Abstract: A method controls separated running of linked program blocks which are configured for implementing functions of safety-relevant systems. A first program block is executed on a processor, the first program block being present in a first portion of a memory. A second program block is called during the execution of the first program block. The second program block is present in a second portion of the memory, which is different from the first portion. Access to the memory is monitored by a memory protection device, which initiates an exception if it is determined that the second program block is called during the execution of the first program block. An exception handler locks the first portion upon occurrence of the exception and releases the second portion for execution. The access to data is controlled by the memory protection device by use of exceptions and of the locks and releases resulting therefrom.