The main core of the Experimental Physics and Industrial Control System (EPICS) toolkit.
EPICS Base contains the build system and build tools, common and OS-interface libraries, Channel Access client and server libraries, static and run-time database access routines, the database processing code, and standard record, device and driver support.
The first operational version in the 3.14 series of EPICS Base was released in December 2002. Recent versions in this series are used at many research laboratories worldwide. Future versions in the 3.14 series will only add new build architectures and provide bug fixes.
See the other EPICS Base projects here for later versions and the development series.