The Modernization Face-Off - RPG vs. PHP
By: David Russo
For years now there has been a lot of debate surrounding how businesses with System i servers should modernize their legacy applications. In the past, the main options outside of native RPG were Java or leaving the System i platform. Now, a new option has emerged for the System i community to consider. This new option is an open source scripting language called PHP. So, how does this new open source scripting language face up against the proven option of RPG on the System i?
After some analysis, we found that PHP is a capable scripting language, but for System i shops looking to develop business-critical browser applications, it may not be the best choice. The main benefit PHP brings is that we can now adopt a number of existing PHP applications, such as forums and wiki's, to the i. However, for those shops looking to build Web interfaces to their DB2 data and tap into existing RPG systems, there is little business reason to jump into PHP. There are many complications involved in migrating to a new language and technology, not the least of which is the time and cost investment in retraining existing System i developers or in finding and recruiting new PHP developers. Migrating development to a new language is often a drastic shift in the operations of the IT department which can take years to complete.
If PHP had arrived on the System i 10 years ago, the time and cost investment might have been a good trade off for the new capability that PHP would have provided back then. Today, this is not the case. There is nothing that can be done in PHP that cannot also be done natively on the System i platform using the modern ILE form of the RPG language. Conversely, there are many features and capabilities inherent to RPG which are not available in PHP, such as RPG's ability to access record-level data directly without using drivers or other APIs.
Another advantage of RPG is that it is the established language of the System i platform. In most cases, System i shops are RPG shops. RPG is (and has been for decades) an easy to use, fast, and reliable language for creating business applications. Although the number of PHP developers in the overall IT marketplace greatly exceeds the number of RPG developers, these PHP developers often do not have the years of business experience and insight common among RPG developers. It goes without saying that RPG shops get to the Web faster and with less training using RPG than with PHP.
Furthermore, RPG has direct access to all System i functionality. Using RPG, developers have easy access to all of the great integrated features of the System i platform. RPG programs can easily call (and be called by) any other System i program, written in any language available on the system. RPG programs also have direct access to any i5/OS command or system API.
RPG is an excellent language for business applications. No other language around makes it as easy to write great business applications as RPG does. Database access is seamless and utterly reliable. Functions for dealing with dates and currency amounts are built right in. In fact, the only drawback to RPG historically, had been its inability to interoperate with graphical display technologies. This restriction has been removed some time ago, and today's ILE RPG IV language retains the characteristics which make it a great business language, and adds the capability of interacting seamlessly with a Web server and Web browser to create modern, graphical user interfaces.