Originally introduced by Netscape Communications,___(66)___ are a general mechanism which HTTP Server side applications, such as CGI (67) , can use to both store and retrieve information on the HTTP ___(68)___ side of the connection. Basically, Cookies can be used to compensate for the ___(69)___ nature of HTTP. The addition of a simple, persistent, client-side state significantly extends the capabilities of WWW-based ___(70)___ .

A．Browsers　　　

B．Cookies

C． Connections　

D．Scripts

可扩展性、高可用性、并行性都是集群系统的基本属性