I'm planning to set up a domain controller for our small computer laboratory. I'm a little confused as to what operating system to use for our domain controller.

What's in the lab:

• The lab has 25 units running a mix of Windows 7 and Windows XP.
• The domain controller will only have 2GB of RAM running a C2D E7200. (Is this enough?)

What we want:

• The Domain Controller will also be running a git server.
• The Domain Controller will also be used as a general development machine (mostly Java, PHP).
• A way to centralize the updates for the windows clients, so that they won't have to download the same patches from the remote site. The machines would just query them from the local domain controller and get the updates from there.

Our head recommended that I virtualize a Windows Server 2008 system under a Linux host and use the former as a domain controller and the latter for development or the other way around.

A comparison of the advantages and disadvantages of using a Linux distribution or Windows Server 2008 in this situation would also be appreciated.

As you may have noticed by now, I'm kinda new to setting up a domain so I hope you guys will be able to help me. Thank you.