One of the key technological innovations in eCos is the configuration system. This allows the application developers to impose their application requirements on the run-time components in terms of their functionality and implementation. Furthermore, the eCos configuration system and tools ensure that the resource footprint of eCos is minimized by removing all unnecessary functionality and features. More traditional operating systems tend to be monolithic and constrain the application's own implementation, forcing additional functionality and features that are never used by the application.

The configurability system of eCos therefore enables eCos developers to create their own application-specific operating system, negating the need for custom in-house and RYO (roll your own) run-time systems. The configuration system presents eCos as a component architecture, providing a standardised mechanism for component suppliers to extend the functionality of eCos, allowing applications to be built from a wide set of optional configurable run-time components.

Components can be provided from a variety of sources including the standard eCos release, commercial third party developers and open source contributors. This makes eCos suitable for a wide range of embedded uses.