Linux, in good Unix tradition, is designed to build things in pieces, which can work together. A number of Linux filesystems are designed to be layered on top of other filesystems. One such filesystem is the distributed, fault-tolerant Glusterfs (http://www.gluster.org/). You should be able to layer it on top of a number of other filesystems which can do versioning or snapshots (e.g. ZFS or Btrfs).

My vote would be for teaching the metric system in math and science classes, and teaching the imperial units in history and social studies classes. We should not scrap knowledge of the past. We can respect the fact that the mile and furlong go back to ancient Rome, and make sure children know the history. But at the same time, it would be nice to have a system that is logical.

The problem with converting everything to the metric system is, not everything can be expressed in it using whole numbers. As was pointed out above, a tall person is over 6 feet tall. Maybe people just need to increase their size to an average of 2 meters :-)