If you have more than 1 computer you can use Synergy to control them with 1 keyboard and 1 mouse as if they were 1 computer, this will work on Windows, Linux and OSX. It can also be configured to auto start so that you get seamless operation from boot up.

You end up with a system which acts exactly the way multi-monitor works on a single computer but over multiple computers, the benfit being you can run processes on each computer so you get more power and different operating systems if that is of use to you as well.

An overview of how to get this working is, you set up the computer with the mouse and keyboard attached as the host, then create rules to define where each screen begins and ends and which ones are to the left / right / top  or bottom of it.

Using Linux and Windows Together with Synergy