System migration is the act of transferring data and programs from one computer system to another. This may involve physical system migration, when old hardware devices are no longer capable of meeting the needs of the system or these components have been damaged. It may also take the form of a data based migration, in which files and data are transferred to a new operating system.
As technology advances, hardware and operating systems become outdated and limited. A system that is initially on the razors edge of new technology is sometimes obsolete within a few years. Many corporations and organizations find that the software and hardware used in their mainframe computing systems are unable to compete with modern network server systems. To maintain a competitive edge, it is sometimes necessary to migrate stored information, such as data and programs, to a newer system.
When system migration is purely data-based, the move to the upgraded system requires only the transmission of data. Migration software is available to automate the process for many computer operating systems. With advances in software engineering, many modern programs will work in a backward compatible mode. These programs are able to read and write to older data files or convert them to a usable format. In some cases, older programs must also be transferred to ensure accessibility to data in file systems that do not have a modern equivalent.
A physical system migration is the transfer of the entire system, including data and programs, to a new physical computer. This procedure is often necessary when replacement parts are no longer available or economically feasible for outdated mainframe computer systems. In some cases, the outdated system is unable to meet with reasonable processing requirements and requires upgrades. Rather than invest money in upgrading or repairing an outdated and limited mainframe system, some companies and organizations purchase a new network server system. The entire operating system is then cloned to the new system. Data and programming files are then transferred to the new server as well.
Data-based and physical system migrations may be subject to downtime, a period during the transition in which system files cannot be accessed. To minimize downtime, information technology (IT) professionals generally recommend that software maintenance, proper backups, and planning for alternative access to files are in place during major system-wise changes. In some situations, gradual system migration is used to move groups of files over a period of time to avoid total disruption of productivity.