Japan’s University of Tokyo has decided to purchase 1,150 iMacs as part of an upgrade that will replace 1,600 computers running Linux that have been in use for five years. The iMacs will be made available to all students, professors and instructors next March. University officials said the decision to go with Macs over PCs came down to a matter of maintenance. Mac OS X, they said, is easier for staff to maintain because of its Unix-based underpinnings.