1.1.3 Outline compatibility issues resulting from situations including legacy systems or business mergers.
A legacy system refers to outdated computer systems, programming languages or application software that are used instead of available upgraded versions.
A legacy system is not necessarily defined by age. Legacy may refer to lack of vendor support or a system’s incapacity to meet organizational requirements.
The system might work adequately.
Defining the scope of the system can be difficult, especially when the documentation is poor.
A redesign is costly due to the complexity of the system.
Cost -- The following might cause expense:
It may require training of staff or hire new employees.
New hardware may need to be purchased for the system.
Time consuming implementation, using up employee time for the transition between systems.
It may require a complicated process of data migration.
Software incompatibility is a situation where different software entities or systems cannot operate satisfactorily, cooperatively or independently, on the same computer, or on different computers linked by a local or wide area network
Historic data may not have to be converted into the new system format.
Cannot keep updated with latest technology (incompatible).
Legacy systems are high maintenance and may involve intricate patching and modifications.
Character encoding systems may differ (e.g. ASCII vs. Unicode). Support for international characters may vary.
Database systems may be different (e.g. SAP / Oracle / MySQL etc.).
Issues with usage rights of proprietary systems.
Conflicting work cultures of those working with the systems.
Conflicting organizational goals, which is an issue especially in international mergers.
is the combining of two or more business entities. During this process all departments of both companies need to ensure that all subsystems are compatible.
The main reason companies merge is to reduce cost
Keep both information systems, and develop them to have the same functionality (high maintenance cost)
Replace both information systems with a new one (increased initial cost)
Select the best information systems from each company and combine them
Select one company's information systems and drop the other (could be tied to policy problems)