top of page
Operating Systems

Applied IT (Year 11) - Hardware (U1)

Jeckmen Wu

The Purpose of an Operating System (OS)

The operating system coordinates the operation of the computer’s hardware (including memory, processors, storage, peripherals, ports, connectors) and its included software. In other words, it serves as a vital link between hardware and software.

Functions of an Operating System

1. User Interface

Provides an “environment” within which users can interact with their computer. In modern computers, this is commonly in the form of a graphical user interface, with windows, icons, menus, and a pointer (WIMP), rather than a text-based UI which uses written commands. Therefore, an OS is responsible for building a communication bridge that allows users to enter and receive information to and from their device.  

2. Managing System Resources

Controls the allocation & deallocation of hardware resources, such as the processor (CPU), memory (RAM), storage, network connections, and input/output devices, to ensure each program has sufficient resources to run efficiently, especially when multiple applications or processes are being executed at the same time.

For example, with the limited amount of RAM available on computers, the OS needs to determine the appropriate amount for a task, allocate it, and then deallocate it once it has ended or been terminated in order to free up space for something else. A similar process applies with the processing unit.

The OS is also in control of all the devices connected to the computer. In the case of a printer, for example, it will send through the information to be printed and create a buffer management to handle multiple requests for printing.  

3. Managing Security & Access Rights

Protects user data against unauthorised access by implementing various security mechanisms. This includes access control by requiring login identification credentials (e.g. username, password, touch/face ID) to access the requested resource, network security using firewalls and encryption, and malware protection through antivirus software.  

4. Running Applications

Provides a platform, or a standard interface, to run a variety of applications. By removing the need for applications to directly interact with the hardware, programmers will only need to write the code for a specific OS, instead of a specific hardware in each different model of computer. Hence, an OS is essential for the flexibility and interoperability of a particular application. 

Here are some handy descriptors you can use to explain OS: coordinator or manager (of operations, resources and security); environment or platform (for applications); and intermediary, link, bridge or translator (between user and computer, software and hardware). 

Types of Operating Systems


By far the most used operating system in the world, Windows is a proprietary OS developed by Microsoft that is known for its user-friendly interface and wide software compatibility that offers users access to most programs. However, Windows has and continues to be frequently criticised for its susceptibility to malware and viruses which can be partly accounted for by its large user base. 

Mac OS

Apple’s Unix-based OS similarly boasts a user-friendly platform but one that is equipped with a higher standard of security due to Mac OS’s more rigorous security measures and closed architecture. This means Apple has more control over the security standard of software developed for the platform, evident by the App Store.

However, while the limited compatibility of Mac OS can be a security perk by reducing the risk of cross-platform attacks and malware, it restricts access to the number of software and becomes a huge disadvantage for users requiring any Windows-specific applications.  


Offers a similar experience as the Mac OS, but for Apple’s mobile devices (e.g. iPhone, iPad, iPod). The highly exclusive Apple ecosystem created by the Mac OS and iOS (and watchOS) offers seamless interconnectivity between all its devices (e.g. AirDrop, Find My) but at the expense of restricted compatibility.


The main alternative mobile operating system to iOS developed by Google. It is an open-source operating system that affords a high level of customisability (e.g. third-party custom launchers), but which subsequently makes it vulnerable to security threats. 


An open-source OS that allows users to freely modify and distribute the source code. This is perfect for IT professionals who need to tailor the OS to meet their specific needs.

Linux is also known for being extremely secure due to its integration of user permission, built-in firewalls and a large online community of active developers/maintainers who constantly monitor and improve the OS. Additionally, the size of its user base is very small (especially when compared to that of Windows), allowing it to benefit from “security through obscurity”.

The customisability and security features make it a popular choice for servers and supercomputers. However, it is not particularly user-friendly due to the steep learning curve, limited support, and minimal software compatibility.

bottom of page