Software — System Software and the Operating System

Two Kinds of Software

As introduced earlier, software falls into two broad categories — system software and application software. Understanding the difference is important because they serve very different purposes.

System Software

System software is the set of programs that run, control, and manage the computer's hardware and provide a platform on which application software can run. The user does not usually buy or run system software to accomplish a specific personal task; rather, it works in the background to make the whole machine usable. The most important piece of system software is the operating system; other examples include device drivers (small programs that let the operating system communicate with a specific piece of hardware, such as a printer) and utility programs (tools for tasks like antivirus scanning, file compression, or disk clean-up).

The Operating System (OS)

The operating system (OS) is the master control program that is loaded first when a computer starts and that manages every other program and all the hardware resources. It acts as the essential link between the user, the application software, and the hardware. Without an operating system, a computer cannot function at all. Common examples of operating systems include Windows, Linux, macOS (for computers), and Android and iOS (for smartphones).

Main functions of an operating system:

1. Process management — starting, running, pausing, and stopping the various programs (processes) running on the computer, and sharing the CPU's time among them.
2. Memory management — allocating memory (RAM) to each running program and reclaiming it when the program finishes, so that programs do not interfere with one another.
3. File management — organising data into files and folders, and controlling how files are created, saved, opened, copied, renamed, and deleted.
4. Device (input/output) management — controlling and coordinating all the input and output devices (keyboard, mouse, printer, disk) through their device drivers.
5. Providing a user interface — giving the user a way to interact with the computer, either through a Graphical User Interface (GUI) of windows, icons, and a mouse pointer, or through a Command Line Interface (CLI) where the user types text commands.
6. Security and access control — protecting the system through user accounts, passwords, and permissions, so that only authorised users can access data and settings.

Application Software

Application software is a program designed to help the user perform a specific, useful task. Unlike system software, application software is chosen and run by the user for a particular purpose. Application software is often grouped as:

• General-purpose (packaged) software — ready-made programs sold to the general public, such as word processors (for documents), spreadsheets (for calculations and tables), presentation software (for slide shows), and web browsers (for accessing the internet). …