4.2. Legacy Memory Management Schemes

4.2.1. Single Contiguous Allocation



4.2.2. Partitioned Allocation



Strategies for how to satisfy a process request of size n from a list of free holes.


Allocate the first hole that is big enough.


Allocate the smallest hole that is big enough; must search entire list, unless ordered by size. Produces the smallest leftover hole.


Allocate the largest hole; must also search entire list. Produces the largest leftover hole.

4.2.3. Fragmentation

External fragmentation

total memory space exists to satisfy a request, but it is not contiguous

Internal fragmentation

allocated memory may be slightly larger than requested memory; this size difference is memory internal to a partition, but not being used