Web servers are specialized computers that are designed specifically for making websites available to your website visitors.
While hardware for web servers can vary drastically, web servers that are designed for internet use typically are more powerful than your average desktop computer, and are optimized for handing a lot of incoming requests for web pages, and storing the related content (files, databases, etc.).
Since quick access to web pages is important, faster RAM, hard drives and processors are typically used. To handle large quantities of data, bigger hard drives, more RAM, and more processor cores are typically utilized as well.
Although web servers usually have better hardware, what really makes a computer or server a "web server" is the software.
At its core, web server software responds to requests from web browsers for resources such as web pages, images and videos. Without the core web server software, people would not be able to request your website or video via the internet.
Going beyond the core function of web server software, modern hosting companies provide additional tools that make it easier for you to make your website available via the internet. For example, hosting control panels and script installation utilities allow you to create and manage your website without having to log into a command line interface (CLI).
Reliable Redundant Fast Internet Connections
In addition to the hardware and software, there is one more important component that is very important: redundant high speed internet access. Without a reliable internet connection, the web server cannot deliver your web pages, videos and other content to your visitors. Quality web hosts provide redundant internet connections to ensure that your website stays available.
All these components are necessary, and is what makes your website available on the internet.