Difference between Global and Local Page Replacement
Global page replacement
In global replacement a process can select even that frames which is currently allocated to some other process. Thus, in this strategy, one process can take a frame from another process. In global replacement, the number of frames allocated to a process may increase. One problem with this method is that a process cannot control its own page fault rate. The main advantage is that it results in greater system throughput.
Local page replacement
In this algorithm, the replacement frame selected by a process can only be from the set of frames which are allocated to it. The process cannot select the frame which is currently allocated to other process. Thus, one process cannot take a frame from another process in local replacement. In local replacement, the number of frames allocated to a process does not change.
Comparison between Global and local page replacement
| Global page replacement | Local page replacement |
| In this algorithm, the replacement frame selected by a process can be any frame from the set of all frames. | In this algorithm, the replacement frame selected by a process can only be from the set of frames which are allocated to it. |
| A process can select even that frames which is currently allocated to some other process. | A process cannot select the frame which is currently allocated to other process. |