introductiontoinationsystems1.1

1、liu hiss, wuhan university uftp is the primary means of getting files from the remote host on the internetuwhen the file is sent from client to a remote host, known as the “file upload” (upload); otherwise, known as the file download (download).utransferred files can be text files, executable files,

2、 sound files, image files, data compression （压缩）files.utelnet is a network protocol(xie yi) used on the internet or local area networks to provide a bidirectional（双向的） interactive communications facility via a terminal （终端机）connection.uuser logs on to another host via a virtual terminal connection a

3、nd enjoys the resources and services provided by the host（主机）.ask for the resourceprovide the resourcethe browser is considered as a client.the site that supplies the information is considered as a server. umicrosoft internet information server(iis)uapache serveruibm websphere服务器微软互联网信息服务器(iis)apach

4、e服务器ibm websphereprotocol:/name of machine name of resource协议协议:/ /名字的机器名字的机器名称的资源名称的资源)http:/ transfer protocol a communication protoclhow do i get this resource name of the machine hosting the resourcewhat server has this resource? name of the resource addressed by the url what resource specifically?udisadvantage: fat clientsstep 1: a client ask for a dynamic pagestep 2: web server look for the page and send it to application server to perform some tasksstep3: the application server accomplish these tasks and form a new page to return