The term “server” does not make a clear distinction between software and hardware. It often refers to computers on which services are made available. However, multiple software servers, such as mail servers, application servers or web servers, can be easily installed on one single server computer or server system. Server hardware is characterised by special features. These may include a large internal memory, large hard disk space, powerful CPUs or high I/O throughput and high reliability. In most cases, systems run 24/7.
There are various types of server available. Virtual servers are not assigned to any particular hardware. They consist of multiple software servers that are installed on a host or host system and act like independent servers vis-à-vis the user. Dedicated servers, on the other hand, are assigned to a specific device or module. This means that the resources do not have to be shared with other server systems. A so-called shared server is one that is not intended for the exclusive use of a particular customer or for an individual task.