Upgrading the service capacity of video-on-demand servers with memory buffer

In this paper, we propose a new approach to exploit semiconductor memory to upgrade the service capacity of video-on-demand systems. The basic idea behind this so-called Gneralized Relay Mechanism is that if we can relay the data of frequently accessed programmes from one access request to another, then we can improve the service capacity of the system without requiring higher disk bandwidth. The design of the Generalized Relay Mechanism is aimed at optimizing allocation and trade-off of the memory resource and the disk bandwidth resource. A simulation-based study shows that the Generalized Relay Mechanism is a very competitive alternative in comparision with simply incorporating more hard disks. If compared with an intuitive approach of utilizing memory buffer that always fills up the memory with most frequently accessed programmes, the Generalized Relay Mechanism enjoys an advantage in terms of cost.