# 2019-2020-1 20,175,333 Caoya Kun "Information security system design basis" the second week of learning summary

2019-2020-1 20,175,333 Caoya Kun "Information security system design basis" the second week of learning summary

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Learning content summary

• Hexadecimal conversion

• Common decimal: decimal, binary, octal and hexadecimal
  every few into a few decimal
  true value is equal to the number multiplied by the weights bit
• Binary conversion
  using the short division, the number obtained reverse order is also desired
  decimal to hexadecimal other, except a few hexadecimal is converted into several, in reverse order
  (decimal multiplication replaced by other)

• The concept of position

• Bit-level operations
• logic operation
• Shift operation (shift right arithmetic signed values ​​[] and [unsigned shift right logical])

• Information is context-bit +

• Have signed
• Unsigned
  computer is often used to complement or unsigned expressed, the same binary number might be represented by different numbers
• Float
  IEEE floating-point number represents: the symbol s = 1 s = 0 when a negative number is positive
  exponent E represents the weight of
  an offset constant Bias

• Numerical computation

• Unsigned
• There are several (complement) Symbol

• Store information

• Large and small end segment: treatment of the same data for different data types with different processing methods
• Network byte order: a network data stream is a stream of bytes, the first byte is considered high, big endian.
  When the transmission can not be converted.

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