicode' from 'markupsafe'AMD Founder Jerry Sanders Interview (2002)
Source. Source: exhibits.stanford.edu/silicongenesis/catalog/hr396zc0393. Fun to watch.- youtu.be/HqWWoaA8pIs?t=779 Newton Minow mandated UHF on all television sets in 1961, and the oscillator needed for the tuner was one of the first major non-military products from Fairchild, the 28918 (?).
- youtu.be/HqWWoaA8pIs?t=1053 Fairchild had won the first round of a Minuteman contract, but lost the second one due to poor management
Ahh, you can't have new ideas anymore!
Basically puts together every backend with Front-end web framework to create the exact same website.
The reference live demo can be found at: demo.realworld.io/#/ It is based on Angular.js as it links to: github.com/gothinkster/angularjs-realworld-example-app TODO backend?
There are however also live demos of other frontends, e.g.:Note that all those frontends communicate with the same backend.
- React: react-redux.realworld.io. But note that tag addition at post creation is broken there as of March 2021, but not on master: github.com/gothinkster/react-redux-realworld-example-app/issues/151#issuecomment-808417846 so they forgot to update the live server.
- Vue.js: vue-vuex-realworld.netlify.app
As of 2021 Devs are seemed a bit too focused on monetizing the project through their "how to use this project" premium tutorial, and documentation could be better: just getting the hello world of the most popular backend with the most popular frontend is not easy... come on.
github.com/gothinkster/realworld/issues/578 asks for community support, as devs have moved on since unfortunately.
Remember:
- by default, the frontends hardcode the upstream public data API:
https://conduit.productionready.io/apiso you have to hack their code to match the port of the backend. And each backend can have a different port. - when you switch between backends, you must first manually clear client-side storage cookies/local new run will fail due to authentication issues!
Important missing things from the minimum base app:
- server-side rendering:
- github.com/arrlancore/nextjs-ssr-real-world-app-example. As advertised, that global instance does render with JavaScript disabled! Proposed for upstream at: github.com/gothinkster/realworld/issues/423
- github.com/gothinkster/realworld/issues/266
- no javaScript bi-directional communication library built-in... come on: github.com/gothinkster/realworld/issues/107
- email notifications however as tested on the live demo: demo.realworld.io/#/
- error handling is broken/missing/inconsistent across apps
First you should the most popular backend/frontend combination running, which is the most likely to be working. We managed to run on Ubuntu 20.10, React + Node.js Express.js as described at github.com/gothinkster/node-express-realworld-example-app/pull/116:Then just:on both server and client, and then visit the client URL: localhost:4100/
- github.com/cirosantilli/node-express-realworld-example-app/tree/mongo4 which has a simple patch on top of github.com/gothinkster/node-express-realworld-example-app/tree/ba04b70c31af81ca7935096740a6e083563b3a4a for MongoDB 4 supportThis requires you to first install MongoDB on Ubuntu and ensure you can login to it from the command line.
- github.com/gothinkster/react-redux-realworld-example-app/tree/9186292054dc37567e707602a15a0884d6bdae35 patched to use the correct server host/port
localhost:3000:diff --git a/src/agent.js b/src/agent.js index adfbd72..e3cdc7f 100644 --- a/src/agent.js +++ b/src/agent.js @@ -3,7 +3,7 @@ import _superagent from 'superagent'; const superagent = superagentPromise(_superagent, global.Promise); -const API_ROOT = 'https://conduit.productionready.io/api'; +const API_ROOT = 'http://localhost:3030/api'; const encode = encodeURIComponent; const responseBody = res => res.body;
npm install
npm startYou have to hit the Enter key to add tags, it's terrible: github.com/gothinkster/react-redux-realworld-example-app/issues/151#issuecomment-808417846
One cool thing is that the main repo has unified backend API tests:so the per-repository tests are basically useless, and that single test can test everything for any backend! There is no frontend testing however: github.com/gothinkster/realworld/issues/269 so newb.
git clone https://github.com/gothinkster/realworld
cd realworld
git checkout e7adc6b06b459e578d7d4a6738c1c050598ba431
cd api
APIURL=http://localhost:3000/api USERNAME="u$(date +%s)" ./run-api-tests.sh Unlisted articles are being shown, click here to show only listed articles.