No abstract

Kimberley enables rapid software provisioning of fixed infrastructure for transient use by a mobile device. It uses virtual machine (VM) technology, but avoids the performance challenges of running VMs on resource-poor mobile devices. VM execution only occurs in the infrastructure and never on the mobile device; however, the device may transport and interpret parts of VM state. Kimberley decomposes VM state into a widely-available base VM and a much smaller private VM overlay. The base is downloaded in advance; the overlay is delivered on demand from the mobile device or under its control from a public web site. We have built a prototype of Kimberley, and our experiments confirm the feasibility of this approach.

We report on the design, implementation, and evaluation of a system called Cedar that enables mobile database access with good performance over low-bandwidth networks. This is accomplished without degrading consistency. Cedar exploits the disk storage and processing power of a mobile client to compensate for weak connectivity. Its central organizing principle is that even a stale client replica can be used to reduce data transmission volume from a database server. The reduction is achieved by using content addressable storage to discover and elide commonality between client and server results. This organizing principle allows Cedar to use an optimistic approach to solving the difficult problem of database replica control. For laptop-class clients, our experiments show that Cedar improves the throughput of read-write workloads by 39% to as much as 224% while reducing response time by 28% to as much as 79%.