Method for providing a fault-tolerant global time and fault-tolerant transport of time-controlled messages in a distributed real-time computer system comprising external computers and a fault-tolerant message distribution unit , FTMDU, wherein each external computer may be an external sender and/or external receiver of messages, in particular of time-controlled messages, characterised in that the FTMDU comprises at least four components , a first component , a second component , a third component , and a fourth component , wherein each of the four components is connected to the other three components of the FTMDU via two or at least two independent communication routes, and wherein said four components , after a power-up of the FTMDU, establish a fault-tolerant global time and maintain it during operation of the FTMDU by means of internal synchronisation messages , and wherein the four components provide the global time to the external computers by means of periodic external synchronisation messages , and wherein the external computers set their respective local clock state to the received global time, and wherein at periodic transmission times, determined a priori in time tables and expressed in global time, each external sender of a time-controlled message transmits two message copies of the message to be transmitted via two different communication channels to two different components of the FTMDU, and wherein said two message copies are delivered within the FTMDU via two independent communication routes to those two components of the FTMDU which are connected via communication channels to an external receiver of the message, and wherein the external receiver checks the validity of an incoming message copy and accepts that valid message copy which arrived first and discards the second, later arriving message copy. the FTMDU comprises at least four components , a first component , a second component , a third component , and a fourth component , wherein each of the four components is connected to the other three components of the FTMDU via two or at least two independent communication routes, and wherein said four components , after a power-up of the FTMDU, establish a fault-tolerant global time and maintain it during operation of the FTMDU by means of internal synchronisation messages , and wherein the four components provide the global time to the external computers by means of periodic external synchronisation messages , and wherein the external computers set their respective local clock state to the received global time, and wherein at periodic transmission times, determined a priori in time tables and expressed in global time, each external sender of a time-controlled message transmits two message copies of the message to be transmitted via two different communication channels to two different components of the FTMDU, and wherein said two message copies are delivered within the FTMDU via two independent communication routes to those two components of the FTMDU which are connected via communication channels to an external receiver of the message, and wherein the external receiver checks the validity of an incoming message copy and accepts that valid message copy which arrived first and discards the second, later arriving message copy. <EOS>