This counter tallies the physical read I/O operations issued to satisfy page faults, as tracked by the Page statistics group. Admins pair it with the pages-read count to see how many pages, on average, each disk read I/O retrieved, a measure of paging I/O efficiency. For example, if a reporting interval shows 300 pages read via only 40 I/Os, the disk subsystem is clustering roughly 7-8 pages per read, an efficient pattern.