qflow by Ciro Santilli 37 Updated 2025-07-16
They apparently even produced a real working small RISC-V chip with the flow, not bad.
Asianometry by Ciro Santilli 37 Updated 2025-07-16
Very good channel to learn some basics of semiconductor device fabrication!
Focuses mostly on the semiconductor industry.
youtu.be/aL_kzMlqgt4?t=661 from Video "SMIC, Explained by Asianometry (2021)" from mentions he is of Chinese ascent, ancestors from Ningbo. Earlier in the same video he mentions he worked on some startups. He doesn't appear to speak perfect Mandarin Chinese anymore though based on pronounciation of Chinese names.
asianometry.substack.com/ gives an abbreviated name "Jon Y".
Video 1.
Reflecting on Asianometry in 2022 by Asianometry (2022)
Source. Mentions his insane work schedule: 4 hours research in the morning, then day job, then editing and uploading until midnight. Appears to be based in Taipei. Two videos a week. So even at the current 400k subs, he still can't make a living.
Integrated circuit by Ciro Santilli 37 Updated 2025-08-08
It is quite amazing to read through books such as The Supermen: The Story of Seymour Cray by Charles J. Murray (1997), as it makes you notice that earlier CPUs (all before the 70's) were not made with integrated circuits, but rather smaller pieces glued up on PCBs! E.g. the arithmetic logic unit was actually a discrete component at one point.
The reason for this can also be understood quite clearly by reading books such as Robert Noyce: The Man Behind the Microchip by Leslie Berlin (2006). The first integrated circuits were just too small for this. It was initially unimaginable that a CPU would fit in a single chip! Even just having a very small number of components on a chip was already revolutionary and enough to kick-start the industry. Just imagine how much money any level of integration saved in those early days for production, e.g. as opposed to manually soldering point-to-point constructions. Also the reliability, size an weight gains were amazing. In particular for military and spacial applications originally.
Video 1.
A briefing on semiconductors by Fairchild Semiconductor (1967)
Source.
Shows:
Register transfer level is the abstraction level at which computer chips are mostly designed.
The only two truly relevant RTL languages as of 2020 are: Verilog and VHDL. Everything else compiles to those, because that's all that EDA vendors support.
Much like a C compiler abstracts away the CPU assembly to:
  • increase portability across ISAs
  • do optimizations that programmers can't feasibly do without going crazy
Compilers for RTL languages such as Verilog and VHDL abstract away the details of the specific semiconductor technology used for those exact same reasons.
The compilers essentially compile the RTL languages into a standard cell library.
Examples of companies that work at this level include:
Fabless manufacturing by Ciro Santilli 37 Updated 2025-07-16
In the past, most computer designers would have their own fabs.
But once designs started getting very complicated, it started to make sense to separate concerns between designers and fabs.
What this means is that design companies would primarily write register transfer level, then use electronic design automation tools to get a final manufacturable chip, and then send that to the fab.
It is in this point of time that TSMC came along, and benefied and helped establish this trend.
The term "Fabless" could in theory refer to other areas of industry besides the semiconductor industry, but it is mostly used in that context.
Verilog by Ciro Santilli 37 Updated 2025-07-16
Examples under verilog, more details at Verilator.
SymPy by Ciro Santilli 37 Updated 2025-07-16
This is the dream cheating software every student should know about.
It also has serious applications obviously. www.sympy.org/scipy-2017-codegen-tutorial/ mentions code generation capabilities, which sounds super cool!
The code in this section was tested on sympy==1.8 and Python 3.9.5.
Let's start with some basics. fractions:
from sympy import *
sympify(2)/3 + sympify(1)/2
outputs:
7/6
Note that this is an exact value, it does not get converted to floating-point numbers where precision could be lost!
We can also do everything with symbols:
from sympy import *
x, y = symbols('x y')
expr = x/3 + y/2
print(expr)
outputs:
x/3 + y/2
We can now evaluate that expression object at any time:
expr.subs({x: 1, y: 2})
outputs:
4/3
How about a square root?
x = sqrt(2)
print(x)
outputs:
sqrt(2)
so we understand that the value was kept without simplification. And of course:
sqrt(2)**2
outputs 2. Also:
sqrt(-1)
outputs:
I
I is the imaginary unit. We can use that symbol directly as well, e.g.:
I*I
gives:
-1
Let's do some trigonometry:
cos(pi)
gives:
-1
and:
cos(pi/4)
gives:
sqrt(2)/2
The exponential also works:
exp(I*pi)
gives;
-1
Now for some calculus. To find the derivative of the natural logarithm:
from sympy import *
x = symbols('x')
print(diff(ln(x), x))
outputs:
1/x
Just read that. One over x. Beauty. And now for some integration:
print(integrate(1/x, x))
outputs:
log(x)
OK.
Let's do some more. Let's solve a simple differential equation:
y''(t) - 2y'(t) + y(t) = sin(t)
Doing:
from sympy import *
x = symbols('x')
f, g = symbols('f g', cls=Function)
diffeq = Eq(f(x).diff(x, x) - 2*f(x).diff(x) + f(x), sin(x)**4)
print(dsolve(diffeq, f(x)))
outputs:
Eq(f(x), (C1 + C2*x)*exp(x) + cos(x)/2)
which means:
To be fair though, it can't do anything crazy, it likely just goes over known patterns that it has solvers for, e.g. if we change it to:
diffeq = Eq(f(x).diff(x, x)**2 + f(x), 0)
it just blows up:
NotImplementedError: solve: Cannot solve f(x) + Derivative(f(x), (x, 2))**2
Sad.
Let's try some polynomial equations:
from sympy import *
x, a, b, c = symbols('x a b c d e f')
eq = Eq(a*x**2 + b*x + c, 0)
sol = solveset(eq, x)
print(sol)
which outputs:
FiniteSet(-b/(2*a) - sqrt(-4*a*c + b**2)/(2*a), -b/(2*a) + sqrt(-4*a*c + b**2)/(2*a))
which is a not amazingly nice version of the quadratic formula. Let's evaluate with some specific constants after the fact:
sol.subs({a: 1, b: 2, c: 3})
which outputs
FiniteSet(-1 + sqrt(2)*I, -1 - sqrt(2)*I)
Let's see if it handles the quartic equation:
x, a, b, c, d, e, f = symbols('x a b c d e f')
eq = Eq(e*x**4 + d*x**3 + c*x**2 + b*x + a, 0)
solveset(eq, x)
Something comes out. It takes up the entire terminal. Naughty. And now let's try to mess with it:
x, a, b, c, d, e, f = symbols('x a b c d e f')
eq = Eq(f*x**5 + e*x**4 + d*x**3 + c*x**2 + b*x + a, 0)
solveset(eq, x)
and this time it spits out something more magic:
ConditionSet(x, Eq(a + b*x + c*x**2 + d*x**3 + e*x**4 + f*x**5, 0), Complexes)
Oh well.
Let's try some linear algebra.
m = Matrix([[1, 2], [3, 4]])
Let's invert it:
m**-1
outputs:
Matrix([
[ -2,    1],
[3/2, -1/2]])

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:
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    • 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
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    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
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    Figure 6.
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    .
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