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Illustration of "Number, bases. How to convert decimal, hexadecimal and binary ?"

Bases

A base is a set of symbols (digits) that can be used to represent a value (number).

  • Decimal base = 0 1 2 3 4 5 6 7 8 9
  • Hexadecimal base = 0 1 2 3 4 5 6 7 8 9 A B C D E F (a = 10, b = 11, ...)

The significance of each digit depends on its position (power of N, where N is the number of digits in the base).

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Illustration of "System Architecture: Core, Scheduling, Memory"

 Memory architecture

 Processor architecture

The computer has a processor, which contains cores. Each core contains FPU (Floating Point Unit), ALU (Arithmetic and Logic Unit), registers (very quick memory 1-3 cycles to access), caches (L1, L2, L3 for each core or shared in the whole CPU). The computer also has RAM (80 cycles) and mass-storage memory (milliseconds).

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Illustration of "System security 22 1/2"

ENT test

Find false randomness (not a proof to true randomness)

  • entropy
  • compression
  • chi-square
  • arithmetic mean
  • montecarlo estimation for PI
  • serial correlation coefficient)

https://www.fourmilab.ch/random/

Example: Entropy = 7.980627 bits per character.

Optimum compression would reduce the size
of this 51768 character file by 0 percent.

Chi square distribution for 51768 samples is 1542.26, and randomly
would exceed this value less than 0.01 percent of the times.

Arithmetic mean value of data bytes is 125.93 (127.5 = random).
Monte Carlo value for Pi is 3.169834647 (error 0.90 percent).
Serial correlation coefficient is 0.004249 (totally uncorrelated = 0.0).
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20 posts found