In-Depth
Why Legacy Databases Are Here to Stay
While industry watchers once encouraged customers to think about transitioning away from pre-relational DMBSes, they’re now backtracking
Pre-relational databases don’t die, nor do they fade away.
Every 18 months or so, vendors such as CA Inc., IBM Corp., and Software AG (among others) roll out improved revisions—complete with new features or enhanced functionality—of their pre-relational database offerings. Early last month, for example, Big Blue introduced a new revision of its Information Management System (IMS) DBMS. Last week, rival CA announced a new version of one of its pre-relational DBMSes, the venerable IDMS.
Pre-relational platforms such as IMS, IDMS, DataCom, and ADABAS are still going strong. While industry watchers such as Gartner Inc. once encouraged customers to think about transitioning away from pre-relational DMBSes, they’re now backtracking, to a degree, from such advice.
In a 2005 report, Gartner analyst Donald Feinberg suggested that customers consider migrating away from pre-relational DBMSes over the next five to ten years. In a recent report, however, Feinberg said organizations should also do a thorough cost/benefit analysis before embarking on any such migration. For many customers, in fact, the risks and additional costs entailed by migrating away from a pre-relational DBMS outstrip the costs (see http://www.esj.com/news/article.aspx?EditorialsID=1991).
IBM and other pre-relational DBMS vendors certainly think the conventional wisdom has changed. As a result, they’re continuing to flesh out their "legacy" DBMS platforms like it’s 1979.
IMS 10, for example, boasts new XML Query language (XQuery) support, enhanced XML and Web services capabilities, Enhanced Database Recovery Control, and a new Dynamic Resource Definition facility. XQuery support opens IMS up to XQuery-enabled business intelligence (BI), data warehousing, and other applications, IBM officials say. As a result, IMS backers see it as a Very Big Deal.
"With IMS 10, standard XML Query language will be available to hierarchically structured data for the first time, delivering unprecedented versatility and information management options to IBM System z customers," said Arvind Krishna, vice president of IBM data servers. "This will help customers simplify their development environments while continuing to realize the proven performance benefits and data integrity of IMS."
Elsewhere, IMS 10 also boasts an improved version of the IMS SOAP Gateway, which now provides z/OS environment, PL/I applications, and Asynchronous Callout support. (IMS SOAP Gateway Web service-ifies IMS transactions.)
IDMS Gets an Overhaul, Too
CA has packed IDMS Server r16.1 with enhancements. The advantage, CA officials maintain, is that even though IDMS itself is more than three decades old, it remains a viable—and, indeed, continuously evolving—platform.
"Many of the applications that were built [for IDMS] in the 80’s or 90’s are still running. In the last 15 or 20 years, CA has really spent our IDMS investment dollars in the usual areas of performance, so we’ve focused on keeping up with the hardware and software improvements. We’ve also spent a lot of our investment over the last 15 or 20 years opening IDMS up to be accessible through industry-standard APIs," says Greg Beedy, director of product management at CA.
"That started with SQL, the relational access, which we made available in the late 1990’s; most people use that to access the existing pre-relational structures. Then, IDMS Server introduced the open drivers for distributed access. What we’re doing here [with IDMS r16.1] represents the next step in that ongoing investment."
The upshot, Beedy argues, is that today—perhaps more than at any time other than during its heyday in the late 1970s and 1980s—IDMS isn’t necessarily an embattled or soon-and-inevitably-to-be-obsolete platform. Customers are staying put. "More and more of our customers are saying that to do more modern development, to build up their infrastructures to take advantage of more of these mainframe assets, it just makes more sense to try to access all of those [assets on the mainframe] than to convert them off to some other platform," Beedy says. Enter IDMS r16.1, which boasts SSL connectivity (via enhanced ODBC and JDBC drivers) for secure communications; support for the auditing of J2EE-based systems (via CA’s SiteMinder Web Access Manager); compatibility with third-party identity access managers; new support for IPv6; and new primary and foreign key metadata support, among other enhancements.
The latter capability makes it easier for customers to access CA IDMS databases using standard SQL functionality. As a result, Beedy says, it helps reduce or eliminate reliance on table procedures for database navigation—which makes it easier to expose IDMS data to development or business intelligence (BI) tools.
"Customers who have IDMS network databases … they aren’t relational, they aren’t normalized, they follow a network data model that’s very sophisticated. To access that with SQL requires IDMS extensions. A lot of times, organizations are trying to use BI tools, code-generation tools, or object-relational mapping tools that look into their catalogues and discover the records of the tables and the relationships. When you do that against a network database that’s pre-relational, you don’t find the relationships," Beedy explains.
"Now … any tools that come in through IDMS Server will recognize those primary and foreign key [metadata] pairs and generate SQL standard and use those relationships. This allows our customers to make their pre-relational databases more relational without the cost and expense of converting to another database environment."
In other cases, Beedy says, the new IDMS enhancements help make that product a better player in the increasingly service-enabled enterprise. "There is more and more interest in opening up access [to IDMS], and if you’re building out an infrastructure of Web services in the SOA range, and that’s typically where a lot of people do it, being able to access the data and the business logic," he comments.
"This release really advances our openness, particularly in the areas of security and also open standards. In security, there’s SSL support so you can have a secure socket coming from the distributed environment into z/OS. There are also compliance enhancements, because more and more orgs care about who’s in there touching the data and changing the data. So [to that end] we’ve got integration with CA’s SiteMinder [identity access] product."
Why Legacy DBMSes Keep Going and Going
Two years ago, Gartner’s take on IMS and other pre-relational databases was terminal: customers should think about migrating off pre-relational platforms over the next five to ten years. One reason posited by Gartner analyst Feinberg was the inevitable drying-up of the pre-relational talent pool.
"As with any aging technology, fewer people are being trained for it. Most colleges and universities are only teaching about these DBMS engines in ‘History of IT' classes. Computer science and business administration students are learning modern technologies, such as RDBMS. In addition, entrants to the job market are interested only in modern DBMS technologies. It is difficult to find trainees for the mainframe, let alone for pre-relational DBMS technologies," Feinberg argued.
These days, some industry watchers are singing a different tune.
"An ongoing IT fear is that as baby boomers start leaving the field, IMS experts will become thin on the ground, and thus the inevitable aging of apps will mean more and more risk of business-critical app failure and greater and greater costs of administration and upgrade by untrained newbies," says Wayne Kernochan, a senior IT analyst with the Illuminata Group. "I believe that these fears are entirely overblown. One of the nicest features of IMS is its simplicity."
Unlike object-oriented programming, IMS requires "relatively little training for programming or administration," Kernochan argues. More to the point, he says, Big Blue has ample opportunity to keep on keeping on as far as IMS is concerned, and CA with IDMS, which has more than 1,000 active customers, is more or less in the same boat:
"[O]dd though it may sound, there is no reason for IBM not to continue to refresh IMS with the latest technologies, to fit its users for integration into SOAs and event-driven architectures of the future."