Josep Vidal UPVLC jvidal@disca.upv.es Ismael Ripoll UPVLC iripoll@disca.upv.es 2003 OCERA Consortium RTLinux PSignals PTimers Real-Time, POSIX, scheduling Application-defined scheduling (ADS for short) is an application program interface (API) that enables applications to use application-defined scheduling algorithms in a way compatible with the scheduling model defined in POSIX. Several application-defined schedulers, implemented as special user threads, can coexist in the system in a predictable way. The application defined scheduler in RTLinux is a key facility which will help in the adoption of the already available scheduling theory.