RPG Virtual Machine Opens Windows to New Applications

At last count, more than 30,000 vertical market business applications have been written for IBM Corp.'s (www.ibm.com) AS/400 midrange computing platform. Now, a new tool lets organizations recompile existing AS/400 applications for Microsoft Corp.'s (www.microsoft.com) Windows 2000. The Cross400T compiler and development environment from CrossWorks Inc. (www.cross-works.com) has been available for use with Windows NT, but in early March the company announced Cross400T now supported Windows 2000, as well.

Cross400T is not an integration tool or interoperability gateway, such as Microsoft's SNA Server product, explains David Schindler, vice president of marketing at CrossWorks. Thus, even when Microsoft releases its next-generation SNA Server -- code-named Babylon -- there will still be a distinct role for a code recompiler.

In fact, Babylon will likely sound the death knell for competitive client-to-host gateway solutions on the Windows 2000 platform, says Rob Enderle, senior analyst at Giga Information Group Inc. (www.gigaweb.com). The SNA Server will be revamped to function as a general-purpose interoperability connector to heterogeneous mainframe, AS/400, and Unix hosts, as well as to the applications that reside on them. Since Babylon will use Microsoft's Windows DNA 2000 framework, the next-generation host-connectivity product is expected to help developers build distributed applications without rewriting code or following today's common practice of wrapping code in COM or CORBA objects.

Cross400T can obviate the need for an integration component or interoperability gateway by letting administrators recompile existing AS/400 applications written in RPG on Windows NT, Windows 2000, SCO Unix, AIX, HP-UX, and Solaris platforms.

This opens up a range of rich applications to Windows shops. To date, a number of vendors have successfully marketed a plethora of industry-specific applications for the AS/400, including applications for markets that range in diversity from metal pressing shops to wineries. While many ISVs may want to port their applications to the newer and sexier client/server platforms, they are ultimately deterred from doing so by the effort that such a porting necessarily involves, CrossWorks' Schindler says.

"Most of these ISVs are not looking at giving up the AS/400 in terms of marketing to it, they just want to market to the Windows NT and 2000 environments as well -- ideally with a single set of source code," Schindler explains. "But chances are, if you're talking a typical application, you're talking 500,000 to 1 million lines of code. You're not talking about a small effort for these vendors," he adds.

Cross400T works a lot like a Java virtual machine, says Schindler says, except that RPG code compiled on Cross400T running on Windows NT won't be executable on Solaris -- or other platforms, for that matter -- and vice versa. For its part, the Cross400T is composed of an RPG compiler and an RPG virtual machine that creates objects from native AS/400 RPG that can then be executed by the Cross400T's platform-specific virtual machine component.

In the final analysis, Schindler says that Cross400T is a great solution for ISVs or other companies looking to port AS/400 applications to a variety of Windows or Unix platforms with very little custom-coding.

"Most of these companies are looking very actively to figure out a way to market their apps to the Windows NT/2000 world, but they're running up against the problem that they have either to rewrite or recompile," he states. "They don't want to abandon these applications, because most of them have been around for a while and are very functional and feature-rich."

PullQuote: Cross400T can obviate the need for an integration component or interoperability gateway by letting administrators recompile existing AS/400 applications written in RPG on Windows NT, Windows 2000, SCO Unix, AIX, HP-UX, and Solaris platforms.