This is the lowest level of abstraction computer, at which the basic gates and power are described.
At this level, you are basically thinking about the 3D layered structure of a chip, and how to make machines that will allow you to create better, usually smaller, gates.
FFFFF 000 points to its own physical address FFFFF 000. This kind of translation is called an "identity mapping", and can be very convenient for OS-level debugging.
Intel is known to have created customized chips for very large clients.
This is mentioned e.g. at: www.theregister.com/2021/03/23/google_to_build_server_socs/
Intel is known to do custom-ish cuts of Xeons for big customers.
Those chips are then used only in large scale server deployments of those very large clients. Google is one of them most likely, given their penchant for Google custom hardware.
TODO better sources.
Info-ZIP by Ciro Santilli 40 Updated 2025-07-16
The dominant Linux implemenation, e.g. default zip command on Ubuntu 23.04.
So dominant that it is usualy called just "zip".
y86.js.org by Ciro Santilli 40 Updated 2025-07-16
The good:
  • slick UI! But very hard to read characters, they're way too small.
  • attempts to show state diffs with a flash. But it goes by too fast, would be better if it were more permanent
  • Reverse debugging
The bad:
Flash memory by Ciro Santilli 40 Updated 2025-07-16
Video 1.
The Engineering Puzzle of Storing Trillions of Bits in your Smartphone / SSD using Quantum Mechanics by Branch Education (2020)
Source. Nice animations show how quantum tunnelling is used to set bits in flash memory.
Hyperscale computing by Ciro Santilli 40 Updated 2025-07-16
Basically means "company with huge server farms, and which usually rents them out like Amazon AWS or Google Cloud Platform
Figure 1.
Global electricity use by data center type: 2010 vs 2018
. Source. The growth of hyperscaler cloud vs smaller cloud and private deployments was incredible in that period!
Platform as a service by Ciro Santilli 40 Updated 2025-07-16
Highly managed, you don't even see the Docker images, only some higher level JSON configuration file.
These setups are really convenient and cheap, and form a decent way to try out a new website with simple requirements.
By default, LSF only sends you an email with the stdout and stderr included in it, and does not show or store anything locally.
One option to store things locally is to use:
bsub -oo stdout.log -eo stderr.log 'echo myout; echo myerr 1>&2'
as documented at:Or to use files with the job id in them:
bsub -oo %J.out -eo %J.err 'echo myout; echo myerr 1>&2'
By default bsub -oo:
  • also contains the LSF metadata in addition to the actual submitted process stdout
  • prevents the completion email from being sent
To get just the stdout to the file, use bsub -N -oo which:
  • stores only stdout on the file
  • re-enables the completion email
as mentioned at:
Another option is to run with the bsub -I option:
bsub -I 'echo a;sleep 1;echo b;sleep 1;echo c'
This immediately prints stdout and stderr to the terminal.
Raspberry Pi Pico H by Ciro Santilli 40 Updated 2025-07-26
Has Serial wire debug debug pre-soldered. Why would you ever get one without unless you are a clueless newbie like Ciro Santilli?!?!
It is however possible to solder it yourself on Raspberry Pi Pico W.
Jerry Sanders by Ciro Santilli 40 Updated 2025-07-16
Video 1.
AMD Founder Jerry Sanders Interview (2002)
Source. Source: exhibits.stanford.edu/silicongenesis/catalog/hr396zc0393. Fun to watch.
3SUM by Ciro Santilli 40 Updated 2025-07-16
It is cool how even for such a "simple looking" problem, we were still unable to prove optimality as of 2020!
Leanpub by Ciro Santilli 40 Updated 2025-07-16
Founder: Peter Armstrong
The general idea is publishing entire books with usual copyright, but with gradual updates.
ruboss.com/ documents their stack, a somewhat similar choice to OurBigBook.com as of 2021, notably Next.js. But backend in Ruby on Rails. They actually managed Apollo/GraphQL, which Ciro Santilli would have liked, but din't have the patience for.
The founder/CEO Peter Armstrong www.linkedin.com/in/peterburtonarmstrong/ He looks like a nice guy.

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