On the other hand, the new standards-based openness of the mainframe makes it easier for some applications to not only move to the mainframe, but also to move from the mainframe. Thus, should mainframe applications move to a distributed or non-mainframe model; if so, to what extent?
Finally, the applications in today's market differ sharply from those of ten years ago. Most notably, there is a major market for regional and functional independent software vendors (ISV) below the traditional enterprise application (e.g., in-house, SAP, Oracle), which has its own ideas about the role of the mainframe. How should they approach the new mainframe capabilities?
Each of these cases deserves its own consideration, and the correct architecture for each differs significantly, as does the role of the mainframe in that architecture. Overall, however, the answer is that the mainframe should play a less dominant but more extensive role in the typical large-enterprise architecture and in the applications that overlay that architecture. This is beginning to happen.
IBM z9 and enterprise applications
IBM's new support for SAP applications indicates the importance that they place on garnering the mainframe's share of the enterprise application market. While these ISVs are typically computer-vendor-neutral, the mainframe's new strengths do play well to this market. In particular, the zIIP processor improves scalability for the "mixed" (querying and update) transaction workloads typical of this market. In contrast, zAAP focuses on application scalability and DB2 9's new "hybrid" capabilities allow enterprise applications to support the new semi-structured and unstructured data beginning to infuse enterprise applications.
The Linux capabilities support an increasingly popular enterprise-application operating environment and the SOA capabilities are a model that enterprise applications are also embracing.
As these enterprise applications open themselves to SOA, they are increasingly beginning to be distributed across multiple servers. This should induce increasing numbers of instances where previously Unix-only enterprise applications can operate on the mainframe -- but also instances where previously mainframe-only enterprise applications can operate on Unix and Linux boxes.
IBM z9 and in-house applications
Slowly but surely, mainframe in-house applications are opening themselves by converting to Web services providers in an SOA. This plus recent improvements in migration tools makes in-house mainframe applications more readily portable to other environments. But there has been relatively little movement away from the mainframe so far.
Instead, the advent of composite applications has meant that in-house mainframe business-critical applications work in concert with other applications on other systems that also abet business-process improvement. Thus, mainframe in-house applications are not moving to other platforms in great numbers. But users are employing them more effectively in a subsidiary role to an overall enterprise-wide composite application.
IBM z9 and the New Application Providers
ISVs below the traditional enterprise-application suppliers (SAP, Baan, Peoplesoft, Siebel, and so on) are of increasing importance to both customers and the evolution of computer technology. These ISVs are characterized by specialization on a particular vertical market, say, car dealers or manufacturers, or function. In addition, a significant proportion of sales go to SMBs workgroups/departments of large enterprises. The key value-adds that these vertical ISVs bring are ease of application administration in smaller sites, high flexibility and customizability. These features are particularly valuable in markets such as healthcare and retailing. In these markets, development often takes place at the business level based on components specialized for a particular industry or function.
Overall Trends in Mainframe Support of Applications
Table 1 shows how each type of application is reacting to the new mainframe capabilities.
Table 1: Trends in Application Prevalence on the Mainframe
|Application Type||Applications Best Suited to New Capabilities||Applications Least Suited to New Capabilities||Trend|
|Vertical application||Require high scalability, robustness, low TCO for large implementations||Single-server applications leveraging low-cost PCs||Movement towards mainframe-based solutions|
|Enterprise application||Require high scalability, robustness, low TCO||Windows-based enterprise application implementations||Increasing numbers of distributed sites linking Unix/Linux boxes and mainframes|
|In-house application||Require data scalability, want to lower TCO||Not yet converted to SOA||Increasing numbers of distributed sites linking Unix/Linux boxes and mainframes|
Application-location patterns are shifting at a glacier's pace in reaction to the mainframe's new capabilities. The lubricants for the glacier's movement, that is, for changing applications' architectures, are the new capabilities, the advent of mainframe SOA/Linux technologies and better migration tools. The result is likely to be a greater prevalence of applications running on both the mainframe and large Unix/Linux boxes.
All in all, there is no downside in this for mainframe users or application ISVs. The former can certainly find many of their applications more scalable and more flexible if effectively enhanced by use of specialty processors and conversion to an SOA. The latter, if not already aware of mainframe prowess, can certainly find new vendor-neutral reasons for considering the mainframe to be a platform of choice (except, of course, for those ISVs partial to Windows). Like a glacier moving, the benefits will come – slow but sure.