Research And Implementation On Transparent Computing System Based On Hierarchical Cache

As a new model of network computing based on C/S architecture, Transparent computing can effectively reduce the using and maintaining cost of computer systems, what's more, its clients'performance is close to some personal computers with the same hardware configurations, consequently widely applied in so many places, such as school, internet bar, government and so on. However, with growing in number of clients gradually, their I/O performance will decline rapidly, which will seriously limit the popularization of transparent computing system. It is a hot research topic to study how to improve I/O performance in certain application environment of transparent computing, whose goal is to fit for super transparent computing system.First of all, the paper studies and analyzes the technique characteristics of all transparent computing models, and implements a remote startup protocol based on transparent computing models, which makes use of the skills of pxe long-distance startup in Intel to load operating system's long-distance inducting and programs dynamically, at the same time, then proposes an effective implementation framework of a transparent computing system based on hierarchical cache. The framework implements local virtual disks based on block mode in clients by drivers of SCSI ports or tiny ports, providing a storage view similar to local physics disks to clients, and designs a simplified similar ISCSI communication protocol, which redirects the I/O visiting requests for disks in clients to servers using the method of network transparent computing and accomplishes corresponding I/O tasks.Secondly, for the sake of improving response performance of I/O request from transparent computing systems, after studying and analyzing the visiting model of I/O request for servers in transparent computing, the paper designs a two-level cache structure, which reads and writes caches in client and server to improve I/O performance. At the same time, in order to improve the cache hit ratio according to the given environment of transparent computing, the paper implements a modified LRU replacement algorithm called LRU-AFS based on the count threshold of data accessing times.In the end, the paper designs and implements a transparent computing system based on hierarchical cache based on the above research and tests its performance. Test results show that, with growing in number of clients in LAN, HCTS can better improve and enhance the client I/O performance compared to general TS, reducing the network traffic dramatically, shortening the boot time significantly and increasing the random read-write throughput of clients effectively.