Virtual Memory Page Space Allocation
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
A method is described for use in a virtual memory data processing system which minimizes arm movement of the disk file when writing (and reading) pages to disk. The performance of a virtual memory system degrades when there is excessive disk arm movement within paging space. Disk affinity at pageout time is obtained by always freeing any slot the page now owns, and re-allocating a slot adjacent to and in the same direction as the last slot allocated, a "slot" being a contiguous logical block on the disk that is the size of one virtual memory page. If there are multiple paging spaces present, then examine the next allocation slot on each paging space, and use the slot that has a disk arm nearest it. The implementation of the above is to keep a cursor per paging space.