IFS is a reality. There is detailed info on it somewhere on the forum.
Just for the record, the balance of your time in the Reserves would be in what is called the Individual Ready Reserve, IRR. We sometimes get guys that question the orders because they were told six after wings. The IRR comittment is the balance of the total 8 years owed the Navy as ea6bflyer notes. You would be off active duty and esentially your name is kept on a list. No drills, no haircuts, no pay, no responsiblities, unless there is a national emergency and then it takes a "presidential call up" (read WWIII). If you want to continue your Navy career as a weekend warrior then you become a Selected Reserve, or SELRES.