What Is Cache and Here is All You Need to Know

Charlene updated on Dec 13, 2022 to Knowledge Center

What Is Cache (Computing)

A cache is a temporary storage for recently accessed data in a computing environment like web browsers or applications. More like a memory bank, you wouldn't need to download the already-cached data again because it can be accessed locally whenever you need it. 

what is cache

It makes data retrieval easy and is used because the primary storage cannot keep up with the client's demands. In addition, it decreases access times, improves input or output (I/O), and reduces latency. Generally, it improves application performance because almost all app workloads depend on I/O operations.

Depending on your purpose, specific types of caches apply to some particular purpose. Some of them are:

  • Cache memory
  • CPU cache
  • Proxy cache
  • RAM cache
  • Persistent cache
  • Flash cache
  • Disk cache

Cache memory

You may ask, "what is cached memory"; it is RAM that the CPU can access faster than your regular RAM. This type of cache is faster than the disk-based or RAM cache because of its association with the CPU.

CPU cache

This cache is much faster than the RAM because the memory operates at the same rate as the CPU speed as the system bus speed. It is a tiny part of the memory placed on your CPU.

Proxy cache

A proxy cache is called a Cache Server because it deals locally with webpages and other internet data. In addition, it is a dedicated service or server.

RAM cache

This is related to the physical RAM embedded and installed on the motherboard's attachment locations or dedicated slot. Access to this memory is faster than the magnetic media and is made possible through the mainboard bus. However, the CPU cache memory is between 10 to 100 times faster than it.

Persistent cache

Even when your system reboots or crashes, this type of cache does not lose data because it uses a battery backup to protect data in case of any eventualities. Data is flushed and kept in a battery-backed (dynamic) RAM as added protection against data loss.

Flash cache

Another type of cache, also known as Solid-state drive cache, uses the NAND flash memory chips for temporary data storage. This type of cache grants data requests faster when compared to a cache stored as part of the backing store or on an HDD.

Disk cache

Lastly, the disk cache holds recently accessed data that will likely be read soon. It works based on how frequently the data is accessed. Frequently read storage blocks (Hot blocks) in this cache are automatically sent as cached data.

What Does the Cache Do and How It Works

As explained in the previous section, a cache acts more like a reserved storage for recently accessed data to enable quick and easy retrieval of those data when needed by an application or web browser.

When an application attempts to access recently retrieved data and finds it in the cache, it is said to have made a cache hit. The ratio of cache hits out of total attempts to access data is called Cache hit rate. In case of a cache miss (requested data missing in cache), data is pulled from memory and copied into the cache; this depends on the cache protocols, algorithms, and system policies in place.

In line with this, when you visit a web page using popular web browsers such as Firefox and Chrome, your browser uses caching to improve the performance of frequently or recently accessed web pages.

This is known as reading cache, meaning the browser can access data faster from the browser cache than the webpage. This results in higher performance and reduces data latency. In addition, it gets most of the files from the cache memory rather than resending them from the web server.

Benefits of Caches

Having looked at how caches work and what they do, let's look at the several benefits of caches.

Resource efficiency

Utilizing caches helps conserve resources, time, and energy consumed by your device due to fast access to recently retrieved information. The only time your application will need to download new files is when such information changes.

Offline work

Without internet access, your application can rely on cached images and files to work or fill in the needed data that was recently accessed. However, the cache may only supply some of the required information or functions.

Performance

Lastly, this is the significant benefit of caches; they make everything run faster than usual. Your applications or web browsers only need to download such information on the first visit, after which it is loaded from local files subsequently.

Drawbacks of Caches

Even though the benefits of caches seem catchy, they have their drawbacks. Let's dive right in.

Performance

Yes, caches can affect performance because they are small reserved stores, which, when significant, can affect the general application performance to degrade. They can affect the memory needed by other applications, therefore causing an underperformance for different applications.

Corruption

If caches get corrupted, they become useless and can cause applications to display incorrect data or crash.

Outdated information

Caches can cause glitches or fill in misleading information from a previous session on updated websites or applications. This is a problem with dynamic content, unlike static content, which does not change with time.

What Does It Mean to Clear the Cache

The drawbacks of caches call for seasonal clearing to keep its information updated and avoid underperformance caused by large caches. Clear cache means deleting the old files and possibly replacing them with updated information.

Program owners make the "clear cache" option available in the Settings of the application or web browser. You can also clear the cache on Windows 10/11 to speed up your PC. 

However, as much as clearing the cache is needed to avoid its drawbacks, you must know that you may have to log into all your web pages again. It's worth it if you're already experiencing problems with your system.

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