Mobile computers such as notebooks, subnotebooks, and palmtops require low weight, low power consumption, and good interactive performance. These requirements impose many challenges on architectures and operating systems. This paper investigates three alternative storage devices for mobile computers: magnetic hard disks, ash memory disk emulators, and ash memory cards. We have used hardware measurements and trace-driven simulation to evaluate each of the alternative storage devices and their related design strategies. Hardware measurements on an HP OmniBook 300 highlight di erences in the performance of the three devices as used on the Omnibook, especially the poor performance of version 2.00 of the Microsoft Flash File System 11] when accessing large les. The traces used in our study came from di erent environments, including mobile computers (Macintosh PowerBooks) and desktop computers (running Windows or HPUX), as well as synthetic workloads. Our simulation study shows that ash mem...
Fred Douglis, Ramón Cáceres, M. Fran