Posted by Rick Fowler, TCC Director of Mainframe Services

This is a follow up to my previous post   discussing a whitepaper I read that was published by LzLabs that outlined two methods for migrating applications to a new target environment without rewriting or recompiling the source code. Both utilize a complex rehosting infrastructure to provide a seamless migration. The Software Defined Mainframe – Leveraging “the Power of Modern”. (2017, September). Retrieved February 22, 2018, from

Operating System Rehosting migrates the applications as well as the operating system and subsystems into the new environment. A low-level software program emulates the behavior of computer hardware on a different, target hardware architecture.

The applications interact with the legacy operating system in the same way as before, since the entire software stack of the legacy system executes applications on the new hardware architecture. Unfortunately, this requires the use of additional instructions which add overhead to the application, which can eliminate any potential cost savings. Also, low-level timing problems can result in intermittent problems that are time-consuming to diagnose. This also drives up labor costs for workers with mainframe skills that are in short supply.

While Operating System Rehosting is certainly one option, in the next blog post we will examine the option of Application Workload Rehosting.

To learn more about TCC’s Mainframe Managed Services please visit our website

Click this link to download the whitepaper:




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