Operating Systems and Software
Operating Systems and Software
This domain examines what an operating system does, how software is classified, and how users and programs interact with hardware. Questions often ask you to distinguish system software from application software and to match operating-system types to situations.
Core rules
- An operating system manages processes, memory, files, devices and security, and provides a user interface. It is system software, not an application.
- Functions include process scheduling, memory allocation, file management, device management through drivers, and access control.
- Types include batch, multiprogramming, multitasking, time-sharing, real-time, distributed and mobile. Time-sharing supports interactive multi-user work; real-time systems must meet deadlines.
- Software categories: system software (operating system, language translators, utilities), application software (word processor, spreadsheet), and firmware stored in ROM.
- Open-source software allows access to source code and modification under its licence; proprietary software does not.
Worked example
A school wants a free, multi-user laboratory operating system that can run a browser and office suite, with separate student accounts and shared printers. Linux is suitable: it is open-source, supports multi-user accounts and permissions, manages shared printers, and runs productivity applications. A single-user real-time operating system would be a poor choice because the laboratory needs interactive general-purpose use, not deadline-driven control of machinery.
Traps
- Calling an operating system application software loses marks; it is system software.
- A graphical user interface is an interface, not proof that an operating system is present.
- Multiprogramming keeps several programs in memory; multitasking gives the appearance of simultaneous execution on one CPU. Do not swap the definitions.
- Utility programs such as antivirus and backup tools are not the operating system itself.
- Freeware is not the same as open source; freeware may withhold source code.
- A language translator converts source code; it does not manage hardware directly.