User:Hireasian/Mainframe Migration/

Mainframe Migration refers to migrating software applications from the old IBM Mainframe and other legacy systems to modern Open Source (Unix) or Windows platforms, utilizing the latest technologies and frameworks. Since there are plenty of existing applications and very large number of line of source code in the old languages, re-writing all these programs in the modern languages are not always practical and cost effective. Hence most of the time, a "Lift & Shift" methodology is adopted, wherein the original source code (Cobol etc.) is recompiled on the target platforms using specialized compilers. For certain old languages on mainframe like "Quickjob" there are no expertise or documentation available, and may require reverse engineering and re-writing those programs in modern languages. The same may be true for 3rd party old tools on mainframe. Some of these tool vendors have brought out mechanisms by which the original programs (Control Cards) can be directly ported to Unix/Windows.

The main reasons for people trying to offload old mainframe systems are due to: (1) High maintenance cost. (2) Non availability of resources and expertise (3) Only very few vendors to choose from, when you want to extend or modernize. (4) With the advancement of technology, high end PC or Unix servers can produce similar speed and efficiency of those old legacy systems. (5) In many cases, applications does not require the very high security and other features provided by legacy systems. ( ie; under utilization of mainframes at a very high investment ). These are the candidates ideal for migration.