Blade server by Ciro Santilli 37 Updated 2025-07-16
Figure 1. Source. Good image from Wikimedia Commons. In this one we can see how the blades are put vertically, and you get several of them per horizontal rack space, instead of a tipical single rack server going all the way horizontally.
Video 1.
HP Blade Server by Brian Kirsch (2013)
Source.
In the video we can see that it contains RAM, disk storage, we are told about two CPUs, and networking interfaces, so it is a complete computer on its own. He also explains that unlike typical rack servers, each blade unit does not have its own coolers and power supply related hardware, which goes instead on the chassis.
In intuitive terms it consists of all integer functions, possibly with multiple input arguments, that can be written only with a sequence of:
for (i = 0; i < n; i++)
and such that n does not change inside the loop body, i.e. no while loops with arbitrary conditions.
n does not have to be a constant, it may come from previous calculations. But it must not change inside the loop body.
Primitive recursive functions basically include every integer function that comes up in practice. Primitive recursive functions can have huge complexity, and it strictly contains EXPTIME. As such, they mostly only come up in foundation of mathematics contexts.
The cool thing about primitive recursive functions is that the number of iterations is always bound, so we are certain that they terminate and are therefore computable.
This also means that there are necessarily functions which are not primitive recursive, as we know that there must exist uncomputable functions, e.g. the busy beaver function.
Adding unbounded while loops of course enables us to simulate arbitrary Turing machines, and therefore increases the complexity class.
More finely, there are non-primitive total recursive functions, e.g. most famously the Ackermann function.
The algorithm is completely analogous to Diffie-Hellman key exchange in that you efficiently raise a number to a power times and send the result over while keeping as private key.
The only difference is that a different group is used: instead of using the cyclic group, we use the elliptic curve group of an elliptic curve over a finite field.
Video 1.
Elliptic curves by Computerphile (2018)
Source. youtu.be/NF1pwjL9-DE?t=143 shows the continuous group well, but then fails to explain the discrete part.
Inkscape by Ciro Santilli 37 Updated 2025-11-05
Inkscape is a a good software for editing/creating SVG files.
Its functionality is fundamental for as a software for drawing geometry diagrams, as it is a good middle ground between algorithmic generation, and raster graphics.
At 1.0.2, its UI is a bit terrible:
  • the way the menus open on the right with title below the window...
  • several defaults are atrocious, e.g. export drawing rather than page
And it crashes from time to time on Ubuntu 21.04. And it has some glaring bugs, e.g.:
But still, it is a very good initiative.
AI training robot by Ciro Santilli 37 Updated 2025-07-16
It doesn't need to be a bipedal robot. We can let Boston Dynamics worry about that walking balance crap.
It could very well instead be on wheels like arm on tracks.
Or something more like a factory with arms on rails as per:
An arm with a hand and a camera are however indispensable of course!
Figure 1.
Algovivo demo
. github.com/juniorrojas/algovivo: A JavaScript + WebAssembly implementation of an energy-based formulation for soft-bodied virtual creatures.
Borlotti beans by Ciro Santilli 37 Updated 2025-07-16
This looks a lot like the beans that Brazilians venerate and can be easily found in the United Kingdom as of 2020.
The more exact type seems to be pinto bean, but this is close enough.
2021-03: same but 2.5 teaspons, seems to be the right ammount.
2021-02-10: attempt 3: 500g 1 hour 30 minutes no pressure, uncontrolled water. Salt with one chorizo: put 3 teaspoons, it was a bit too much, going to do 2 next time and see.
2020-12-14: attempt 3: 250g of beans, 1.5l of water, 30 minutes pressure.
2020-11-30: attempt 2: 275ml of dry beans, about 50% of 500g bag, putting 1650 ml (6x) of water on pressure cooker Still had to throw out some water.
Density dry raw: 216 g/250 ml = 432 g / 500 ml = 500 g / 580 ml = 864 g/L
500 g dry expands to in water after 12 hours: 1200 ml
Therefore 500 g dry = 864 / 2 L = 432 ml expands about 3x.
Therefore, to the maximum 2.5L of the cooker with 8x dry volume water from this recipe I can use:
2500 = volume expanded bean + volume water = 3 volume dry bean + 8 volume dry bean = 11 volume dry bean
and so:
volume dry bean = 2500/11 = 227ml
which is about 227 / 580 = 40% of the 500 g bag.
After first try, I found that 8x volume of water is way, way too much. Going to try 6x next time.
clang by Ciro Santilli 37 Updated 2025-07-16
LLVM front-end for C and related language like C++ etc.

Pinned article: 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!
We have two killer features:
  1. 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-calculus
    Articles 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/derivative
  2. 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.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . 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.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
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