Sleepers and workaholics: caching strategies in mobile environments
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Adaptive page replacement based on memory reference behavior
SIGMETRICS '97 Proceedings of the 1997 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
EELRU: simple and effective adaptive page replacement
SIGMETRICS '99 Proceedings of the 1999 ACM SIGMETRICS international conference on Measurement and modeling of computer systems
Adaptive modem connection lifetimes
ATEC '99 Proceedings of the annual conference on USENIX Annual Technical Conference
The EELRU adaptive replacement algorithm
Performance Evaluation
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We examine a policy for managing modem pools that disconnects users only if not enough modems are available for other users to connect. Managing the modem pool then becomes a replacement problem, similar to buffer cache management (e.g., in virtual memory systems). When a new connection request is received, the system needs to find a user to "replace". In this paper we examine such demand-disconnect schemes using extensive activity data from actual ISPs. We discuss various replacement policies and propose CIRG: a novel replacement algorithm that is well suited for modem pools. In general, the choice of algorithm is significant. A naive algorithm (e.g., one that randomly replaces any user who has been inactive for a while) incurs many tens of percent more "faults" (i.e., disconnections of users who are likely to want to be active again soon) than the LRU algorithm, which, in turn, incurs 10% more faults than CIRG. For good replacement algorithms, the impact can be significant in terms of resource requirements. We show that the same standards of service as a system that does not disconnect idle users can be achieved with up to 13% fewer modems.