A cache is a reserved storage location that gathers temporary data to help websites, browsers, and applications load faster. Even if it’s a laptop or phone, application, or web browser, you will find some variety of a cache. A cache makes it easy to swiftly retrieve data, which in turn helps devices run faster. It acts as a memory bank, making it easy to access data locally rather than re-downloading it every time you visit a website or open an application.
HOW DOES CACHE DATA WORK?
Cache data works by storing data for re-access in the memory of your device right below the central processing unit. It is stored in a few layers:
- With the main cache level built into a device’s microprocessor chip
- With two or more secondary levels that feed the main level
Cached data is stored until it’s time to go live or until the device’s hard drive cache fills up. Data is cached in two ways, through the browser and memory caching or through content delivery networks (CDN).
BROWSER AND MEMORY CACHING
A memory data cache stores data on the device that an application or browser runs on. When the browser is active, the resources it retrieves are stored in its random access memory or its hard drive. The next time the resources are required to load a webpage, the browser pulls them from the cache rather than from a remote server which makes it faster to retrieve resources and load the page.
CONTENT DELIVERY NETWORK (CDN)
Caching is one of the CDN’s jobs. It stores data in geographically distributed locations to reduce load times, protect against cyberattacks, and handle vast amounts of traffic. Browser requests get routed to a local CDN which shortens the distance that response data travels and transfers resources fast
THE BENEFITS OF CACHING
1. From a user standpoint, there are three primary benefits to caches:
A cache makes everything run faster and it improves the performance of the system.
2. By storing local copies of website files, your browser only needs to download that information the first time someone visits and can load the local files on subsequent visits.
3. A cache saves data. To help improve performance, applications store recently and frequently used data to the cache data. Not only does this allow everything to run quicker, but also, in some cases, it enables applications to work “offline.” For example, if you don’t have internet access, an application can rely on cached data to continue to work even without a connection.
Caches store data for later use, so there is a lot of efficiency in only downloading files once. If a copy of a file is stored in cached data, then the application doesn’t need to rely on battery power and other resources when downloading it a second time. Instead, the application only requires downloading changed or new files.
DOWNSIDES OF CACHE DATA
Cache data has some disadvantages as well:
The cache can take up a lot of storage space. Basically, cache data is a little repository of files used by an application. But some cache data can grow large and limit the free space on your device. Cleaning the cache can delete the files and restore a large amount of memory.
Corrupted cache data can cause the application to behave poorly. If there’s something wrong with a file stored in cached data, it can cause the application to display data incorrectly or even crash. That’s why a common remedy for browser issues is cleaning the cached data.
Cache data can prevent applications from loading the latest version of a web page or other data. In theory, applications are supported to use the cached data to display files unchanged since the last visit. That does not always work though, and sometimes the only way to see the latest version of a website or other information is to clear the cached data, so the application is forced to download everything anew.
CACHE-CONTROL POLICIES AND SEO
Since systems like HTTP or content delivery networks as Cloudflare cache the resources arbitrarily, they need to know what should be cached and for how long. HTTP uses “cache request and response directives” to control the cache data policies. For example, if there is a component on a website that needs to be uploaded every time someone adds a post, then a directive of “Cache-Control: must-revalidate” should be used anytime someone updates that post. Since search engines crawl and retrieve information all the time, one of the things that they recommend is using better HTTP cache policies for static content. Using cache policies not only provides a better user experience but also can be a key element in aiding the SEO of your website.
In conclusion, caching can introduce some paradoxical situations, and it also presents so many opportunities when it comes to user experience and SEO. Use it wisely!
