Both bibliographic data and PDF files can be accessed free until December 2005. Copyright reserved. Table of Contents i-ii Message from the IPSJ president iii-iv Editorial board for 2005 Volume 1 (2005) 15-25 Wireless/Mobile Networks Spurious Timeout Detection Algorithm for Mobile Communication with Delay Jitter Motoharu Miyake, Hiroshi Inamura, Osamu Takahashi A spurious timeout (STO) leads to an unnecessary go-back-N retransmission and throughput degradation, which negatively impacts the user's TCP performance. In this paper, we propose an STO detection and congestion window control algorithm based on the first acknowledgment following an RTO monitoring event for suppressing both the unnecessary retransmission and throughput degradation. This method strongly supports the enhancement of existing mobile communications systems because it does not require additional information or receiver modification. 1-14 Parallel and Distributed Processing Technology RX-NAS: A Scalable, Reliable Clustered NAS System Yoshiko Yasuda, Shinichi Kawamoto, Atsushi Ebata, Jun Okitsu, Tatsuo Higuchi, Naoki Hamanaka RX-NAS (Replicated eXpandable Network-Attached Storage), a scalable, reliable clustered NAS system designed for entry-level NAS, has been developed. RX-NAS is based on X-NAS, which is a simple clustered NAS architecture for entry-level NAS, and improves the reliability of X-NAS by adding new sets of X-NASs to the original one. The core feature of RX-NAS, namely on-line replication, replicates original file objects to new sets of X-NASs for each file block in real-time without changing clients' environments. RX-NAS has other key features for maintaining the manageability of entry-level NAS; namely, new synchronization and resynchronization functions can easily replicate original files and directories to other X-NAS systems completely or partially without changing clients' environments. In addition, its health-check function can eliminate a limitation on the configuration of RX-NAS and detect and report errors that occur in the RX-NAS system. To validate the RX-NAS concept, an RX-NAS prototype was designed and tested according to the NFSv3 implementation. These tests show that the RX-NAS improves system reliability while maintaining 80% of the throughput of X-NAS.