A server is a computer that performs a central role within a network. In principle, any computer that offers services to other computers on a network is a server. However, dedicated server machines get far less downtime and therefore have higher specifications than normal desktops or laptops.
Servers perform many tasks, some of the most noticeable include hosting websites, file storage, email handling and multiplayer games. Users work with, or on, a server when opening a website, storing files in the cloud, sending and receiving email, or playing games online.
As corporate servers have to conform to higher standards, they possess hardware components that are less susceptible to errors. Dedicated server hardware has components manufactured to be more compatible with each other, reducing the chance for errors to occur.
Importantly, server computers very often include redundancies. With two or more power supplies, the server can continue running if one fails or a fuse trips. Hard disks at least have a mirrored system or a redundant array of inexpensive disks, or RAID, configuration. The server stays up and running even if one physical hard disk fails. Furthermore, the redundant components are often "hot swappable," meaning that users can replace them as the server runs.