What are Cookies, Cache and their Different Types?

Cache and Cookies are two different forms of temporary storage that you’ll find on your system. These are said to improve user experiences on system but they serve different purposes. Both Cache and Cookies store data that can be accessed by third-party sites when we use a web browser. Therefore, it is important to understand what Cookies and Cache are? How are Cache and Cookies different? What are its different types and are Cookies and Cache really harmful?

What are Cookies?

Cookies are small harmless files downloaded on your computer when you visit a website. They have a certain life span well defined by the creator. Cookies can store present & previous online activity, site preferences, passwords, history, etc. This is done to enhance the user experience, so that when the site is revisited page loads quickly.

Often third parties use Cookies to track user online activity and show personalized ads. Hence, considered as a security concern but because of Cookies World Wide Web works the way it does. However, from the security point of view, you should configure browser settings to not accept cookies or delete cookies when exiting the web browser.

What is Cache Memory and Web Cache?

Cache Memory popularly pronounced as Cash is the volatile computer memory. It stores all recent instructions and boosts processing time. Cache stores the input is given by the user to perform a Task.

Whereas the other form of Cache i.e. Browser cache, web cache or temporary Internet files is a collection of data (website images, documents, etc.) downloaded, to support viewing and display of web page. This stored information helps to load web page faster as some, information of each page you visited earlier does not need to re-downloaded from the server as stored in Cache. Thus, reducing webpage’s load time.

But web Cache has a shortcoming while your browser is loading stored information there’s a possibility that website might have changed its data. Therefore, clearing browser cache every few weeks is recommended. Or if you want you can configure browser settings to delete browser cache each time you exit the web browser.

What is the difference between Cookies and Cache?

Although Cookies and Cache both store user data. Both Cookies and Cache serve different purposes and hence are different

– Cookies are used to save user information to track online behavior while Cache increases web page load time.

– Cookies store information while Cache keeps files like music, video, and others.

– Cookies have a life span, they expire after time while Cache is saved on the user’s machine until they are manually removed.

Now, that we have understood the difference between Cookies and Cache. Let’s proceed to know about different types of Cookies and Cache.

Different Types of Cookies and Cache

Both Cookies and Cache have different types and each has different characteristics. Therefore, it is important to know about them. So here we enlist types of Cookies and Cache.

Types of Cookies

There are three types of Cookies stored on your computer. They are Session Cookies, Persistent Cookies, and Third-Party Cookies. All these three Cookies differ from another in characteristics and the way they work. But one thing is common i.e. the very basic nature – Cookies are made to collect, track and store data requested by the site you visit.

Session Cookies:

These are temporary Cookies and they remember your online activities. For a website to work these Cookies are vital because Session Cookies work as a memory for the website. If there are no session Cookies then your website history will always be blank. Moreover, each click you make would be treated as a new visitor.

To make you understand how session Cookies are helpful let’s take an example of online shopping. When shopping online, you add an item in the cart and proceed this item remains there. But how? This is because of session Cookies, as it helps the website remember your action. Without them, your cart would be empty when you reach the check-out page.

Note: Session Cookies expire as you close a web page.

Persistent Cookies:

Persistent Cookies, permanent and stored cookies are the terms used interchangeably. These are also known as first-party Cookies and they track your online preferences. When you visit a site for the first time, it loads at its default settings. When you make any changes to it to fit your preferences, persistent Cookies help computer remember and implement those preferences when you revisit the site.

These Cookies make remembering login information, language selection, bookmarks, etc. possible. Persistent Cookies are stored in the hard disk drive typically for a longer duration. Expiry of these cookies vary depending on the expiration date, once reached these Cookies are expired and your website settings return to default.

Third Party Cookies

Referred to as tracking Cookies, these Cookies collect data based on your online activities. When you visit or revisit a site third party collects these Cookies to study your behavior. Often these Cookies are sold to advertisers by the website who creates them. This helps advertisers show personalized ads.

Third Party Cookies serve as a useful purpose for marketers but for users it might be a privacy concern. That is the reason why most of the website gives the option to block these Cookies.

Types of Cache

All Cache serves the same purpose but we can divide them on the basis of the place they get stored. As we know Cache is broadly divided as Memory Cache and Web Cache. So are its types. So here, we will first discuss types of Memory Cache then Web Cache.

Remember we won’t be discussing much of the technical details as it might confuse you.

Memory Cache and its types

Types of Cache

1. Primary Cache
2. Secondary Cache
3. Main Memory

1. Primary Cache or L1:

As compared with other memory Cache, primary Cache is small and it is computer processor dependent. Usually, the size of the primary cache is between 2KB – 64KB. Primary Cache is an embedded register in the CPU. Instructions required by the CPU are searched in L1 Cache.

2. Secondary Cache or L2:

As the name says it is a secondary Cache and is more spacious as compared to primary Cache. Secondary Cache size is between 256KB – 512 KB and is located on the computer microprocessor. If the instructions are not found on L1 they are then searched on L2 Cache by the microprocessor.

3. Main Memory or L3:

Main memory is slower than L1 and L2 and its size is between 1MB – 8MB. Main memory is double the speed of RAM. Unlike separate L1 and L2, all core shares a common L3 cache.

Web Cache and its types

Level 1: Browser Cache:

Browser Cache or Personal Cache is used by all the modern browsers (Google Chrome, IE and Firefox). This Cache works on simple rules and stores a specific amount of web objects on your hard disk. For example, when you hit the back button while browsing, the page gets loaded using the information stored in Browser Cache rather than resending the request to web server.

Level 2: Proxy Cache: Like Browser Cache, Proxy Cache too works on the same principle but they server large number of users. Proxy Cache is the link between client and web server, it keeps a check on the request for HTML pages, images, etc and store a copy of them. This is done to decrease the page load time. Secondly, it serves as resource optimization. A most common example of caching proxy server are Apache, Nginx, and Varnish.

Besides this, there are Caching mechanism too but we won’t be going into that depth as it will confuse you. The only thing you need to remember here is Caching in an integral part of web technology and optimization of website and computer is important to get high performance.

Hope certain of your doubts related to Cookies and Cache were cleared and you now know why are they used and stored.

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