Abstract: For establishing two-way communication links between processes in a distributed operating system, the processes are provided with ports through which communication between the processes is performed. The processes and the ports make possible for the operating system to keep a check on processes having links and to use these links also if the process per se is terminated, and to discover an error in the process and terminate it. For enabling the operating system to be able to transmit via the links information regarding process or computer drop out and thus be able to propagate this information through the whole chain of linked processes, and to report this information to applications executed in the linked processes in order to enable these to undertake application specific measures, a code is used which is called at link abortion and communication errors. The function of this code includes terminating an erroneous process and reporting the error to an error handling code.