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Computer Science GCES AQA

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  1. Representing Algorithms Aqa
    4 主题
  2. Efficiency Of Algorithms Aqa
    1 主题
  3. Searching Algorithms Aqa
    3 主题
  4. Sorting Algorithms Aqa
    3 主题
  5. Data Types Aqa
    1 主题
  6. Programming Concepts Aqa
    5 主题
  7. Arithmetic Relational And Boolean Operations Aqa
    1 主题
  8. Data Structures Aqa
    3 主题
  9. String Manipulation Aqa
    1 主题
  10. Random Number Generation Aqa
    1 主题
  11. Structured Programming Aqa
    2 主题
  12. Robust And Secure Programming Aqa
    4 主题
  13. Number Bases Aqa
    2 主题
  14. Converting Between Number Bases Aqa
    3 主题
  15. Units Of Information Aqa
    9 主题
  16. Hardware And Software Aqa
    4 主题
  17. Boolean Logic Aqa
    3 主题
  18. Programming Languages And Translators Aqa
    2 主题
  19. Cpu Architecture Performance And Embedded Systems Aqa
    4 主题
  20. Memory Aqa
    2 主题
  21. Secondary Storage Aqa
    3 主题
  22. Fundamentals Of Computer Networks Aqa
    8 主题
  23. Fundamentals Of Cyber Security Aqa
    1 主题
  24. Methods Of Preventing Cyber Security Threats Aqa
    1 主题
  25. Relational Databases Aqa
    2 主题
  26. Ethical Legal And Environmental Impacts Aqa
    2 主题
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Exam code:8525

  • Since the invention of the computer, people have needed to learn how to communicate with them using programming languages

  • Early computers were complex and instructions would have to be in written in binary code, 0s and 1s

  • This process was slow, taking days to program simple tasks

  • Over time, new generations of programming languages have enabled people to become faster and more efficient at writing programs as they resemble human language

  • Generations of programming languages can be split in to two categories:

    • Low-level

      • First generation

      • Second generation

    • High-level

      • Third generation

Low-Level Languages

What is a low-level language?

  • A low-level language is a programming language that directly translates to machine code understood by the processor

  • Low-level languages allow direct control over hardware components such as memory and registers

  • These languages are written for specific processors to ensure they embed the correct machine architecture

First generation

  • Machine code is a first-generation language

  • Instructions are directly executable by the processor

  • Written in binary code

Second generation

  • Assembly code is a second-generation language

  • The code is written using mnemonics, abbreviated text commands such as LDA (Load), STA(Store) 

  • Using this language programmers can write human-readable programs that correspond almost exactly to machine code

  • One assembly language instruction translates to one machine code instruction

  • Needs to be translated into machine code for the computer to be able to execute it

Advantages

Disadvantages

Complete control over the system components

Difficult to write and understand

Occupy less memory and execute faster

Machine dependent

Direct manipulation of hardware

More prone to errors

 

Knowledge of computer architecture is key to program effectively

High-Level Languages

What is a high-level programming language?

  • A high-level programming language uses English-like statements to allow users to program with easy to use code

  • Most computer programs are now written in high-level languages

  • High-level languages allow for clear debugging and once programs are created they are easier to maintain

  • High level languages were needed due to the development of processor speeds and the increase in memory capacity

  • One instruction translates into many machine code instructions

  • Needs to be translated into machine code for the computer to be able to execute it

  • Examples of high-level languages include:

    • Python

    • Java

    • Basic

    • C+

Advantages

Disadvantages

Easier to read and write

The user is not able to directly manipulate the hardware

Easier to debug

Needs to be translated to machine code before running

Portable so can be used on any computer

The program may be less efficient

One line of code can perform multiple commands

 

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