Accessing X Applications over the World-Wide Web Arno Puder and Siddharth Desai San Francisco State University Computer Science Department 1600 Holloway Avenue San Francisco, CA 94132 {arno|sgd1977}@sfsu.edu Abstract. The X Protocol, an asynchronous network protocol, was de- veloped at MIT amid the need to provide a network transparent graphical user interface primarily for the UNIX Operating System. Current exam- ples of Open Source implementations of the X server, require specific software to be downloaded and installed on the end-user’s workstation. To avoid this and other issues involved in the conventional X setup, this paper proposes a new solution by defining a protocol bridge that trans- lates the conventional X Protocol to an HTTP-based one. This approach makes an X application accessible from any web browser. With the goal of leveraging the enormous browser install base, the web-based X server supports multiple web browsers and has been tested to support a number of X clients. 1 Motivation The staggering rate at which the World-Wide Web has grown over the last decade is evidenced by the number of websites that are accessible over the Internet today. Web browsers, the end-user applications that connect to these websites and display content have also evolved at an impressive rate. Originally based on a document-centric architecture, where a web browser would only display static HTML pages, much work has been done to define extensions that allow for operational interactions. Thus web browsers have generic interfaces for web- based applications. Although the most popular browsers are freely available and readily down- loadable from the Internet, most operating systems today bundle a web browser. As a result, the install base of web browsers has dramatically increased. This has been leveraged by companies that do business online and software providers who have migrated their native client interfaces and made them web-based. The obvious technical benefit is that with all prerequisite software already installed, installation and configuration for such web-based applications is dramatically reduced or even eliminated altogether. In this paper we introduce a technique that allows to access X applications – based on MIT’s X Protocol – through a web browser. This will make X appli- cations that traditionally require an X server to be installed, accessible in a web