COMPUTER SCIENCE WEEK 2

    Cards (7)

    • Control Unit - decodes instructions. Co-ordinates the execution of instructions. Directs the fetch, decode, execute cycle.
      Clock - Sends a regular electrical pulse which synchronises the components. Influences the number of instructions carried out each second
      Cache - Makes retrieving data from the computer's memory more efficient. Stores data for faster access, and also stores frequently used data.
    • To increase a computer's performance
      • Increase the clock speed
      • Increase the number of processor core
      • Increase the cache size
    • HLL VS LLL
      • HLL has higher level of abstraction
      • HLL runs across different CPU families.
      • HLL uses English-like language so it is easier to understand and learn
      • Programs written in LLL are usually more efficient
      • Programs written in LLL usually use less memory
      • Programs written in LLL can directly access hardware components.
    • Compiler vs Interpreter
      • Translates the whole program in one go(C)
      • Standalone program does not require the compiler on computer to run(C)
      • Produces a list of errors after translation(C)
      • Translates code one line at a time(I)
      • Program requires interpreter to be present to run the code(I)
      • Stops execution as soon as an error is encountered(I)
    • Computer Network
      A group of computers that are linked together
    • Encryption
      Encryption scrambles the data before transmission and changes plaintext into ciphertext so it cannot be read by unauthorised users.
    • EMBEDDED SYSTEMS VS NON-EMBEDDED
      • An embedded system is a computer system with a dedicated function, inside a larger mechanical unit, e.g. traffic lights, washing machines, dishwashers and coffee machines.
      • A non-embedded system is a computer system with multiple functions, referred to a general-purpose machine
      • An embedded system compared to a non-embedded system is typically:
      • smaller in size
      • lower power
      • lower cost
      • lower processing power 
      • lower memory
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