A method for the deterministic or quasi-deterministic execution of an application within a multitasking system, characterised in that said application is made up of at least one task, the timing of which is specified in a first timing reference, called first external clock domain, that is asynchronous relative to the physical time and is defined by a synchronous basic clock with changes of state of a peripheral device of said system, said method comprising at least the following steps executed by said system upon receipt of an occurrence of an interruption: - checking whether the received interruption is authorised by said system; - time-stamping the received interruption; - verifying that the instant of occurrence of the interruption complies with the specified occurrence constraints and notifying the application if this is not the case; - if the received interruption is synchronous with the basic clock of said first external clock domain, in other words if it is a source interruption of said first external clock domain: • incrementing a counter of occurrences of the received interruptions, with the current value of said counter of occurrences corresponding to the current time in said external clock domain; • identifying the tasks that are currently being executed, for which the deadline is equal to the current value of the counter of occurrences of the received interruptions, signifying a violation of the deadline; • transferring the tasks, for which the activation date is equal to the current value of the counter of occurrences of the received interruptions, from the list of tasks in an idle state to the list of tasks ready to be executed on said system; - marking, if said multitasking system comprises at least one process per interruption and the received interruption is either asynchronous with the basic clock of said first external clock domain or is asynchronous with the source interruptions of a physical clock domain, upon receipt of said asynchronous interruption, the phase for processing the received interruption as being executable and making the data needed for said application visible within said first external clock domain; - acknowledging the received interruption and authorising the receipt of new interruptions. - checking whether the received interruption is authorised by said system; - time-stamping the received interruption; - verifying that the instant of occurrence of the interruption complies with the specified occurrence constraints and notifying the application if this is not the case; - if the received interruption is synchronous with the basic clock of said first external clock domain, in other words if it is a source interruption of said first external clock domain: • incrementing a counter of occurrences of the received interruptions, with the current value of said counter of occurrences corresponding to the current time in said external clock domain; • identifying the tasks that are currently being executed, for which the deadline is equal to the current value of the counter of occurrences of the received interruptions, signifying a violation of the deadline; • transferring the tasks, for which the activation date is equal to the current value of the counter of occurrences of the received interruptions, from the list of tasks in an idle state to the list of tasks ready to be executed on said system; • incrementing a counter of occurrences of the received interruptions, with the current value of said counter of occurrences corresponding to the current time in said external clock domain; • identifying the tasks that are currently being executed, for which the deadline is equal to the current value of the counter of occurrences of the received interruptions, signifying a violation of the deadline; • transferring the tasks, for which the activation date is equal to the current value of the counter of occurrences of the received interruptions, from the list of tasks in an idle state to the list of tasks ready to be executed on said system; - marking, if said multitasking system comprises at least one process per interruption and the received interruption is either asynchronous with the basic clock of said first external clock domain or is asynchronous with the source interruptions of a physical clock domain, upon receipt of said asynchronous interruption, the phase for processing the received interruption as being executable and making the data needed for said application visible within said first external clock domain; - acknowledging the received interruption and authorising the receipt of new interruptions.