Cache invalidation scheme for mobile computing systems with real-time data

In this paper, we propose a cache invalidation scheme called Invalidation b y Absolute Validity Interval (IAVI) for mobile computing systems. In IAVI, we define an absolute validity interval (AVI), for each data item based on its dynamic property such as the update interval. A mobile client can verif y the validity of a cached item by comparing the last update rime and its A VI. A cached item is invalidated if the current rime is greater than the la st update time plus its AVI. With this self-invalidation mechanism, the IAV I scheme uses the invalidation report to inform the mobile clients about ch anges in AVls rather than the update event of the data items. As a result, the size of the invalidation report can be reduced significantly. Through e xtensive simulation experiments, we have found that the performance of the IVAI scheme is significantly better than other methods such as bit sequence and timestamp.