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Mainframe migration: Start with a clean slate

When it comes to a mainframe migration, methodical and meticulous is the way to go.

Robert CrawfordRobert Crawford

Robert Crawford has 29 years of experience as a systems programmer. He currently is an operations architect responsible for setting the mainframe strategy and direction for a large insurance company in Texas. In part 1 of this interview, "Mainframe strategy: Invest in and repurpose mainframe computers," he discussed his reasons for staying the course with these powerful computers. Here, he offers his views on mainframe migration. Mainframe migration can be tough. What is the easiest way to migrate data or applications off the mainframe?
If you're trying to get off the mainframe, I would just rewrite the code to run on a distributed platform. I don't see any reason why you'd want to take a huge, mission-critical system and run it on [a distributed platform] that emulates what you were doing on the mainframe. It probably won't perform well.

Emulation software always has holes in it, and you're not really taking advantage of what the distributed platform is doing. You're taking something that was built for one purpose and running it on a platform that really has a different way of doing things -- and that doesn't always work. So, haul off and rewrite it for a distributed platform. Start with a clean design sheet.

If you're trying to get off the mainframe, I would just rewrite the code to run on a distributed platform.

So, how difficult is it to make that transition?
It's a huge effort, and there's a lot of exposure to doing that, because you're going to discover new holes, you have to debug code. Starting from scratch is always tougher when you have something that's been running well for 20 or 30 years and pretty much has all its fixes in it.

How can you move an application off the mainframein a manner that's least disruptive to the business?
It depends on coming up with a plan where you hopefully don't have to throw the switch over the weekend and all of a sudden everything is running on Unix. Move it a piece at a time to the Unix platform. You could move the application to the Unix platform but keep the data store on the mainframe and eventually migrate the data over. You would have to do it based on how the applications are structured in the shop.

There are smart ways to put a [graphical user interface] on the mainframe. Some companies use screen-scraping software on the desktop, basically pushing the text-based screens and presenting it on a GUI. Probably the best way to do it is to expose the mainframe applications as Web services, which are based on open standards.

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What advice would you give CIOs who are being asked why they aren't looking at a mainframe migration to a cloud platform?
The mainframe is like a cloud. The other thing would be to look at the expense and risk of moving off the mainframe -- and the ultimate reward. If the CIO wants to truly answer why an application shouldn't be moved off the mainframe, he or she has to gather some figures. They should ask, "Is this really what you want to do?" then be prepared to say, "It's going to cost us X amount to get off; it will mean we have to expand our data center by this much; we will have to hire this many more Unix system administrators -- and that's just to stay where we are before we can continue doing what we need to do for the competitive market." So, it's a matter of explaining what it really means to be in the cloud to get off the mainframe.

Is it hard to find people to support mainframes and mainframe applications, and how do you work around that?
It's difficult to find experienced people to run the mainframe, but you can do it if you're aggressive enough about recruiting in college and putting them in with the more experienced folks. We've been really aggressive about bringing young people in. A few of them are like, "Geez, a mainframe. Why do I want to work with this?" After they work with it for awhile, they see the value and the skills that they're picking up. There are also other companies that are eager to take on that responsibility for you.

Let us know what you think about the story; email Christina Torode, Executive Editor.

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