Round-Robin Swapping

In an effort to improve performance, Digital changed the OSF paging algorithm to support simultaneous paging to multiple swap partitions. By contrast, OSF paging is to one swap partition at a time, waiting until the first swap partition is filled before moving to the next. As a result, since disk transfer rates are several thousand times slower than the speed of memory and the Alpha CPU, system administrators can greatly reduce this disparity in speed by spreading swap partitions among different disks and different controllers. In fact, by supporting simultaneous paging to multiple swap partitions, Digital UNIX Version 4.0 allows multiple tasks to take simultaneous page faults, thereby further increasing performance.