The Operating System

Introduction to Operating Systems

Operating systems (OS): These are essential system software that control the overall operation of a computer system.
Allow interaction between users and hardware. Without an OS, users would need to communicate with the computer hardware directly through machine code.
Directly manages hardware, system resources, and provides services for other software to function.
The OS acts as an interface between the user and the computer hardware.

Core Functions of Operating Systems

Process Management: The OS decides when and how processes (i.e., executable programs) are run. It schedules system resources to ensure the efficient execution of processes.
Memory Management: The OS allocates and tracks memory space for each application and for the system itself. This includes loading programs into memory for execution and freeing memory when programs terminate.
File Management: The OS oversees the organisation, storage, retrieval, and sharing of data files. It also controls access and security of files.
Device Management: The OS handles input and output to and from hardware devices. This includes managing drivers, which are computer programs that control a device.
User Interface (UI): Either command line (where users type commands) or Graphical User Interface (GUI), where users interact with visual elements like icons and windows. The OS defines how users interact with the system.

Types of Operating Systems

Batch OS: Executes batches (groups) of jobs without user interaction. Users submit jobs, which the OS groups together to execute at once.
Multiprogramming OS: Allows multiple programs to reside in the system memory at the same time. The OS switches execution between programs, increasing system utilisation.
Multitasking OS: Similar to multiprogramming, but the OS can manage multiple tasks of a single program concurrently.
Real-Time OS: Used in systems that require immediate real-time response, such as scientific instruments or control systems.

Examples of Operating Systems

Windows: Developed by Microsoft, known for its GUI, Windows is the most commonly used OS for personal computers.
Mac OS: Developed by Apple for their personal computers, Mac OS is known for its streamlined design and user-friendly interfaces.
Linux: An open-source OS often used for servers and in business environments. Highly customisable with a variety of distributions (e.g., Ubuntu, Fedora).
iOS and Android: Used primarily on mobile devices like smartphones and tablets.