Operating System (OS)
Definition
An operating system is a collection of software that manages computer hardware and provides services for computer programs. It acts as an interface between the user and the computer hardware, enabling the user to perform various tasks such as managing files, running applications, and communicating with peripheral devices.
Key Point
Key Functions of an Operating System:
• Memory Management - Allocates memory to programs and manages paging, segmentation, and virtual memory
• Resource Management - Manages CPU time and the execution of processes
• File Management - Handles storage, retrieval, and organisation of files
• Input/Output Management - Manages communication with peripheral devices through device drivers
• Interrupt Management - Handles interrupts to ensure efficient processing
• User Interface - Provides graphical (GUI) or command-line (CLI) interfaces
• Memory Management - Allocates memory to programs and manages paging, segmentation, and virtual memory
• Resource Management - Manages CPU time and the execution of processes
• File Management - Handles storage, retrieval, and organisation of files
• Input/Output Management - Manages communication with peripheral devices through device drivers
• Interrupt Management - Handles interrupts to ensure efficient processing
• User Interface - Provides graphical (GUI) or command-line (CLI) interfaces
Why an Operating System Is Needed
Without an operating system, every program would need its own code to control the processor, memory, storage and each peripheral. The operating system does this once for all of them: it hides the complexity of the hardware and gives applications a platform to run on.
Key Point
Further roles of an operating system:
• Security and user management - Controls who can log in, manages user accounts and sets access rights to files and other resources
• Providing a platform for software - Applications ask the operating system for services, such as opening a file, instead of controlling the hardware themselves
• Providing utilities - Supplies programs used to monitor, manage and maintain the computer
• Security and user management - Controls who can log in, manages user accounts and sets access rights to files and other resources
• Providing a platform for software - Applications ask the operating system for services, such as opening a file, instead of controlling the hardware themselves
• Providing utilities - Supplies programs used to monitor, manage and maintain the computer
Exam Tip
When a question asks you to describe a role of an operating system, name the role and then say what the operating system does. For example: memory management, where it allocates RAM to programs and moves data to virtual memory when RAM is full.