Resource Management Holy Grail Includes An Opal

By Richard Hoffman Corporate IS managers frequently face requests to expand access to mission-critical host session applications. "Web-enabling" existing applications has become a kind of IS holy grail: Everybody wants it, but the chase is exhausting and empty pockets and a lot of sweat may be all you find at the end. The costs of redesigning and retesting functional changes to critical host-based applications may be greater than those of rewriting the applications.

Infresco Corp.'s Opal version 2.1 aims to solve these problems by providing managers with a powerful (but flexible) software product for revitalizing and reusing existing code or database resources, making those resources more widely available. The Opal run-time application development environment repurposes and visually updates existing host applications with powerful G UI tools, offering "new" applications to users on a variety of workstations via standalone or Web browser-based methods.

Ideally, Opal makes an IS manager look like a wizard by reducing redevelopment time and costs dramatically over the alternative of database rewrites or migration and object-encapsulation of critical code modules.

With an Opal 2.1 beta copy, I screen-scraped existing host-based applications, created more functional and attractive user interfaces, added multimedia to those applications, and connected directly to multiple data sources. I also combined several existing applications and data sources into a single Opal application. I had the option of running the resulting "virtual application" directly as an executable through the Opal Player or converting it to an Internet browser-based application.

While I found Opal easy to use, a nd the included Assistants generally well written, this is not a product for nonprogrammers--despite documentation claims that it "does not require you to have prior programming experience." If you don't understand data structures and do not have solid programming skills in some Visual Basic-like language, Opal is likely to present a difficult learning curve for all but the most basic projects. For overburdened corporate IS managers, however, Opal 2.1 brings the holy grail of updating and Web-enabling existing host-based applications and databases within reach.

An Armory of Problem-Solving Tools Opal's full-featured visual programming language differentiates it from existing screen-scraper and host-based middleware products, including Centura Software Corp.'s ForeSite, Wall Data's Rumba Office and WebConnect Pro's OpenVista. The Opal Integrator development environment, which runs under Microsoft Windows95 and Windows NT 3.5 or 4.0, is a full suite of application development and repurposing tools. It enables everything from direct database access to encapsulating and combining functional portions of one or more existing host-based applications. These applications can then be seen as a single "virtual application" by users running an Opal executable on their workstation (Windows95, 3.1 or NT) or browser (via 16-bit and 32-bit plug-ins for Netscape and plug-ins or ActiveX controls for Microsoft Internet Explorer).

Both Netscape Communications Corp. and Microsoft Corp. have agreed to bundle ActiveX

plug-in versions of the Opal 2.1 Player with their Communicator and Explorer browsers, which should provide a straightforward Internet and intranet deployment of Opal applications.

Opal applications ideally connect via TCP/IP and the native Opal TE (Terminal Emulation) layer to host applications running under IBM/3270 and 5250, Digital Equipment Corp. DEC VTx and Unix/VTx interfaces. Opal uses existing third-party or 16-bit or 32-bit WinHLLAPI (Windows High-Level Language Application Programming Interf ace) layers, such as Attachmate Corp.'s EXTRA! Personal Client and Wall Data's Rumba, but with lower performance and loss of the native ability t o have multiple host sessions open simultaneously. Opal accesses any ODBC (Open Database Connectivity)-compliant database directly through a local ODBC driver, or remotely via TCP/IP through the Opal Server running on a Windows NT host machine.

The bundled application creation Assistants are well-designed and include scripts so you can identify potential data sources; create screen objects; and design or change the scheme, look and feel of the entire interface. Many preset application "themes" are included, such as "Blueprint," "Rainforest" and "Academia," ensuring a consistent look throughout an Opal-based system.

I was generally impressed with Opal 2.1's features. I connected to several sample IBM/5250 AS/400 applications via host-session emulation/encapsulation and directly to an IBM 390 IDMS database with the Opal Server via TCP/IP. Opal did a fine job of grabbing screens and data from the existing applications and transferring them to the "new" Opal application. When using an Opal Server linkin g to an Opal Player, Opal lets developers send the user only those portions of the data from a host-based application or database that are explicitly needed.

In the lab, despite some screen redraw slowness, the application-creation process was smooth and relatively familiar to anyone who's worked with Visual Basic. The documentation is missing some critical information, such as details about the Opal Server component, but this should be corrected in the final release.

Opal 2.1 relieves data migration and accessibility headaches, but it does have some obvious limitations. For example, it can't repair design flaws or performance problems in the original host database(s). Opal adds at least one additional layer to an application, so you should use it carefully to keep performance acceptable. In addition, you'll need to maintain any host-based data sources, as well a s the hardware that supports them. Opal did not handle connecting to an AS/400 through a NetWare for SAA server, and it had some difficulty accurately screen-scraping a Unix-based, menu-driven e-mail program. But it did an excellent job of repurposing and updating existing host-based applications with a minimum of effort.

Richard Hoffman is the Webmaster for www.disasterrelief.org, which provides disaster information and assistance. He can be reached at hoffmanr@usa.redcross.org.