What is a cache? Uses, types and what happens when you clear it

Definition of cache

In non-computing contexts, a “cache” refers to a secure hiding or storage place. This original meaning is also helpful in understanding the purpose of a cache in computing: a temporary storage location for data. It serves as a memory bank for information that was previously retrieved, storing it in a place where it can be accessed quickly without long download times.  It is most likely that you have encountered the word “cache” in the context of internet browsing. Web browsers have a cache for the HTML files, JavaScript and images that make up a website, so if you return to a specific website frequently it can access this data from its cache instead of redownloading it every time. This is useful because the website can load more quickly.

Why you might need to clear a cache

With this in mind, why are we sometimes advised to clear the cache of a device, browser or other application? A cache sometimes reaches its memory limit, and a full cache can cause an app to crash or not load correctly. These problems can also be caused by a corrupted file in app’s cache. And while a web browser or other app is only supposed to display files from the cache if they are unchanged since the last visit, this sometimes does not work, and you don't see the latest version. As a cache grows, it also can take up a lot of storage space and limit the free space on a device.

All of these problems and glitches can be corrected by clearing the cache, which frees memory space and deletes old data. Brower caches may also contain personal information that you have entered into online forms, like addresses or even passwords, which can pose a security threat if you are using a shared or public computer.

For these reasons, it can be a good idea to clear a cache periodically – however, it is not recommended to do so on a daily basis. Frequent clearing of the cache will rob you of the benefits of quick data access. Most caches are set up to delete files automatically after a certain period of time. However, if you are experiencing the sort of problems or security issues described above, you may be able to solve them by manually clearing your cache. This will most frequently occur with a web browser.

How to clear your browser cache

It is possible to clear the cache in a browser in a few clicks by going to the settings. The steps for clearing a cache are not exactly the same for every browser type, but they are generally similar. For example, to clear the cache in Chrome:

1. Open the Google Chrome browser on your computer.
2. Click More icon (three dots) at the top right. A drop-down menu appears.
3. Click More Tools > Clear Browsing Data. A pop-up menu appears.
4. To delete all data from the cache, select All time. 
5. Check the boxes next to Cookies and other site data and Cached images and files.
6. Click Clear data.

For additional information on your specific internet browser, you can visit the browser support site or check our Help Center: Clearing the Cache

What happens after you clear a browser cache?

As noted, one purpose of a browser cache is to speed up performance. So after you clear the cache, some sites may initially seem slower because content such as images needs to load again. Some settings on websites, e.g. logins or forms you had filled in, will be deleted. The next time you visit these sites, you’ll have to enter the information manually again.

   

Browser caches are not the only types of cache

Caches serve a similar purpose in many different types of applications and hardware: Allowing data to be reused quickly and efficiently. In addition to a browser cache, places you’ll find a cache include:

• Your computer or mobile device: Its CPU has its own cache, a small block of memory where it stores frequently used information. Reading data from this memory is much quicker than reading it from disk, so this can improve overall performance of applications and make executing your instructions faster.
• Apps: Here the cache saves files and data so the app can quickly reload information – this could include images, search history or user preferences. Sometimes this cached data can allow apps to continue to work offline if internet access is interrupted. And when a file is cached, the app doesn’t need to waste time or battery power downloading it a second time.
• DNS servers: When you type a URL (website address) into your browser, this request is sent to a domain name system (DNS) server that converts the URL into an IP address. DNS servers store recent lookups in their cache, letting them reply instantly with the IP address of a domain.
• Search engines: The software may cache frequently searched webpages. This lets the search engine answer your search query even if the website it is trying to access is temporarily unavailable.

What is email cache and why you might need to clear it

An email cache is used to keep the information from your email stored so that you have a faster loading/downloading time. It operates as a memory storage that gives you the ease of having faster file access. This can be loading already opened emails faster when you’re in the middle of recalling information. Or it can be having files more accessible in your inbox. If you do not regularly clear your email cache, you will have lack of space and lose track of the convenience in file access. Your email cache should be emptied to ensure your data protection and to free up used storage space for more important files.
 
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This article first appeared on February 6, 2022 and was updated on March 2, 2023
Images:  1&1/Shutterstock