As indicated in Figure 1, IDEA is subdivided into an asynchronously and synchronously executing part: pro-logue and epilogue. The transition from prologue to epi-logue is performed by the guard. Using flange , a prologue is attached to some CPU exception vector and will be im-mediately started upon signaling a hardware interrupt to the CPU. An epilogue is considered a prologue continuation and will be started only if granted by the guard. The guard takes care of the serialized execution of these epilogues.