9.6 An operating system supports a paged virtual memory. The central processor has a cycle time of 1 microsecond. It costs an additional 1 microsecond to access a page other than the current one. Pages have 1,000 words, and the paging device is a drum that rotates at 3,000 revolutions per minute and transfers 1 million words per second. The following statistical measurements were obtained from the svstem: One percent of all instructions executed accessed a page other than Of the instructions that accessed another page, 80 percent accessed When a new page was required, the replaced page was modified 50 . the current page a page already in memory percent of the time . Calculate the effective instruction time on this system, assuming that the system is running one process only and that the processor is idle during drum transfers