Application Migration from Ultrix to Linux Operating System

During the recent twenty years there has been substantial investments aimed to migrate legacy application hosted on legacy operating systems to modern applications to be host on modern operating systems, This process can be expensive, both in terms of actual cost and the risk, the migration will lead to changing core applications and can significantly change the way the entire organization operates. Legacy systems are successful and therefore mature, and likely have been in existence for a long period of time. A consequence is that legacy software is built using technologies available at the time it was constructed, as opposed to the most modern software technologies. Older technologies are more difficult to maintain, and this is a key point of pain for many legacy system owners. The aim of this paper is to get a generic methodology for migrating application hosted on legacy UNIX (Ultrix) or its derivative to be hosted on modern Linux operating system. We have already got a legacy application hosted on Ultrix operating system as a case study and we will perform a successful migration to be host on Linux operating system through our proposed migration methodology.
Simply the idea of our proposed method lies in getting the architectural and functional differences between Ultrix and Linux in order to get the best method for migration. The assumption is that RedHat and other Linux variants, being similar to Ultrix isn’t strictly true. After we had understood the functional differences between Ultrix and Linux, we had mapped
system calls to a correct corresponding system calls in new modern platform in order to maintain the same behavior of application and overcoming the problem of endian. Moreover, there are differences in compiler options, building options, the synchronization methods used and signals. Furthermore, we got a methodology to migrate legacy Fortran code and Ingres database to modern ones. This paper organize into five sections, section one, introduction and overview on the Ultrix and Linux history, section two, challenges facing legacy application and why most organizations nowadays concerning with migration, section three, our proposed migration methodology and how overcoming the issues mentioned above in abstract, section four, summary and conclusion, and section five, references.