The Research Of Embedded Web Server Supporting Software Migrating On Demand

With the rapid development of information technology and constant improvement of hardware level, it shows a tendency that the quantity of mobile device increases fast. Mobile phone and personal digital assistant (PDA) play a leading role in the market nowadays. On the other hand, people have higher requirement for acquiring information in time. More and more people hope to obtain information whenever and wherever possible, and have new requirements for the type of information, such as the wireless e-commerce. But e-commerce technology requires the enormous platform of system application, huge code data, high-speed operation tempo and surprising network bandwidth.Compared with PC with higher performance, handheld mobile devices have more limited calculation environments: CPU with weaker computing capability, less memory, the limited power consumption, little display result and different input equipment; Compared with steady wired network, the wireless network is likewise a more limited communication environment: smaller bandwidth, longer delay and more unstable connection. It makes some enormous application program, such as wireless e-commerce, unable to run on handheld mobile devices. It restrains the popularity of new application in wireless mobile computing environment undoubtedly.Embedded web server is one of the applications of embedded Internet technology. Because we need to place web server in the embedded system, we must realize thin web server on the influence of limit of resource of embedded system. There has been some research and applications of embedded web server nowadays, and they mostly realize functions as follows: The embedded devices connect to Internet through embedded web server, and users can use abundant GUI to manage, configure, and control embedded devices. The embedded devices can transmit their run-time state and parameter to the browser at client. The research of embedded devices communicating with normal web server through embedded web server is still less.Aiming at the problem of mobile devices of limited resource unable to load and operate bigger software, this paper researches relevant supporting mechanisms of embedded web server in the system of software migrating on demand. The system of software migrating on demand means that application program adopts the design method of module, and it is formed by some small modules called"piece". When users need, these small pieces are loaded to mobile devices separately. The client system adopts the network structure of P2P. As a peer in P2P network, mobile devices not only can get piece they need from other mobile devices as the client, but also can offer pieces they cache to other mobile devices as a server.The main work of this paper is as follows:1) Have defined the concept of piece, and introduced a new design method of application program. An intact application program is formed by several pieces which have unique function, and a piece is formed by described file and code segment. We can discern piece by described file, and carry out the function of piece by code segment. Mobile devices can load piece to carry out according to their need, so can obtain the function that they need.2) Have explained the whole architecture of the system of software migrating on demand, and its component part such as intelligent proxy server. Have described the function and pole of intelligent proxy server in the system. And have analyzed the characteristic and the function of each component module of intelligent proxy server.3) Have further studied the network structure of the client system, and put forward the design method combining P2P and grid. The advantage of P2P and grid is utilized fully. It makes mobile device obtain piece from other peers through inquiring high-speed service grid. It not only can improve the efficiency of execution but also can reduce the burden of intelligent proxy server, and makes the whole system steady, high-efficient and convenient.4) Have designed an embedded web server supporting software migrating on demand, and have introduced each module of its component part. The main module, SMOD, is especially designed in detail, and its function is analyzed deeply.