The Computer Revolution/Hardware/Server
A server is nothing more than a computer that provides services to other computers. In any computer can be a server the only thing you have to do is enable file sharing and others are able to copy files to and from your computer. But the main question is it a good or fast server?, That depends on you machine. There are different types of servers here a list of some basic once: Mail server - a computer optimized to handle email. What could mean it was a lot of hard disk space. Print server - a computer optimized for printing that could mean it had a big hard disk space. Web server - that could be a shared or dedicated. Shared means that it could host more then 1 site and dedicated means that it is only hosting one.
So in conclusion a server is just a computer that's been selected to perform a specific task in service to others and the task that makes the difference.