What is Operating System (OS)?

Operating System (OS) is a software program that manages the resources of a computer and allows communication between programs and computer hardware.

In the past, there were no operating systems. Thus, every computer program had to include all of the code needed to run the program, connect it to the hardware, and show the actual function of the program. Therefore, computer programs were difficult to create and too complicated to operate. Not to mention the fact that each piece of software could only run on the computer for which it was created. However, operating systems were created to change that.

Functions of Operating Systems (OS)

There are various functions conducted by OS in order to achieve specific objectives. These objectives include:

• Memory Management. To run a process, it must first be loaded into the main memory where it will be executed. The memory is released after the process is finished and it can be used for other things. Thus, managing memory via allocating and deallocating it for the processes is the responsibility of the OS.
• Process Management. CPU (one of the resources managed by OS) usually has a number of processes in the ready state at any given time. A processor, on the other hand, can only manage one process at a time. Thus, a CPU uses various techniques to ensure that operations have constant and uninterrupted access to resources. These techniques include first-come, first-serve, round-robin, shortest job first, priority scheduling, and so on.
• File Management. Every computer has its own set of files, folders, and directory structures. The OS of the computer maintains and manages all of these. To keep track of the information of these files, a File Allocation Table (FAT) is used. The FAT keeps track of every detail of the file, including its name, size, type, and so on. Besides, the OS is also responsible for ensuring that the files are not opened by unauthorized people.
• I/O Device Management. There are various I/O devices in a system. Diverse procedures require access to these devices, however, the processes should not access these devices directly. Therefore, it is the responsibility of the OS to manage access authorization of I/O devices.
• Virtual Memory. When the application's size surpasses the main memory, the OS is in charge of loading just the most frequently used pages into the main memory.

Most Popular Computer Operating Systems (OS)

• Microsoft Windows – the most popular and frequently used operating system on computers. It runs on PCs and IBM-compatible systems.
• macOS – Apple's main operating system, which runs on both desktops computers and laptops.
• Linux – an open-source operating system that can be installed on PCs and IBM-compatible systems. It is used to generate a variety of Linux distributions, including Debian, Ubuntu, Slackware, and Red Hat.
• Chrome OS – the operating system that is pre-installed on Google Chromebooks.

Mobile Device Operating Systems (OS)

• Android – the most widely used OS of the majority of well-known smartphone and tablet brands, except Apple.
• iOS – the OS of Apple smartphones and tablets.