Ciro Santilli @cirosantilli  40

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Non-ionizing radiation Updated 2025-07-16

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Upsert Updated 2025-07-16

UPSERT is extremely handy, and reduces the number of find, check on server, update loops. But RETURNING is a fundamental part of that (to get the updated/existing) ID. Can't believe SQL hasn't standardized it yet as of 2022. But both SQLite and Postgres support it with similar syntax thankfully.

nodejs/sequelize/raw/upsert.js

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IBM quantum computer Updated 2025-07-16

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MSc course of the University of Oxford Updated 2025-07-16

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Daniel Sank Updated 2025-07-16

Cool dude. Uses Stack Exchange: physics.stackexchange.com/users/31790/danielsank

Started at Google Quantum AI in 2014.

Has his LaTeX notes at: github.com/DanielSank/theory. One day he will convert to OurBigBook.com. Interesting to see that he is able to continue his notes despite being at Google.

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Sycamore processor Updated 2025-07-16

This is a good read: quantumai.google/hardware/datasheet/weber.pdf May 14, 2021. Their topology is so weird, not just a rectangle, one wonders why! You get different error rates in different qubits, it's mad.

Figure 1.
Google Sycamore Weber quantum computer connectivity graph
. Weber is a specific processor of the Sycamore family. From this we see it clearly that qubits are connected to at most 4 other qubits, and that the full topology is not just a simple rectangle.

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Who are the developers that are making the most money through GitHub sponsors? Updated 2025-07-16

github.com/isaacs/github/issues/1824

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Inside Job (2010) Updated 2025-07-16

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Margin Call (2011) Updated 2025-07-16

Peter Sullivan discovers the issue scene from Margin Call

Senior partners emergency meeting scene from Margin Call

. Source. God, Jeremy Irons is destroying it!!! And all others too.

Fire Sale of Mortgage Bonds scene from Margin Call

Investment Analyst Explains Margin Call by The Plain Bagel

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The Big Short (2015) Updated 2025-07-16

I'm Jacked to the Tits remix by The Big Short (2021)

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FeatherJS demo apps Updated 2025-07-16

github.com/feathersjs/awesome-feathersjs#projects-using-feathers

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FeathersJS Heroku deployment Updated 2025-07-16

Got it working as mentioned at: github.com/cirosantilli/feathers-chat/tree/sequelize-pg

One major step was to port to PostgreSQL as shown at feathers-chat PostgreSQL.

Bibliography:

There's also a heroku branch at: github.com/feathersjs/feathers-chat/tree/heroku, but it also seems to use NeDB? So you can have a filesystem in Heroku? Doesn't seem so: stackoverflow.com/questions/42775418/heroku-local-persistent-storage

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FeathersJS signup email verification Updated 2025-07-16

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Faster-than-light implies time travel Updated 2025-07-16

Figure 1.
Spacetime diagram illustrating how faster-than-light travel implies time travel
. Legend an explanation are shown in this answer.

Bibliography:

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Tachyon Updated 2025-07-16

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Tachyonic antitelephone Updated 2025-07-16

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Realworld app written in Express Updated 2025-07-16

gothinkster/realworld implementations based on Express.js.

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ELF Hello World Tutorial / STT_FILE Updated 2025-07-16

Entry 1 has ELF64_R_TYPE == STT_FILE. ELF64_R_TYPE is continued inside of st_info.

10 8: st_name = 01000000 = character 1 in the .strtab, which until the following \0 makes hello_world.asm
This piece of information file may be used by the linker to decide on which segment sections go: e.g. in ld linker script we write:
```
segment_name :
{
    file(section)
}
```
to pick a section from a given file.
Most of the time however, we will just dump all sections with a given name together with:
```
segment_name :
{
    *(section)
}
```
10 12: st_info = 04
Bits 0-3 = ELF64_R_TYPE = Type = 4 = STT_FILE: the main purpose of this entry is to use st_name to indicate the name of the file which generated this object file.
Bits 4-7 = ELF64_ST_BIND = Binding = 0 = STB_LOCAL. Required value for STT_FILE.
10 13: st_shndx = Symbol Table Section header Index = f1ff = SHN_ABS. Required for STT_FILE.
20 0: st_value = 8x 00: required for value for STT_FILE
20 8: st_size = 8x 00: no allocated size

Now from the readelf, we interpret the others quickly.

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ELF Hello World Tutorial / STT_SECTION Updated 2025-07-16

There are two such entries, one pointing to .data and the other to .text (section indexes 1 and 2).

Num:    Value          Size Type    Bind   Vis      Ndx Name
  2: 0000000000000000     0 SECTION LOCAL  DEFAULT    1
  3: 0000000000000000     0 SECTION LOCAL  DEFAULT    2

TODO what is their purpose?

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ELF Hello World Tutorial / STT_NOTYPE Updated 2025-07-16

Then come the most important symbols:

Num:    Value          Size Type    Bind   Vis      Ndx Name
  4: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT    1 hello_world
  5: 000000000000000d     0 NOTYPE  LOCAL  DEFAULT  ABS hello_world_len
  6: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT    2 _start

hello_world string is in the .data section (index 1). It's value is 0: it points to the first byte of that section.

_start is marked with GLOBAL visibility since we wrote:

global _start

in NASM. This is necessary since it must be seen as the entry point. Unlike in C, by default NASM labels are local.

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