1.2.2: applications software

• What is the difference between applications and systems software?

  Applications software is utilised directly by the end-user whereas systems software ensures the high performance of the computer. w
• Give 3 examples of utilities

  Compression - Disk defragmentation - Antivirus - Automatic backup - Automatic updating
• Give one advantage of using closed source code

  Thorough, regular and well-tested updates - Expert support and user manuals from company - High levels of security as it is developed in a professional, controlled environment
• State two features of open source code

  • Does not require a license to be used
  • Distributed with the source code
  • Can be modified and sold on
• Give two advantages of using compiled code over interpreted code

  • Faster to execute
  • Does not require compiler to run
• Give two advantages of using interpreted code over compiled code

  • Is platform independent
  • Runs instantly without time waiting for compilation
  • Useful for debugging
• What is assembly language?

  A low-level language that has almost a one-to-one relationship with machine code. It is platform specific.
• What are the stages of compilation?

  • Lexical analysis
  • Syntax analysis
  • Code generation
  • Optimisation
• What happens during syntax analysis?

  • Tokens are compared to the rules of the programming language
  • Syntax errors are identified
  • Symbol table updated with more details
  • Semantic analysis (finding logic errors)
• What are the similarities and differences between static and dynamic linkers?

  Similarities: Both link external modules and libraries to main program Static: Library code copied into the file. File size increased. Dynamic: Addresses of libraries included within file. External updates automatically feed through to main program
• Give three advantages of using libraries

  • Error-free
  • Save time
  • Re-usable
  • No need to ‘reinvent the wheel’
  • Designed by experts
• Describe the function of a loader

  Provided by the operating system, a loader retrieves the library or subroutine from the given memory location.
• What is the purpose of the optimisation stage of compilation?

  • reduce execution time
  • Reduce inefficient sections of code
  • Remove redundant code