A system and method for executing applications written in a cooperative scheduling environment in a preemptive task scheduling environment, ensuring that the time sequence for the delivery of interrupts is not altered in the preemptive task scheduling environment, efficiently disabling all cooperative interrupts in response to a request from an application, efficiently scheduling all cooperative interrupts, and efficiently executing emulated instructions while preserving the integrity of the emulated instructions. The system and method utilize a process server to enforce the cooperative scheduling, a cooperative interrupt server and a holds queue to enforce the interrupt requirements, and special context data to ensure the compatibility of applications designed using an old instruction set architecture.