Virtually split approach for mobile computing environments

Limitation of bandwidth and frequent disconnections are main characteristics of mobile computing environments. in this paper, we propose a concurrency control scheme for mobile computing environments which can reduce the effects of frequent disconnections and limitation of bandwidth. Our primary goal is to enhance the performance of the optimistic concurrency control for mobile computing environments by reducing abort rates, unnecessary operations and validation time. In our scheme, each mobile host sends a write set to a fixed host during the execution phase. When the fixed host receives the write set, it performs validation test with the write set. After this prevalidation, if there is no conflict with other transactions, pre-validated data items have to be locked. The pre-validated data items don't need to be revalidated in the validation phase. In our approach, each transaction is virtually split when the transaction performs a write operation. in this paper, we also present the result of a simulation that compares our schemes with the optimistic concurrency control with time-stamp history and the pessimistic concurrency control. The result shows that our scheme outperforms the others.