Tinker Tailor Soldier Spy (film) Updated 2025-07-16
This is not bad, but some divergences to the better BBC miniseries, which presumably sticks more closely to the novel:
  • in the film Jim Prideaux is captured in a cafe in Prague, in the series it's in the woods. It is therefore much more plausible that he would have been shot.
  • in the film Peter Guillam is played by Benedict Cumberbatch, who feels a bit young to be Ricki Tarr's boss. Not impossible, but still.
  • the series is much less chronological, and more flashback based, as new information becomes available. The film is more chronological, which makes it easier to understand, but less interesting at the same time.
  • in the film they shoot the Russian girl Irina in front of Jim, in the series the fact that she was shot is only known through other sources. The film has more eye candy, which weakens it.
  • Toby Esterhase is not threatened in an airfield, only in a safe ;house in London.
How large primes are found for RSA Updated 2025-07-16
Answers suggest hat you basically pick a random large odd number, and add 2 to it until your selected primality test passes.
The prime number theorem tells us that the probability that a number between 1 and is a prime number is .
Therefore, for an N-bit integer, we only have to run the test N times on average to find a prime.
Since say, A 512-bit integer is already humongous and sufficiently large, we would only need to search 512 times on average even for such sizes, and therefore the procedure scales well.
Human Compatible Updated 2025-07-16
The key takeaway is that setting an explicit value function to an AGI entity is a good way to destroy the world due to poor AI alignment. We are more likely to not destroy by creating an AI whose goals is to "do want humans what it to do", but in a way that it does not know before hand what it is that humans want, and it has to learn from them. This approach appears to be known as reward modeling.
Some other cool ideas:
  • a big thing that is missing for AGI in the 2010's is some kind of more hierarchical representation of the continuous input data of the world, e.g.:
  • game theory can be seen as part of artificial intelligence that deals with scenarios where multiple intelligent agents are involved
  • probability plays a crucial role in our everyday living, even though we don't think too much about it every explicitly. He gives a very good example of the cost/risk tradeoffs of planning to the airport to catch a plane. E.g.:
    • should you leave 2 days in advance to be sure you'll get there?
    • should you pay an armed escort to make sure you are not attacked in the way?
  • economy, and notably the study of the utility, is intrinsically linked to AI alignment
so the solution is:
We notice that the solution has continuous spectrum, since any value of can provide a solution.
Heat equation Updated 2025-07-16
Besides being useful in engineering, it was very important historically from a "development of mathematics point of view", e.g. it was the initial motivation for the Fourier series.
Some interesting properties:
Array of Elf64_Shdr structs.
Each entry contains metadata about a given section.
e_shoff of the ELF header gives the starting position, 0x40 here.
e_shentsize and e_shnum from the ELF header say that we have 7 entries, each 0x40 bytes long.
So the table takes bytes from 0x40 to 0x40 + 7 + 0x40 - 1 = 0x1FF.
Some section names are reserved for certain section types: www.sco.com/developers/gabi/2003-12-17/ch4.sheader.html#special_sections e.g. .text requires a SHT_PROGBITS type and SHF_ALLOC + SHF_EXECINSTR
Running:
readelf -S hello_world.o
outputs:
There are 7 section headers, starting at offset 0x40:

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .data             PROGBITS         0000000000000000  00000200
       000000000000000d  0000000000000000  WA       0     0     4
  [ 2] .text             PROGBITS         0000000000000000  00000210
       0000000000000027  0000000000000000  AX       0     0     16
  [ 3] .shstrtab         STRTAB           0000000000000000  00000240
       0000000000000032  0000000000000000           0     0     1
  [ 4] .symtab           SYMTAB           0000000000000000  00000280
       00000000000000a8  0000000000000018           5     6     4
  [ 5] .strtab           STRTAB           0000000000000000  00000330
       0000000000000034  0000000000000000           0     0     1
  [ 6] .rela.text        RELA             0000000000000000  00000370
       0000000000000018  0000000000000018           4     2     4
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), l (large)
  I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
  O (extra OS processing required) o (OS specific), p (processor specific)
The struct represented by each entry is:
typedef struct {
    Elf64_Word  sh_name;
    Elf64_Word  sh_type;
    Elf64_Xword sh_flags;
    Elf64_Addr  sh_addr;
    Elf64_Off   sh_offset;
    Elf64_Xword sh_size;
    Elf64_Word  sh_link;
    Elf64_Word  sh_info;
    Elf64_Xword sh_addralign;
    Elf64_Xword sh_entsize;
} Elf64_Shdr;
Quartz clock Updated 2025-07-16
Video 1.
How a quartz watch works by Steve Mould (2017)
Source. Mentions feedback loop loop with the quartz tuning fork for the piezoelectricity and an amplifier. Also mentions the choice of 32768 Hertz () as the first power of 2 that is outside of the human hearing range, and then how a frequency divider is used to reduce the frequency to get the second counter.
Animal-in-the-loop Updated 2025-07-16
Ciro Santilli invented this term, it refers to mechanisms in which you put an animal in a virtual world that the animal can control, and where you can measure the animal's outputs.
Here's to the crazy ones Updated 2025-07-16
Because the people who are crazy enough to think they can change the world are the ones who do.
We will get into more detail later, but it is good to have it in mind now:
  • section: exists before linking, in object files.
    One ore more sections will be put inside a single segment by the linker.
    Major information sections contain for the linker: is this section:
    • raw data to be loaded into memory, e.g. .data, .text, etc.
    • or metadata about other sections, that will be used by the linker, but disappear at runtime e.g. .symtab, .srttab, .rela.text
  • 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.
III-V semiconductor Updated 2025-07-16
Most notable example: gallium arsenide, see also: gallium arsenide vs silicon.
An important class of semiconductors, e.g. there is a dedicated III-V lab at: École Polytechnique: www.3-5lab.fr/contactus.php
The ELF standard specifies multiple file formats:
  • Object files (.o).
    Intermediate step to generating executables and other formats:
    Source code
    
        |
        | Compilation
        |
        v
    
    Object file
    
        |
        | Linking
        |
        v
    
    Executable
    Object files exist to make compilation faster: with make, we only have to recompile the modified source files based on timestamps.
    We have to do the linking step every time, but it is much less expensive.
  • Executable files (no standard Linux extension).
    This is what the Linux kernel can actually run.
  • Shared object files (.so).
    Libraries meant to be loaded when the executable starts running.
  • Core dumps.
    Such files may be generated by the Linux kernel when the program does naughty things, e.g. segfault.
    They exist to help debugging the program.
In this tutorial, we consider only object and executable files.

There are unlisted articles, also show them or only show them.