Innovative high school Updated +Created
Infineon Technologies Updated +Created
In-order depth-first search Updated +Created
This is the order in which a binary search tree should be traversed for ordered output, i.e.:
  • everything to the left is smaller than parent
  • everything to the right is larger than parent
This ordering makes sense for binary trees and not k-ary trees in general because if there are more than two nodes it is not clear what the top node should go in the middle of.
This is unlike pre-order depth-first search and post-order depth-first search which generalize obviously to general trees.
Indel Updated +Created
Indefinite orthogonal group Updated +Created
Generalization of orthogonal group to preserve different bilinear forms. Important because the Lorentz group is .
Infrastructure as a service Updated +Created
You SSH into a an OS like Ubuntu and do whatever you want from there. E.g. Amazon EC2.
The OS is usually virualized, and you get only a certain share of the CPU by default.
Infrastructure of the University of Oxford Updated +Created
Specified file formats Updated +Created
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.
  • Archive files (.a).
    Libraries meant to be embedded into executables during the Linking step.
  • 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.
PAE and PSE page table schemes Updated +Created
If either PAE and PSE are active, different paging level schemes are used:
  • no PAE and no PSE: 10 | 10 | 12
  • no PAE and PSE: 10 | 22.
    22 is the offset within the 4Mb page, since 22 bits address 4Mb.
  • PAE and no PSE: 2 | 9 | 9 | 12
    The design reason why 9 is used twice instead of 10 is that now entries cannot fit anymore into 32 bits, which were all filled up by 20 address bits and 12 meaningful or reserved flag bits.
    The reason is that 20 bits are not enough anymore to represent the address of page tables: 24 bits are now needed because of the 4 extra wires added to the processor.
    Therefore, the designers decided to increase entry size to 64 bits, and to make them fit into a single page table it is necessary reduce the number of entries to 2^9 instead of 2^10.
    The starting 2 is a new Page level called Page Directory Pointer Table (PDPT), since it _points_ to page directories and fill in the 32 bit linear address. PDPTs are also 64 bits wide.
    cr3 now points to PDPTs which must be on the fist four 4GB of memory and aligned on 32 bit multiples for addressing efficiency. This means that now cr3 has 27 significative bits instead of 20: 2^5 for the 32 multiples * 2^27 to complete the 2^32 of the first 4GB.
  • PAE and PSE: 2 | 9 | 21
    Designers decided to keep a 9 bit wide field to make it fit into a single page.
    This leaves 23 bits. Leaving 2 for the PDPT to keep things uniform with the PAE case without PSE leaves 21 for offset, meaning that pages are 2M wide instead of 4M.
Intelligence Updated +Created
Instruction set architecture Updated +Created
The main interface between the central processing unit and software.
Integer factorization algorithm Updated +Created
csvgrep from csvkit Updated +Created
Install MongoDB on Ubuntu Updated +Created
Tested as of Ubuntu 20.04, there is no Mongo package available by default due to their change to Server Side Public License, which Debian opposed. Therefore, you have to add their custom PPA as mentioned at: docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/
Install Conda on Ubuntu Updated +Created
Tested on Ubuntu 20.04:
mkdir -p ~/miniconda3
wget https://repo.anaconda.com/miniconda/Miniconda3-py311_23.11.0-2-Linux-x86_64.sh -O ~/miniconda3/miniconda.sh
bash ~/miniconda3/miniconda.sh -b -u -p ~/miniconda3
rm -rf ~/miniconda3/miniconda.sh
~/miniconda3/bin/conda init bash
. ~/.bashrc
and from then on we can do conda commands normally.
At that time, the exact installer under latest appears to have been: repo.anaconda.com/miniconda/Miniconda3-py311_23.11.0-2-Linux-x86_64.sh
The best Caetano Veloso songs Updated +Created
.strtab Updated +Created
Holds strings for the symbol table.
This section has sh_type == SHT_STRTAB.
It is pointed to by sh_link == 5 of the .symtab section.
readelf -x .strtab hello_world.o
outputs:
Hex dump of section '.strtab':
  0x00000000 0068656c 6c6f5f77 6f726c64 2e61736d .hello_world.asm
  0x00000010 0068656c 6c6f5f77 6f726c64 0068656c .hello_world.hel
  0x00000020 6c6f5f77 6f726c64 5f6c656e 005f7374 lo_world_len._st
  0x00000030 61727400                            art.
This implies that it is an ELF level limitation that global variables cannot contain NUL characters.
Intel Arc Updated +Created
Video 1.
Worst We've Tested: Broken Intel Arc GPU Drivers by Gamers Nexus (2022)
Source.
AlphaZero Updated +Created
www.quora.com/Which-chess-engine-would-be-stronger-Alpha-Zero-or-Stockfish-12/answer/Felix-Zaslavskiy explains that it beat Stockfish 8. But then Stockfish was developed further and would start to beat it. We know this because although AlphaZero was closed source, they released the trained artificial neural network, so it was possible to replay AlphaZero at its particular stage of training.

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