Logo: TUG TORONTO USERS GROUP for Midrange Systems
e -server magazine

November 1996: Volume 12, Number 2

A Formula for AS/400 Application Modernization

How to race with a New Generation of Technology - Part II

By Mark Buchner

t the last TUG meeting I spoke about the process of modernization which requires a road map that navigates the many aspects of technology, tools & methodologies, and management. Let's focus today on these technologies, their associated buzzwords, and how they can be included in your plans:

Client /Server - GUI Building

This is a relatively simple technique which exploits the block mode user interface style of the 5250 panels, intercepts the incoming 5250 data stream and then replaces it with a bitmap image. Controls such as function keys and enter keys are "translated" to mouse clicks. GUI (Graphical User Interfaces) building can be anything from automatic "black box" style redisplay to a replacement of the interface with a mouse-driven GUI. These can be virtually indistinguishable from Windows interfaces. The process of customizing and creating individual panels can be accomplished using a number of tools available in this category. The most recognized products are GUI/400 and GUISYS.

Client-centric Visual Development

Using rapid application development techniques (called visual development), a GUI style, ("event driven programming") combined with modern fourth-generation languages has resulted in an enormous explosion of high-productivity programming environments. These range from Visual Basic, PowerBuilder through Progress to products like Borland's Delphi. In the end, these products rely on developers of client/server applications to use standard SQL calls to access and update data. This compares to the proprietary, 3GL (DDS, RPG) method of old. Even though SQL use was possible in the past, developers rejected it for production systems because of high performance overheads. With the new creation of DB2, combined with working, high-performance ODBC middleware, we now expect SQL-based data access to be on par with native access. This, itself, has opened a new frontier in AS/400 application development.

Distributed Logic Development

This is the "high tech" area of client/server application development. It features products like Synon's Obsydian, Seer's HPS, or IBM's VisualAge for RPG, that allow creation of applications which utilize the server as more than just an SQL engine. They carry notions of re-usability because of their object orientation. Visually building an application from a collection of parts, re-using existing industry framework for vertical market segments and exploiting the value of class libraries are ways these products promise us better, more complete application solutions for less money.

Data Warehousing

Fundamentally, data warehousing provides a new class of data: OLAP (On Line Analysis Processing), typically using a separate processor. Coupled with appropriate end user/analysis tools, this architecture allows the analysis of the data to not interfere with day-to-day transactions. But a further important component is the replication/propagation technology that allows you to transform and copy data efficiently from OLTP to OLAP format. One finds that many of the principals of OLAP are completely opposite to OLTP - for instance, the level of normalization and the redundancy of data.

From an IT perspective, concepts such as data warehousing, data mart, decision support, on-line analysis processing, and data replication all share a common theme. They all require the movement and copying of large volumes of data within the central system, and from system to system.

The performance characteristics of the data transfer are largely determined by the connectivity scheme that is used. AS/400 Client Access software provides connectivity from PC-based platforms to the DB2/400 tables, using Microsoft's ODBC and remote SQL support. This automates the already extensive connectivity of the AS/400. In addition, there are many data mirroring products available to provide data distribution and replication, like DataMirror and OMS.

However, connectivity is only half the problem. If large amounts of data must be moved in order to provide a small amount of information, there will always be a performance problem, no matter what the connectivity. This is why information warehousing architecture is important.

For many, a Data Warehouse is not just a luxury, it is a matter of competitive survival. This technology will yield huge dividends and offer significant leverage points as it weaves transaction information into meaningful trends and causal relationships. These, in turn, will translate into huge competitive advantages in order processes, distribution control, merchandising systems and, most importantly, profitability.

Network Computing

Lastly , there is the hot topic of Network Computing. AS/400 customers will want to deal with three aspects, probably in reverse order of the hype surrounding them.

First is the general question surrounding your business need for Internet-based applications and servers. The Internet provides real opportunity to access your customers, and vice-versa on an open, cost-effective basis. Application developers will note that Internet access requires a standardization on TCP/IP interfaces and will likely require a security audit or building of appropriate firewalls and partitioning for your existing applications. This will ensure that the Internet allows access to only the public aspects of your business.

From there, users will note that new software products and AS/400 components available for V3R2/7 will allow existing AS/400 applications to be accessed through an HTML interface - that is, through standard Internet browsers like Netscape. Of course, this is done in conjunction with your business plan for making communication with customers through the use of the ubiquitous home page.


The biggest buzz surrounds the programming language Java. This goes beyond the highly graphical interfaces provided though home pages and allows actual applications to be integrated as well. These applications are stored as bytecode on the server and are sent to, and interpreted by, the client as they are requested. This necessitates merely a Java engine and is not dependent on a specific client operating system. Hence, much of the fuss about new network computers and the elimination of the dependency on a specific client operating system. JAVA, itself represents one of the most exciting programming languages in many years.

Internet, Client/Server and Data Warehousing. None of these technologies can be accomplished without the use of the ever increasing, ever dynamic set of tools and development products available. We highly encourage readers to identify their needs and establish their own modernization criterion. We hope this article will encourage you further. In the race with a new generation of technology there will be no vendor who will be the outright winner - only the customer who carefully matches their needs will be victorious. T < G

Mark Buchner is president of ASTECH Solutions Inc. in Aurora Ontario, specialists in AS/400 systems. He can be reached at 905-727-2384 or by fax at 905-727-0362.

[Mark was a speaker at the September '97 TUG Meeting of Members]