Virtual Memory. Early computers had a small and fixed amount to memory. All programs had to be able to fit in this memory. Overlays were used when the program was to big. The programmer was responsible for bringing in the overlays and managing the overlay process.
(a)-(d) Development of external fragmentation.
(e) Removal of the external fragmentation by compaction.
Data structures used in translating virtual addresses on the UltraSPARC.