Disparate system

In information technology, a disparate system or a disparate data system is a computer data processing system that was designed to operate as a fundamentally distinct data processing system without exchanging data or interacting with other computer data processing systems. Legacy systems are examples of disparate data systems, as are heterogeneous database data systems. A disparate system is often characterized as an information silo because of the data system's isolation from or incompatibility with any other data systems.