External and Internal Fragmentation
External Fragmentation – As processes are loaded and removed from memory, the free memory space is broken into little pieces; external fragmentation exists when enough total memory space exists to satisfy a request, but it is not contiguous; hence memory is fragmented into a large set of small holes
Internal Fragmentation – A process is allocated more memory space than it requested because the overhead (to track the small hole that would have remained) is larger than the hole itself