V. V.Nikiforov, V. I. Shkirtil
Execution of the real-time system (RTS) program application will be predictable in the sense of timely performing of its functions. In the case of distributed systems such predictability may be achieved through applying special methods for estimation of message timely delivering between system nodes. Communication channels of distributed systems are hardware resource that should be distributed dynamically between transmitted messages. In the systems with CAN interfaces the ordering of communication channels allocating to the messages that are ready for transmitting is defined by statically assigned priorities. Any low priority message, generated in a network node, should wait a time moment, when the channel become free from transmitting higher priority messages. These circumstances are the cause of mutual interference of messages: the time of message delivering by network with CAN interface depends not only on hardware performance and message length, but also on loading the network by higher priority messages. Such interference is similar to task interference in mono-processor RTS with multitask software application. That is why methods, which are developed for estimation of task feasibility in mono-processor RTS, may be adopted to checking timely message delivering between system nodes. In particular case, the analog of UB-test method (that is used for checking multitask application feasibility) may be used for the aim of timely message delivering checking in the distributed RTS with CAN interface.