ficant benefits, poses one major problem: What happens if a block is accessed while being moved, swapped, or discarded? GEOS responds to this problem with the implementation of a system for locking and unlocking blocks. When a block is locked on the heap, the Memory Manager may not move, swap, or discard it until it is unlocked. This locking mechanism allows applications to gain control over their memory during periods of access and relinquish it when it is not in active use. Applications, however, should n