Big Iron (Mainframes) and the World of Tomorrow
There was an article in CNET yesterday espousing the need for developers to pick up mainframe development, and schools reinstating their mainframe classes. While I don't think anyone should waste their time learning about a mostly dead technology, it makes sense to learn from the applications developed on mainframes and take the lessons with a grain of salt.
Right now I am working on converting a legacy mainframe application that was implemented in the 1970's into a web application. The real issues are stemming from the current business process with that mainframe. The database, probably some RDBMS variant, is normalized in such a way that it makes enough sense to keep that structure rather than try to re-invent the wheel. What has been suprising is that it also makes sense to maintain most of the data presentation layer.
The people who use the current system get a ton of data from a very small amount of screen real-estate. The mainframe systems were usually text based, and limited in the number of characters that could be stored in a field, and therefore displayed. Much of the business process that resulted from these limitations has evolved around using codes and cheat sheets to figure out what the codes mean. This also has the effect of shielding somewhat sensitive information from outsiders and customers. The use of codes as a shorthand for more detailed information also has the effect of being able to transfer a large amount of knowledge in a very short time for experienced users. Similar to the way we use compression to zip a text-file into a much smaller file for translation later. When a user inputs the code, they are compressing their idea into a few characters that the user on the other end can understand.
I have been more fortunate than most, because I have access to one of the original architects of the system, and I believe that having an understanding of the business environment and the system architecture is more important than knowing the actual code. Most people looking to hire individuals who understand the mainframe are really looking for people to dis-assemble their applications and rebuild them as web applications.
The article in CNET further implies that mainframes still sport some advantages over server based applications. That may be true to a degree for deployed desktop applications, but maiframes have no advantage when it comes to web applications. Still, people who know COBOL, FORTRAN, and other low level languages can command a premium for their technical knowledge in the few shops who feel that maintaining these mainframe applications and hardware are better for some reason than replacing them, but it is only a matter of time until these shops agree that paying an ever increasing amount for maintenance and upgrades is more expensive than bringing someone onboard to convert the application to the web. Therefore I see no future in the mainframe, however some great applications were developed for them, and the applications that are still running on them were probably more robust than average.
Much of the methodology I tend to follow when constructing a database or organizing code were implemented for the first time on big iron, so I actually feel priviliged to be able to work with it. Its almost like looking into a time machine where you can see and feel the environment of the past which, even though it may seem the same, is vastly different than the business climate today.