What is internal fragmentation?
Consider holes of 20k assume the process requests 18 bites. If we allocate accurately the request block, we are left with a hole of 2k. The overhead to keep follow of the hole will be considerably larger than the Hole itself. The common approach is to break the main memory in units of block size as with this approach the allocated memory to a process may be slightly larger than he requested memory. The dissimilarity between these two numbers is internal fragmentation (memory internal to a process but cannot be used).
- internal fragmentation: space within every block that is not used totals a substantial amount even when all blocks are used.