Computer Science Department
School of Computer Science, Carnegie Mellon University
Safe Transient Use of Local Storage
Stephen Smaldone*, Jan Harkes,
This paper investigates the transient use of free local storage for improving performance in VM-based mobile computing systems. Many such systems boot from a portable storage device to create a "zero-install" environment on a computer that is borrowed for temporary use. Unfortunately, consumer-grade portable storage devices are optimized for capacity and cost rather than performance, which has been shown to be a critical factor in user experience on VM-based systems. We propose a zero-install solution called TransPart that uses the higher-performing local storage of borrowed hardware for performance-critical operations, yet preserves the integrity and privacy of data on that local storage. Our solution constructs a virtual storage device on demand by safely borrowing free disk blocks from the host's storage. We present the design, implementation, and evaluation of a TransPart prototype that requires no modifications to the software or hardware of a borrowed computer. Experimental results confirm that TransPart offers low overheads and startup cost, while improving user experience. We also suggest potential uses of the ideas underlying TransPart in other VM-based contexts.