I purchased an external drive with the intent of using one partition on it to house any and all development related tools. I plan on moving this drive between my iMac and my MacBook. The idea was to have the development environment completely contained within the partition of the external drive. However, I briefly read the XCode installation instruction and came across mention of the fact that the installation process does stash some items in /usr. Is what I'm trying to do here even feasible? I have to think that it is. I would like to install Xcode to this external partition on the MacBook but I also realize that I would have to somehow make the iMac "aware" of the applications on the external partition. Comments?