Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420.1 (KHTML, like Gecko) Version/3.0 Mobile/4A93 Safari/419.3)
you can limit how much time machine uses by creating a partition on the external disk using disk utility. Alternatively you can let time machine use r
the whole disk and it will eventually fill it up completely. You can put other files on a time machine disk - time machine just stores its files in a directory off the root directory