Negotiating the divide between Green Screen and GUI
IBM i customers face a familiar dilemma when weighing traditional green screens against graphical user interfaces (GUIs): or browser. They have considerable resources committed to the older protocol, yet today's end users are likely more interested in the offerings of the modern alternative. What IBM i shops must realize, however, is that making a yes or no distinction between the two is a false proposition. Each has their own pros and cons that must be acknowledged and leveraged in different scenarios.
Delineating the differences
Green screens are the incumbent technology, hearkening all the way back to the days of IBM 3270 terminals. They've since carried on through the 5250, AS/400 and now IBM i for Power Systems. Despite their declining popularity among the latest generation of programmers, green screens can still be counted on for "quick and dirty" command-line tasks, according to iPro Developer. Additionally, it's worth noting that a number of companies still have too many of their stock applications tied up in green screens to abandon the command-line model completely. These transaction based systems require speed and accuracy to capture the data and not necessarily GUI. Think of waiting in line at a hotel and then ask the receptionist to show you the screen behind the process. Most are still running Green screen on IBM i.
That's not to say there haven't been drifting loyalties, however. A number of today's users deride green screens as fossils, expressing a longing for more aesthetically pleasing and familiar navigation tools. Even if these views are entirely subjective, catering to the demands of end users and upper management is always one of the core obligations of application architects.
Many of the strengths associated with browser-based/GUI utilities are then defined by green screen's shortcomings. Learning curves are typically much smoother for new users, multitasking is often much easier and apps are effectively made into device-agnostic web pages. Drop down menus, tabs and hot keys also mesh with familiar modern workflows. Yet there remains a lack of control and an uptick in compute resources required to support GUI functionality. As a result, IBM has been slow to evolve its operating system interface accordingly.
For those interested in embracing the future without abandoning their past, solutions are available. There are a number of conversion utilities out there which form green screen emulators, modernizing the interface via lightweight, browser-based installations. Moving forward, however, it may be best to begin new application development processes from a GUI foundation. Although IBM i's reliability and ubiquity have helped extend the viability of green screens, GUI formats are likely better suited to the sensibilities of the user base being served.
I would argue that going directly to Browser from 5250 should be the path for anyone still running green screen. Who wants to install a GUI on every desktop? Browser lend themselves to mobile computing and other future technologies. I do not recommend GUI.