Abstract: A mutual exclusion arrangement is disclosed for use in connection with a computer, the computer being configured to execute at least one program having at least one thread in a series of time slots. The mutual exclusion arrangement includes, associated with the computer, a signal generator and, associated with the at least one thread, a signal handler. The signal generator is configured to generate a signal for provision to the at least one thread when the computer initiates processing of the at least one thread in one of the time slots. The signal handler is configured to, in response to the signal, determine whether the thread, when it begins execution in the time slot, will be executing a section of code that is to be executed in an atomic manner, and, if so, enable the thread to begin execution at a beginning of the section, and otherwise enable the thread to begin execution subsequent to previously-executed code.