What do you mean by memory fragmentation? Distinguish between the internal and external fragmentation.

When a process request the memory space, if the requested memory space is greater than the memory needed by the process then a tiny hole is created which is called memory fragmentation. For example if the process request for 812bytes. If whole memory is allowed to the process, a tiny hole of 3 bytes is created which is called memory fragmentation.

The difference between the internal and external fragmentation is given below:

•   Internal fragmentation is occurred in paging while the external fragmentation is occurred
  in fragmentation.
  
•   When process request for memory segment and if the available memory is greater than
  the memory needed for process, a tiny hole is created and the difference between these
  two space is called the internal fragmentation.
  
•   While if a process request for memory size and if the process does not get the exactly the
  memory as it needed to complete its execution. This is called external fragmentation. Here, the holes are smaller than the memory needed by the process. This can be satisfied by the memory compaction and coal siding.