Have you ever thought about the different shades of green (screen) modernization?
Over the last several year or even more than a decade their have been multiple approaches on how to modernize character-based terminal screens (3270, 5250, 9750 and other terminal protocols) providing access to mainframe or legacy applications. Terms like Web-to-host, Screen-scraping, Web-enablement or others have been invented around this issue of making old-looking screens more modern. Several people I have talked to over the last several years have mixed experience with those kind of products or even have developed their own tools to address this issue – there is pretty much no grew-zone experience, the people either like it or hate it. But let us do a reset of our mindset for now and let us have a neutral look on where we are today with these green screen modernization technologies.
Before considering this technology you may have to make a decision what kind of user or business problem you need to address, what kind of architecture you want to follow and what will be the effort of achieving this.
If you are not planning to redevelop or change your application code then the following options are available.
- Use your terminal emulation capabilities to use the green screens out of a Web browser-based environment with basic level “beautification”, i.e. different fonts, colors, function keys. It is pretty much a one-to-one mapping of a screen to a little bit nicer screen.
- Stay with the green screen, but smartly wrap it to improve usability and accessibility, e.g. running in a Web browser enriched with HTML and Javascript capabilities. This transformation can be simple from modernizing just one screen to complex screen aggregations, where one Web page manages multiple green screen sessions in the background.
- Functionally wrap the green screen and expose the data and business logic as services (Web Services, REST, Java or .NET) and integrate these services into Web or desktop applications.
You should not cut out these capabilities from your portfolio of solving a problem, as many of them can provide a very good ROI by addressing specific business requirements rapidly and without major impact to your system (non-invasive).
In the next series I am going to explain the pros and cons of these green screen modernization approaches.
