unambiguously cause all processors in the system to correctly accept messages relating to abort processing and to prevent processors from accepting new subtasks for the aborting transaction which may be in transit in the system the next four states in the tabulation of fig4 correspond to those previously given except that the 34 valid 34 bit is set to 1 representing the processor which reserved the dynamic group thus in 100 and 101 neither normal nor abort messages will be received while in 110 both types of messages will be received the 111 state will initiate the abort procedure and result in ultimate release of the group and reversion to the available 000 status word at all the processors note that it is not required that the processor which allocated the group be a member of the group in fact this is typical in the preferred implementation operation of the system of fig1 4 may be better understood by reference to the flow charts of fig5 and 6 in fig5 the overall sequence involved in setting up a dynamic group and distributing subtasks from an ifp to two related amps is set out with status word changes indicated the flow chart of fig6 shows more specific steps undertaken at one of the amps in carrying out its subtasks and terminating its relationship the sequence of steps shown in.