LINC and the Internet
A down and dirty guide on how to view a LINCed report in its entirety from anywhere on the Internet, with any browser you choose.
As the LINC community becomes more Internet-aware, Unisys is responding by making it easier to put LINC systems on the Internet. With LDA III 2.3, you can directly generate a system to LINC 16.3 on an NT platform and very easily deploy that system, or parts of it, to Web browsers using Web Agent (see Figure 1). While Web Agent may eventually allow access to ROC (Report Output Control) to view the outputs, it likely will be limited to one screen at a time – cumbersome at best. Further, there might not be character highlighting such as special fonts and colors.
Therefore, we established an objective to provide a way to view a report’s output in its entirety (including highlights) with any browser from anywhere on the Internet; once in a browser, it could be printed on that PC’s printer (see Figure 2). This was to be a proof-of-concept and something members of the LINC community could build upon for their own requirements. Sounds simple enough.
Unfortunately, there were some hurdles to overcome. As you may already know, NT LINC applications use Oracle as the database and Microsoft provides free ODBC drivers for Oracle databases. Thus, all the pieces are there, we just had to assemble them.
Steps to the Objective
The first major step was to deploy the SAMPLE system (supplied with LDA) to the Web, which involved quite a few sub-tasks. A few words of wisdom are in order here. You should deploy the SAMPLE system before trying to deploy any of your own systems. This will help you establish your own procedures and checklists. SAMPLE deploy cleanly and has GUI screens built in. Your own systems might not deploy successfully, and you may face a number of specification migration issues. After running the SAMPLE system from a Web browser to enter some data, we used its report menu to produce some report outputs.
The next major step was to decode the output from the reports. The first trick here is to find out where the reports go. You can save some time by visiting the "put stuff" link. Although they are "flat" files, they are readable only by programs and weirdos. We actually had to write some software to help hack this stuff. Adding a decrypter from the CIA to your technical pioneering team would be wise, but that is just one of many solutions. We also wrote a very small test report to help pinpoint some format translation issues. This led us to having to add to the Output Control codes file. Once the format and contents of the ROC files was sufficiently understood (we are still learning), we developed an ASP to read the flat file and convert it to standard HTML. The first cut of this ASP had the ROC file name in hardcode – an elegant solution it is not.
Clearly we needed to set parameters for the ROC file name. This took us to the next major task of finding out from ROC’s database what files are available. We thought doing this with ODBC would be extremely simple, but were we ever wrong. Using MS Excel, we were able to see the sample databases that Oracle installs, but we were not able to connect to ROC16. Be very careful here. You really do not want non-LINC applications to be able to update the LINC databases since there are special tables and data items that must be kept in sync, or your LINC application system will fall over dead!
Finally, having a mechanism to retrieve a list of ROC report output file names along with related information, we were able to build a second ASP to provide a "menu" of reports available. Remember that the browser and user never see the ASP code that reads LINC databases; they only see the HTML built by the ASP. A good production implementation of this ASP would be to make the ROC viewer an "ASP application" and open the ODBC connection at the application level. That would minimize the overhead of open/close.
Face it. E-business, e-commerce, zero-latency ... all of the current buzz words are in the writing on the wall. Update your skills so you can make your company’s systems open and available to anyone with a browser on the Internet or intranet or extranet. Technology from the LINC suite can do it, can you?
About the Author: Phil Kauffman is a director with the Information Exchange Group, Inc. for the Chicago area. He can be reached at (630) 759-7162, or via e-mail at firstname.lastname@example.org.