Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Computer Science
16 Dec 2025
141
4 pages
Tara Vidal @taravidal_jrny
Your computer's operating system is like the manager of everything happening inside your device - from running your... Show more
Ever wondered what makes your computer actually work when you click on an app? The operating system is the essential software that provides a platform for running all your programs and managing everything your computer does.
The operating system isn't just one thing - it's an umbrella term covering loads of components. This includes your user interface (what you see and interact with), application management, memory management, file organisation, utility programs, and device drivers. All of this falls under system software, which also includes utility software.
You interact with your computer through different types of user interfaces. The graphical user interface (GUI) is what most of us use daily - it's visual, interactive, and intuitive with windows, icons, and menus optimised for mouse and touch input. There's also natural language interface (like Alexa) that responds to spoken commands, though it's not always reliable and can have security risks.
Remember Menu interfaces (like old iPods) let you choose single options at each stage, whilst command line interfaces are text-based and more efficient for advanced users and automation scripts.
Think you're brilliant at multi-tasking? Well, your computer's got you beat! Multi-tasking is when your operating system runs multiple applications simultaneously by giving each process a tiny slice of time and cycling between them so quickly it appears everything's running at once.
Your computer needs to communicate with all those peripheral devices you've got plugged in - your mouse, speakers, webcam, and printer. Here's where device drivers come in - they're special software programs that translate commands so each specific hardware device can understand them.
The clever bit is that device drivers create a universal version of commands that all similar devices can use. So whether you've got a fancy laser printer or a basic inkjet, the same print command works for both because their device drivers handle the translation.
Key Point Device drivers are what let your operating system talk to any hardware you connect, making everything work together seamlessly.
Your operating system is constantly organising your files behind the scenes, and it's more complex than you might think. Each file has an extension that tells the system which program to open it with, whilst the folder structure lets you rename, move, edit, and delete files easily.
Here's where things get messy - literally. As you save and delete files over time, they become fragmented, which means they get broken up and scattered across your storage. This fragmentation slows down your computer because it takes longer to find and piece together file fragments.
Memory management works similarly - the operating system breaks up programs to fit them in available space, and when memory gets full, it uses virtual memory. To make this more efficient, memory gets divided into equal-sized parts called pages.
The operating system also handles user management, creating different accounts with varying levels of access to files and programs. In client-server setups, users can even access their profiles from different locations on the network.
Pro Tip Regular maintenance like defragmentation helps keep your system running smoothly by reorganising scattered file fragments.
Your operating system comes packed with utility programs that keep everything running smoothly. The main ones you need to know about are encryption (protecting your data), compression (making files smaller), and various security tools like anti-malware, anti-virus, and anti-spyware programs.
Defragmentation utilities are particularly important for traditional hard drives. They reorganise fragmented files by putting the scattered pieces back together and collecting free space, which reduces the movement of the read/write head and speeds up file access.
However, there's one crucial exception - never defragment SSDs because they have no moving parts and work differently from traditional hard drives.
When it comes to backing up your files, incremental backup is a smart approach that only copies new files or files that have changed since your last full backup. It's quicker than full backups but slightly less reliable.
Important Knowing which utilities to use and when can significantly improve your computer's performance and keep your data safe.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Quotes from every main character
English LiteratureApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Tara Vidal
@taravidal_jrny
Your computer's operating system is like the manager of everything happening inside your device - from running your games to managing your files. Understanding how operating systems work will help you make sense of why your computer behaves the way... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ever wondered what makes your computer actually work when you click on an app? The operating system is the essential software that provides a platform for running all your programs and managing everything your computer does.
The operating system isn't just one thing - it's an umbrella term covering loads of components. This includes your user interface (what you see and interact with), application management, memory management, file organisation, utility programs, and device drivers. All of this falls under system software, which also includes utility software.
You interact with your computer through different types of user interfaces. The graphical user interface (GUI) is what most of us use daily - it's visual, interactive, and intuitive with windows, icons, and menus optimised for mouse and touch input. There's also natural language interface (like Alexa) that responds to spoken commands, though it's not always reliable and can have security risks.
Remember: Menu interfaces (like old iPods) let you choose single options at each stage, whilst command line interfaces are text-based and more efficient for advanced users and automation scripts.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Think you're brilliant at multi-tasking? Well, your computer's got you beat! Multi-tasking is when your operating system runs multiple applications simultaneously by giving each process a tiny slice of time and cycling between them so quickly it appears everything's running at once.
Your computer needs to communicate with all those peripheral devices you've got plugged in - your mouse, speakers, webcam, and printer. Here's where device drivers come in - they're special software programs that translate commands so each specific hardware device can understand them.
The clever bit is that device drivers create a universal version of commands that all similar devices can use. So whether you've got a fancy laser printer or a basic inkjet, the same print command works for both because their device drivers handle the translation.
Key Point: Device drivers are what let your operating system talk to any hardware you connect, making everything work together seamlessly.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your operating system is constantly organising your files behind the scenes, and it's more complex than you might think. Each file has an extension that tells the system which program to open it with, whilst the folder structure lets you rename, move, edit, and delete files easily.
Here's where things get messy - literally. As you save and delete files over time, they become fragmented, which means they get broken up and scattered across your storage. This fragmentation slows down your computer because it takes longer to find and piece together file fragments.
Memory management works similarly - the operating system breaks up programs to fit them in available space, and when memory gets full, it uses virtual memory. To make this more efficient, memory gets divided into equal-sized parts called pages.
The operating system also handles user management, creating different accounts with varying levels of access to files and programs. In client-server setups, users can even access their profiles from different locations on the network.
Pro Tip: Regular maintenance like defragmentation helps keep your system running smoothly by reorganising scattered file fragments.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Your operating system comes packed with utility programs that keep everything running smoothly. The main ones you need to know about are encryption (protecting your data), compression (making files smaller), and various security tools like anti-malware, anti-virus, and anti-spyware programs.
Defragmentation utilities are particularly important for traditional hard drives. They reorganise fragmented files by putting the scattered pieces back together and collecting free space, which reduces the movement of the read/write head and speeds up file access.
However, there's one crucial exception - never defragment SSDs because they have no moving parts and work differently from traditional hard drives.
When it comes to backing up your files, incremental backup is a smart approach that only copies new files or files that have changed since your last full backup. It's quicker than full backups but slightly less reliable.
Important: Knowing which utilities to use and when can significantly improve your computer's performance and keep your data safe.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Quotes from every main character
English LiteratureApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology