Cloud storage is an online service that stores your files on remote servers instead of on a local device. A remote server is a powerful computer in a data centre, owned by the cloud provider rather than by you.
Local storage, such as a hard drive or USB stick, keeps files on the device itself. With cloud storage, files are held on the provider's servers instead, so your own device does not need the space to keep them. Your device sends a request over an internet connection, and the server sends the file back.
For example, if you write a script for a school play on the computer in the drama hall, saving it locally keeps it on that computer only. Saving it to cloud storage uploads it to the provider's server, so you can open the same script later on your tablet at home, without copying it across on a USB stick.
Cloud storage keeps your files on remote servers, so you need an internet connection to reach them. Without one, you cannot upload, download or open the files held in the cloud.
Because your files are stored online rather than on one machine, any internet-connected device can reach them — a library computer, a tablet at home, or a phone in a café. The service itself runs 24/7, so you can work whenever it suits you, as long as you have a connection.
It must be an internet connection, not just your home Wi-Fi: mobile data works too.
The speed and reliability of your connection affect how quickly files move. A fast, stable link transfers files in seconds, while a slow or patchy one makes large files frustrating to work with.
For example, a 500 MB folder of project files takes about 40 seconds to download on a 100 Mbps connection, but roughly 6 minutes 40 seconds on a 10 Mbps one. If the connection drops part-way through, the transfer may fail and you would have to start it again.
When you share a file or folder from cloud storage, you decide what other people are allowed to do with it. These permissions are called access rights. They protect your work from accidental changes or deletion, while still letting the right people see or use it.
| Access right | What it allows | When you might use it |
|---|---|---|
| View-only | Open, read and download the file, but not change it. | Sharing a finished timetable or a set of rules that must stay the same. |
| View and edit | Open, change and save the file. | Working together on a document, such as a drama club writing its script. |
| Full control | Edit, rename, move and delete the file or folder. | Giving a trusted co-organiser more power over the folder — but deleting removes the files for everyone. |
Full control is the highest level because it includes deleting. If you only need someone to read a file, view-only is safer: a mistake cannot ruin the original. You set the rights as you share, and you can change or remove them at any time.
For example, a school photography club stores its event photos in a shared folder. The whole club gets view-only access so they can look at the pictures, the club leader gets view and edit to upload new albums, and a private link to the best photos is sent to the school newsletter team.
Collaboration in cloud storage means several people can open and edit the same file at the same time. Their changes appear almost instantly for everyone, so you can work together without emailing versions back and forth.
Synchronisation is the automatic process that keeps files the same on the cloud and on every device linked to your account. When you save a change on one device, it is uploaded to the cloud and then downloaded to your other devices.
For example, four students in a robotics club keep a shared build log in the cloud. One types the list of parts, another adds the measurements, and a third writes about the motor that kept jamming. Everyone sees the new text as it is typed, so nobody is working on an old copy. This works because the file itself lives in the cloud rather than on one person's device.
Imagine you start drafting a speech for a debate competition on a library computer. You save it, and synchronisation copies it to the cloud. Later, you open the same file on a laptop at home and add a new paragraph. That change is uploaded to the cloud and then copied back to the library computer the next time it is online. You always work on the most recent version, whichever device you pick up.
Synchronisation also means copies of your files sit on several devices, not just one. If one device breaks, your work is still in the cloud and on your other devices.
Version history is a feature of cloud storage that keeps a record of every saved change made to a file. Each time you or someone else edits and saves the file, the service stores a new version. You can then look back at earlier versions and restore one if you need to.
This is useful when a mistake has been made, such as deleting a whole paragraph of your history essay by accident and saving the file. Instead of retyping everything, you open the version history, find the version from before the deletion, and restore it. The same applies if a collaborator makes an unwanted change, like replacing your carefully chosen image with a different one.
When you restore an old version, the service does not delete the newer versions. Instead, it creates a new version that matches the old one, so your version history stays complete. You can usually see a list of versions with dates, times and the names of the people who edited the file.
| Version | Saved by | Change |
|---|---|---|
| 1 | You | First draft of the poster text |
| 2 | You | Added a paragraph about the school garden |
| 3 | Your partner | Deleted the paragraph by mistake |
| 4 | You | Restored version 2, so the paragraph is back; versions 1 to 3 are still listed |
Some cloud services let you keep working when you have no internet connection. This is called offline access. Your device keeps a local copy of the files you have chosen to make available offline, so you can open and edit them even when you are out of signal.
When you edit a file offline, the changes are saved on your device first, and your device records that the file has changed since it was last synced. The next time your device has an internet connection, it synchronises with the cloud. Your edits are uploaded to the cloud copy, and any changes made elsewhere are downloaded, so every device ends up with the same version.
For example, Dhruv is on a school bus with no signal and adds notes to a project file he made available offline. The edits stay on his tablet. When he gets home and connects to the internet, the file synchronises, and his teammates see the new notes on their devices.
Offline access does not mean cloud storage works without the internet. You still need an internet connection at some point to synchronise your changes with the cloud and other devices, and you normally need to have made the file available offline while you had a connection. Until then, the cloud copy stays out of date and other people cannot see your work.
Cloud storage services usually start you on a free basic plan. That plan gives a limited amount of space, such as 5 GB, and a limited set of features. When you need more room, you pay for extra capacity, normally as a subscription that renews regularly.
Scalability means you can increase or decrease your storage easily as your needs change. If your needs grow, you move to a bigger plan. If they shrink, you drop back down. For example, a community radio station might keep 4 GB of interview recordings on the free plan, upgrade to 200 GB while editing a documentary series, then drop back to the free plan once the series has aired.
Scalability keeps costs under control. You only pay for the storage you actually use, so you do not buy a large hard drive that sits empty for most of the year. Paying a small subscription during busy months and nothing during quiet months is cost effective, and being able to step back down matters as much as being able to step up when you only need extra space for a short time.
Cloud storage is not usually offered with unlimited space. Even paid plans have a maximum capacity, so "unlimited storage" is not a standard benefit to claim.
Using cloud storage means you do not need to buy extra hardware to store your files, and you do not have to look after it. The cloud storage provider owns and manages all the physical equipment, so that job is taken care of for you.
If you keep lots of files on a local device, you might need to buy extra storage, such as an external hard drive, a USB flash drive, or even your own server. These cost money and take up space. With cloud storage, the provider has already bought the servers and hard drives, and you simply use them through an internet connection. For example, a community radio station records hours of interviews every month. Instead of buying a large external drive that could fill up or break, the station uploads the recordings to a cloud service, so the provider's hardware stores them and the station buys no storage equipment.
Maintaining storage hardware means checking it works, replacing broken parts, and upgrading when it gets full. It also involves power, cooling, and physical security. The cloud provider does all of this, so you do not have to. Software updates for the cloud storage service are managed by the provider too, so you do not need to download or install new versions or patches. The radio station never has to update the cloud storage app; the provider does it automatically, so the service keeps working without any effort from the station.