Evangelizing Mainframe
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IMS: There’s Still Life in the Old Dog!

IBM Information Management System (IMS) first saw the light of day in 1968—before Neil Armstrong and Buzz Aldrin first walked on the moon. In fact, IMS began life as a bill of materials program for the Apollo program. And knowing that the software celebrated its 44th birthday on Aug. 14 might make you think it’s completely out-of-date and of no interest to current mainframers. But you couldn’t be more wrong.

IMS is one of those pieces of software that make up the backbone of financial institutions across the globe. And the reason it’s so important is because it provides a way of storing large amounts of data securely, and, more importantly, in a way that makes it accessible quickly. So IMS (like CICS) is a database and transaction processing system. Most of that data is stored in special hierarchical databases—you’ll hear people talk about “full function” databases, “fast path” databases and High Availability Large Databases (HALDBs). The transactions it uses can be written in many different programming languages, from traditional COBOL to more modern ones like Java.

But don’t think IMS runs in some kind of time warp where, although the data and hardware are new, everything else comes from the 1970s. This just couldn’t be further from the truth.

Many sites use relational databases like DB2 as well as IMS. A number of products from different vendors allow IMS data to be successfully exchanged with DB2. Why would you want to do that? Well, it provides users with a method of querying their data outside of IMS, and it allows IMS to coexist with newer applications. However, users face numerous challenges to achieve this successfully, such as dealing with keys, various data-field challenges, repeating groups, and what to do with non-keyed segments, for a start. But it can be done.

Many sites need to Web-enable their IMS transactions. Again it’s been possible to do this with IMS for years. It means users can be working through a browser—which could be on their laptop, tablet, or smartphone—and accessing the data they need (and are authorized to see). Web Service Definition Language (WSDL) needs to be created from the transaction to Web-enable it.

And, of course, once you have WSDL, you can have mash-ups. That means you can combine transactions from mainframes or elsewhere on the Web and create a completely new application. A user, using any browser-supporting platform can then make use of this new mash-up application. Examples include a map taken from, say, Google, and overlaying it with other information, say average house prices, so when you go to a new area, you can look for a property in the appropriate color band that matches your income.

And WSDL makes it possible to connect easily to CICS and IBM WebSphereMQ applications that also have WSDL. You can create a single piece of business logic (as far as the user is concerned) that actually involves transactions taking place in IMS, CICS and MQ. Using Simple Object Access Protocol (SOAP), structured information can be exchanged as a Web service. An alternative Web service design model is Representational State Transfer (REST). IMS can use both.

On top of that, it’s possible for IMS to make use of external services, such as those from Oracle and SAP. The IMS transaction can call an Oracle or SAP service, and include additional data and transactions as part of the complete unit of work.

Similarly, IMS can communicate with Microsoft software running on x86 platforms. Using open database connectivity (ODBC), it’s possible to share IMS data with Excel spreadsheets. And in the same way that IMS can use Oracle or SAP services, it can call external services in SharePoint.

So, that old IMS system allows you to be bang up-to-date and use your IMS data with new software, incorporate your IMS transactions with new or existing software packages, run services on or off the mainframe, and make calls to distributed systems.

Pretty youthful when you think about it!

Trevor Eddolls is CEO at iTech-Ed Ltd., an IT consultancy. For many years, he was the editorial director for Xephon’s Update publications and is now contributing editor to the Arcati Mainframe Yearbook. Eddolls has written three specialist IT books, and has had numerous technical articles published. He currently chairs the Virtual IMS and Virtual CICS user groups.

Posted: 9/18/2012 12:16:53 AM by Trevor Eddolls

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