基于瘦客户计算的嵌入式系统可扩展结构.docVIP

基于瘦客户计算的嵌入式系统可扩展结构 //.paper.edu.cn - 1 - An Extensible Embedded System Architecture based on Client-Server Computing1 Wu Yuechuan, Zhang Youhui, Tian Tao Tao TianDepartment of Computer Science and TechnologyTsinghua University, Beijing, P.R.China (100084) Abstract This paper presents an extensible architecture for embedded systems, which borrows some features from the client-server computing and Common Interface Specification for Conditional Access (CA) of Digital Video Broadcasting Decoder Applications to endow the stand-alone embedded systems with new functions in a compact mode. Compared with the traditional CA module that uses PCMCIA standard, in our solution, USB interfaces and IP-over-USB are used to connect the original system to one or more extensible nodes with new functions to construct a “network”. Through the high-speed USB network, the existing client-server computing mode can be ported to embedded systems. That is, the extensible node acts as the server that deals with requests from the client—the original system. And functions of original embedded systems can be extended or upgraded easily if new nodes are attached. We believe this solution will bring forward new applications for some existing systems. For example, if Digital TV (DTV) owns this feature to interact with extensible nodes, DTV itself can act as a graphic terminal and provide new applications, including games and programs, to users only if the attached node can provide such functions. And users can upgrade or select the nodes as they prefer. In this paper, a system model for the extension is introduced as well as a demo prototype implementation. In the prototype, the USB-based Ethernet is simulated and the TCP/IP protocol can be used directly. Keywords: embedded system, client-server computing, USB 1. Introduction The main objective of the traditional embedded systems is to find a good architecture to perform one single, given task [1]. Now new embedded syst