PROPERTIES OF REQUEST ARRIVAL PROCESS (fig. 10-3)

• signifies that some data items are likely to be accessed more frequently
• example: in an on-demand movie application, most requests are likely to be for popular and recently released movies
• can be exploited by placement of multimedia data in a storage hierarchy where frequently requested data are assigned faster devices

• depending on the application, the request arrival process can be temporally clustered
• example: in an on-demand movie application, the request rate for popular movies would be higher during weekends than on the weekdays