Mei-Ling Chiang, Paul C.H. Lee#, Shih-Yueh Lo and Ruei-Chuan Chang#
Department of Computer and Information Science
National Chiao Tung University,
Hsinchu, Taiwan 300, R.O.C.
# Institute of Information Science
Academia Sinica, Taipei, R.O.C.
PDAs (Personal Digital Assistants) are resource-limited systems that cannot directly employ conventional system software. In this paper, a new memory-based object server, ROSS, for PDAs is presented. An enhanced buddy system and application-specific on-line object compression are employed to increase memory utilization. To keep data consistent, transaction management is also included in the server. Performance evaluations show that ROSS meets PDA requirements and performs well in PDA applications. The enhanced buddy system effectively reduces the internal fragmentation incurred in the basic buddy system and outperforms the conventional block-based allocation system in memory utilization. ROSS requires only 81.31% of the storage space required by Newton for the PDA Names application.
Keywords: PDA, buddy system, compression, transaction processing, mobile computing
Received May 30, 1996; revised May 21, 1997.
Communicated by Ming-Tat Ko.
* This work was supported in part by the Computer & Communication Research Lab., Industrial Technology Research Institute, R.O.C.