Background

Web technology has proliferated in the computer industry at such a spectacular pace that one can ignore it only at one's peril. Unlike some previous fads in the computer industry, web technology almost from day one was being used to perform real and useful work. From electronic commerce to document distribution to package tracking, the list of applications available on the "Web" and "intranets" is astounding when one considers that the technology first became available in 1993.

It is easy to see the appeal of web technology. Web browsers provide an easy-to-use but powerful means of accessing data. Control of web applications is centralized and relatively independent of the actual browsers being used. Web technology makes it easy to combine images and text and to produce input forms. Hypertext links provide an easy way for inexperienced users to find their way around an application with little or no training while allowing experienced users to go directly to the part of an application they are interested in.

All technologies, however, have their weaknesses and web technology's weakness is its limited access to existing applications and databases. Currently available solutions to this problem generally involve Common Gateway Interface (CGI) which has many problems with security and maintainability, especially in accessing legacy databases. To make matters worse, third party tools which inherit these shortcomings tend to take an SQL-centric view of databases which adds more overhead, limitations, and debugging and maintenance headaches when attempting to provide access to Model 204 data and applications.

Janus Web Server: Access to Model 204 Data and Applications

Janus Web Server was written by Sirius Software to solve these problems and to make it as easy to provide access to Model 204 data and applications from a web browser as it is from a 3270. The Janus Web Server allows Model 204 to act as a web server on a TCP/IP network, serving up plain text, html, graphics and other binary data directly from Model 204 files combined with database data into sophisticated and dynamic web pages. Existing applications can often be re-written for web access with one-tenth or less of the code required for the equivalent 3270 applications. This is because many of the navigation and end-user interface issues that must be dealt with by a 3270 application are handled by web browsers. Furthermore, the existing Model 204 security structures -- userids, passwords, file, field and record security -- can be used as needed, while non-secure data can be served to web browsers without any protection. For maximum security, the addition of Janus Network Security makes Janus Web Server fully compliant with the Secure Socket Layer (SSL) protocol, providing end-to-end encryption of logon ids, passwords and data.

Janus Web Server does not require the use of any other web servers - Model 204 itself is the web server. This means no new interdependencies between Model 204 and other vendor products, no need to maintain applications as a complex set of parameters and programs in two or more environments, no need to leave non-secure back doors into Model 204 to facilitate web server access, and no need to maintain multiple sets of userids and passwords for a web server and Model 204.

The Janus Web Server supports the full http protocol, allowing it to be a complete corporate web server and also permitting web applications to benefit from Model 204's speed, security, scalability and integrated programming language.

Integrated With User Language

The full power of User Language is immediately available to a Janus Web Server site. With Janus Web Server, User Language can send data to a web browser with simple PRINT statements that contain either HTML or ordinary text. Output from Model 204 commands can be routed to a web browser with no programming at all. HTML documents generated by client based tools can also be served by Model 204 with automatic substitution into dynamic parts of these documents from data that is set in GTBL by User Language. A set of $functions is provided that make it possible to retrieve information about a browser request and to completely control the data sent back to the browser. These $functions can return the values of the data entered on an HTML form, the actual browser being used, the URL used to initiate the request, and more.

Janus Web Server's ability to serve static HTML, image, and audio data from Model 204 procedures makes it possible to maintain both the form that initiates an application request and the application itself in the same procedure file. Static data can also be kept on other servers and simply be pointed to by Model 204 as needed. Janus Web Server "redirects" make it possible to move data to and from other web servers without changing existing hyper-text links to that data. Finally, as with all Sirius Software products, Janus Web Server is written in assembler and is highly efficient.

Janus Network Security

One of the classic shortcomings of client/server and web technologies is security. Since client/server and web connections typically operate over non-secure networks, all data for these connections is vulnerable to eavesdropping. Passwords and other sensitive data in client/server and web connections can easily be captured by unauthorized third parties and then used to further compromise security.

To solve this problem, Netscape Communication Corp. with help from RSA data Security Inc. developed the Secure Sockets Layer (SSL) protocol to enable secure communications over non-secure networks. The SSL protocol encrypts data in such a way that an unauthorized third party cannot possibly decrypt it and, thus, compromise security.

The Janus Network Security option implements the SSL protocol inside Model 204 making it possible for Model 204 to participate in secure client/server and web applications. The Janus Network Security option provides strong encryption support for Janus Web Server.

Janus Web Server Legacy Support

The Janus Web Server Legacy makes it possible for end-users to access existing User Language 3270 applications from a web browser without any code changes to the User Language applications. Standard web navigation techniques such as hyper-text links can be used to access application subsystems (APSY's) or even specific screens in an application subsystem. Userid and passwords for the applications are received from the web browser, eliminating the need for end-users to enter userids and passwords multiple times.

For Model 204 sites with hundreds of thousands or even millions of lines of User Language code, it is simply not practical to rewrite all legacy 3270 applications as web applications, even given the simplifications made possible by the web paradigm. While key applications might certainly be rewritten to take advantage of the web paradigm, hundreds of others must be left as 3270 applications. Even for sites that intend to rework all applications as web applications, there will be a long period of time where converted web applications will have to co-exist with legacy 3270 applications. In this co-existence situation, Janus Web Server Legacy Support eliminates the need to have end users switch back and forth between web browsers and 3270 sessions on their workstations.

Summary

Janus Web Server makes it possible to bring Model 204 into full participation in a web environment with all its benefits to end-users. Janus Network Security provides the security needed to enable commercial-strength web applications to be written in Model 204 User Language. For situations where rewriting existing applications in the web paradigm is impractical, Janus Web Server Legacy support makes it possible to integrate legacy 3270 applications into the web environment.

Janus Web Server requires Janus TCP/IP Base and will work with all supported versionf of M204 on MVS and VM operating systems. Janus TCP/IP Base provides support for IBM's, Interlink's (TCPAccess) and Gulf Computer's (Knet) mainframe TCP/IP packages.