How to get system drive?

[Raccoon29]

Hi all,

I have to parse the result of a DOS command, and I need that that DOS command is executed on the system drive.
For example if the system drive is "C:\" it must be executed in "C:\" and not "D:\" or "X:\" or what else.
So is there a way to get the system drive?

By the way: if there is an easier way to get the system drive volume serial number, it would be great if he could tell it

Thank you in advance!