Definition and purpose of operating systems

Summary

An operating system (OS) is system software that manages a computer’s hardware and software resources and provides common services for computer programs. It acts as an intermediary between applications and the underlying hardware for functions like input/output and memory allocation, while application code typically runs directly on the hardware and interacts with the OS through system calls or interrupts. Operating systems are used across many devices, from phones and consoles to servers and supercomputers. The purpose of an OS is commonly described through three main goals: (1) allocating resources so multiple applications can share limited CPU time and memory without one monopolizing the system; (2) isolating applications from each other to improve reliability and security while still allowing communication; and (3) providing an interface that abstracts hardware details to simplify programming and enable portability. Operating systems also supply common services (such as access to network and disk devices) and use virtualization features like virtual memory to mask limited hardware resources and present a more convenient computing environment.

Key Points

• 1

  An OS manages hardware/software resources and provides shared services to applications.

• 2

  Its core purposes include resource allocation, application isolation (reliability/security), and hardware abstraction via a programming interface.

• 3

  Operating systems enable common device/network services and may use virtualization (e.g., virtual memory) to improve usability and portability.