Software

4.1 Types of software and interrupts

Candidates should be able to:

1. Describe the difference between system software and application software and provide examples of each

Note and guidance

• System software provides the services that the computer requires, including operating system and utility software
• Application software provides the services that the user requires

2. Describe the role and basic functions of an operating system

Note and guidance

• Including:
  • managing files
  • handling interrupts
  • providing an interface
  • managing peripherals and drivers
  • managing memory
  • managing multitasking
  • providing a platform for running applications
  • providing system security
  • managing user accounts

3. Understand how hardware, firmware and an operating system are required to run applications software

Note and guidance

• Applications are run on the operating system
• The operating system is run on the firmware
• The bootloader (firmware) is run on the hardware

4. Describe the role and operation of interrupts

Note and guidance

• Including:
  • how an interrupt is generated
  • how it is handled using an interrupt service routine
  • what happens as a result of the interrupts
• Software interrupts include division by zero and two processes trying to access the same memory location
• Hardware interrupts include pressing a key on the keyboard and moving the mouse

4.2 Types of programming language, translators and integrated development environments (IDEs)

Candidates should be able to:

1. Explain what is meant by a high-level language and a low-level language, including the advantages and disadvantages of each

Note and guidance

• Advantages and disadvantages include:
  • ease of reading and writing code, e.g. low-level is hard to read
  • ease of debugging code
  • machine independence
  • direct manipulation of hardware

2. Understand that assembly language is a form of low-level language that uses mnemonics, and that an assembler is needed to translate an assembly language program into machine code

3. Describe the operation of a compiler and an interpreter, including how high-level language is translated by each and how errors are reported

Note and guidance

• A compiler translates the whole code at once before executing it, producing an executable file
• An interpreter translates and executes the code line-by-line
• A compiler provides an error report for the whole code if errors are detected
• An interpreter stops execution when an error is found

4. Explain the advantages and disadvantages of a compiler and an interpreter

Note and guidance

• To include an understanding that an interpreter is mostly used when developing a program and a compiler is used to translate the final program

5. Explain the role of an IDE in writing program code and the common functions IDEs provide

Note and guidance

• Including:
  • code editors
  • run-time environment
  • translators
  • error diagnostics
  • auto-completion
  • auto-correction
  • prettyprint