Software and Operating Systems
Domain focus
This section tests the difference between system and application software, the functions of an operating system, user interfaces and translators.
Core rules
- System software manages the computer; application software performs a user task.
- An operating system (OS) manages processes, memory, files, devices and security, and provides a user interface. Examples: Windows, Linux, macOS, Android.
- Interfaces: command-line (CLI) uses typed commands; graphical (GUI) uses windows, icons, menus and pointers.
- Multitasking runs several tasks apparently at once; multiprocessing uses more than one CPU/core.
- Utility programs maintain the system: antivirus, backup, disk cleanup, compression.
- Translators: a compiler translates the whole source program into object code before running; an interpreter translates and executes line by line; an assembler translates assembly language into machine code.
- Open-source software allows source-code access and modification; proprietary software is licensed and closed.
Worked example
A school has old PCs with 1 GB RAM and no software budget. Recommend an operating-system type and justify it. Reasoning: a lightweight Linux distribution is suitable because it is open source (no licence fee), can run on low RAM and supports a GUI or CLI. The justification must mention cost and hardware fit, not just “Linux is good”.
Traps
- Calling a word processor system software.
- Saying an interpreter produces a permanent object file; that is a compiler.
- Treating a utility such as antivirus as the operating system.
- Confusing GUI with “Google”.
- Claiming open source always means free of charge; it refers to source-code freedom.