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e -server magazine

January 1997: Volume 12, Number 3

AS/400 Client Server: Past, Present and Future

By Janet Krueger

f you review all of the AS/400 announcements made in 1996, you’ll have a tough time finding the phrase client/server anywhere. Did the AS/400 move into the client/server era, only to find that the technology is now passé? AS/400 business partners have been scurrying to produce client/server versions of their applications; if they are just introducing them now – did they miss the opportunity window? Fortunately, if you acquired client/server skills during your struggle with the AS/400 metamorphous from a host system to a server, there is still time to market those skills; AS/400 client/server solutions will help you move forward into the 21st century!

Before looking at how AS/400 server solutions will continue to evolve, including both technology transitions and new vocabulary words, it would be helpful to review our history. The AS/400 was introduced in 1988. It combined the best features of the System/36 and the System/38, and supported thousands of applications. PCs, running the IBM DOS operating system, could be attached locally or dialed in remotely. The PCs could alternate between functioning as AS/400 5250 terminals and running personal productivity applications such as word processors. The AS/400 application base was primarily text-based, built using RPG or COBOL code and DDS specifications; there were no client/server applications in the portfolio. Copies of PC programs and data could be stored in AS/400 folders, and a simple file transfer function allowed users to extract data from the AS/400’s relational data base. The data could then be imported into PC spread sheets for analysis; direct access from PC tools was not supported.

During the next several years, PC usage rapidly evolved. Graphical, multi-tasking operating systems were introduced, and more and more PC applications were developed. Although the AS/400 did support a form of PC file serving, called shared folders, it was too slow to support the level of sharing and service the PC users demanded. So PC users started forming work groups by implementing local area networks and adding PC-based servers. This started the protocol coexistence battle on the networks; PC servers used IPX or NetBIOS for the base protocol while the AS/400 used APPC; making both work together on a single PC provided a never ending challenge. And once users had connectivity to both PC servers and the AS/400, the AS/400 text-based interfaces looked drab and outdated compared to the flashier PC-based interfaces. The AS/400 had two alternatives: it could allow itself to be branded a dinosaur and gradually be pushed into the back closet, or it could become a modern server. The choice was not hard to make; the transformation from a host-based system to a server is now complete.

If you think back to the early ninety’s, you may recall the phrases “Cooperative Processing” and “The Best of Both Worlds”. Initially, we built solutions that uniquely tied the AS/400 and PCs together, with the assumption that if the AS/400-PC connection was best of breed, you wouldn’t need any other servers. There were two problems with that approach. First, in many enterprises other servers were already installed and removing them was not an option. Proprietary AS/400 connectivity code was viewed as an irritant, rather than a feature. Secondly, when companies evaluated strategies for modernizing their application sets, they leaned toward solutions that would leverage the new PC-based productivity tools and support multiple server platforms; AS/400 proprietary enablers don’t fit this paradigm. So IBM has now moved to a strategy of supporting open, standard interfaces wherever possible, with most AS/400 development resources focused on optimizing those interfaces.

A complete suite of open servers is provided as part of OS/400 Version 3. This includes both a standard set of TCP-based services and a specialized set of servers for Client Access and other AS/400 connectivity products. The results of refocusing AS/400 development can be seen in the newest client for the AS/400, Client Access/400 for Windows 95/NT, where the fastest interface for accessing DB2/400 is through industry-standard ODBC (Open Data Base Connection) over a native TCP connection. Other functions provided by Client Access include client/server application enablers, 5250 display emulation, print serving, graphical access to all OS/400 interfaces, support for a repository of multimedia objects, client management, and mail serving. Numerous other client/server products are also provided for the AS/400, including a full suite of data warehousing offerings. And many AS/400 applications have been enhanced with client/server capabilities; if you check the AS/400 Client Server Applications Directory, found on the Internet at http://www.softmall.ibm.com/stores/as400, you’ll find references to over 4,000 solutions!

In situations where a PC-based file server is required for optimum performance, the AS/400 now offers a hardware option called the Integrated PC Server (previously called the FSIOP), which provides a PC server under the AS/400 covers. Currently, this supports an OS/2 based LAN server, NetWare, or Lotus Notes.

So, if the AS/400 is already a full server, what’s left to do? IBM will continue to improve performance, especially in the area of database access, by combining continued reductions in price/performance of AS/400 hardware with software improvements in communications, data buffering, and query optimization. We will also continue to simplify client installation and connections into the AS/400. We are introducing “Project Unity”, an entirely new way to view OS/400; instead of providing graphical views of existing OS/400 interfaces, we are extending the Windows 95/NT desktop with full access to OS/400 operations; users with Windows expertise will find the AS/400 to be a natural part of their world, requiring very little additional experience, rather than the foreign object that it often seems today. Products currently supported only with an Integrated PC Server, such as Lotus Notes, will be ported to run natively on the AS/400; this will allow additional integration with OS/400 and AS/400-based applications. The Integrated PC Server itself will also be enhanced; new hardware options will include faster PC processors and additional memory, and software support for Microsoft’s NT server will be provided.

And with the movement to Network Computing on the Internet or Intranets, is client/server even relevant? If you look beyond the new buzz words, you’ll find that network computing is a variation of client/server technology; using the TCP protocol, it leverages an “open” network to provide a client with access to resources on one or more servers. The new Network Station, which on the surface seems to be a 5250 terminal replacement, is just a new kind of client, including both a 5250 terminal emulator and a standard Web browser with full support for Java applets. Today, the AS/400 (at V3R2 or V3R7) can act as a web server; hence our new “Web Without the Wait” message. An administrator can set up home pages, including live links to DB2/400 data. And any user with a standard web browser can have access to all text-based AS/400 applications; the 5250 datastream is dynamically converted to HTML (Hyper Text Markup Language). Additionally, new client applets can be written in Java, and delivered to clients running a standard Web browser. In fact, the functions supported by network computing are equivalent to the PC server functions that were provided by the AS/400 at its introduction 8 years ago! As network computing is expanded to support a full range of mission critical, enterprise applications, all of the processing modes currently found in PC client/server solutions will be added. In fact, some of them are even being named the same; the data base access component of Java is being called JDBC, and will leverage all the critical skills required for installing and tuning today’s ODBC solutions.

These offerings will be enhanced in the future with increased performance and additional firewall capabilities. Soon we will also be offering an AS/400-based Java environment. The biggest challenge will be extending access to the full suite of existing AS/400-based client/server applications. We could wait for them all to be re-implemented using Java; some of the OS/400 client/server projects, such as Unity, are already being redesigned. And some of the graphical presentation tool sets, such as GUI/400 and GUISYS/400, will be able to offer development environment upgrades that automatically generate JAVA-based screen definitions. But what about other client/server implementations – one of the largest strengths of the AS/400 has been our ability to transparently bring forward the full suite of existing applications; after all, how else could we have been the first 64-bit system with *all* applications and operating system code 64-bit enabled? Expect some additional support to be added here, although it is too soon to speculate on exactly how we’ll solve the problem.

Only one thing is definite in the computing industry; change will continue at an escalated and frenetic pace. Because we intend to keep the AS/400 competitive, it will also continue with a rapid rate of change; but it will also continue to be a rock that stable solutions can be built on. Rather than being closed off from all the new technology; AS/400 client/server solutions should be able to leverage the changes without breaking. T < G