There are two major varieties in linux kernels, Server and Desktop.
To know if the system is server, use the command uname -a to know if the system is using a server kernel or a desktop kernel.
To know the version of the Ubuntu, use below command at a terminal prompt.
This command will give an output such as Ubuntu 12.04 LTS, or Ubuntu 13.10.
LTS expands to long term support. 12.04 LTS is supported until the year 2017.