I want to buy a server.where i want to load everything unix,windows,all ETL...

...tools,all Testing Tools,SAP every? I want to buy a server.where i want to load everything unix,windows,all ETL tools,all Testing Tools,SAP ..So which one is the best one to buy and what is the good site in U.S to buy?

You don't want a server unless you are going to connect several computers to one central hard drive.

I think what you want is a computer with enough hard drive space to make several partitions, and install a different operating system into each partition, so that when you boot your computer, you can pick which OS you will start up.

They can't all be running simultaneously, even on a server. When you want to change to a different OS, you have to reboot the system and select the OS you want to boot into.

OR you can buy a dozen or so computers, one for each OS, and just surround yourself with keyboards and monitors.

you can buy one server and run virtual machines of different Operating systems/software on it. (vmware/XEN/...)

The sever should have lots of memory and multiple CPU's.