Understanding Operating Systems (OS)
An operating system (OS) is a software program that manages a computer’s resources and facilitates communication between applications and hardware.
While some programs may directly communicate with hardware, most software is designed to interact with the operating system instead.
Evolution of Operating Systems
In the early days of computers, operating systems were not available.
Each program had to include all the necessary code to run, connect with hardware, and perform its intended function.
This approach made software development complex and restricted programs to specific computers.
Operating systems serve various functions to achieve specific objectives:
- Process Management: The CPU may have multiple processes in the ready state at any given time. The operating system ensures fair access to resources and manages process execution using scheduling techniques like first come, first served, round-robin, shortest job first, and priority scheduling.
- Memory Management: The operating system is responsible for loading processes into the main memory for execution and releasing memory when processes are completed, allowing it to be used by other processes.
- I/O Device Management: Various I/O devices exist within a system, and different processes require access. The operating system handles the authorization and allocation of I/O devices to necessary processes.
- File Management: Operating systems maintain and handle files, folders, and directory structures on computers. A File Allocation Table (FAT) stores information about each file, such as filename, size, and type. Additionally, the operating system ensures file security by preventing unauthorized access.
- Virtual Memory: When the size of an application exceeds the main memory capacity, the operating system loads frequently used pages into memory, a technique known as virtual memory.
Popular Operating Systems
Throughout computing history, several operating systems have gained popularity:
- Microsoft Windows: Windows is the widely used operating system for PCs and IBM-compatible systems. Windows 10 is the most recent version.
- macOS: macOS is Apple’s core operating system for desktop and laptop computers.
- Linux: Linux is a free and open-source operating system that can be installed on PCs and IBM-compatible systems. It has various distributions such as Ubuntu, Debian, Red Hat, and Slackware.
- Chrome OS/Chromium: Chrome OS comes pre-installed on Google Chromebooks.
Operating Systems for Mobile Devices:
Mobile operating systems designed for smartphones and tablets have gained significant prominence
- Android: Android is the most common mobile operating system worldwide, running on a wide range of smartphones.
- iOS: iOS is Apple’s operating system exclusively used on iPhones and iPads.