the thread control list 24 associated with the standby thread 16 fig3 is an explanatory diagram illustrating the structure of the thread control list 24 the other thread control lists 22 23 have a structure similar to the thread control list 24 and will thus not be discussed the thread control list 24 includes a thread running event control block ecb 24 a and a thread terminating ecb 24 b the thread running ecb 24 a manages the requests received from the thread management circuit 11 the thread terminating ecb 24 b manages termination requests received from the thread termination circuit 12 of fig1 the standby thread 16 runs or stops a program in accordance with information written to the ecbs 24 a 24 b the thread management circuit 11 stores a run request in the thread running ecb 24 a of the thread control list 24 associated with the standby thread queue section 21 b when the run request stored in the thread running ecb 24 a is associated with the standby thread 16 the standby thread 16 runs the program associated with the standby thread 16 in accordance with the information the thread termination circuit 12 stores a termination request in the thread terminating ecb 24 b of the thread control list 24 associated with the standby thread queue section 21 b when the termination request stored in the thread terminating ecb 24 b is associated with the standby thread 16 the standby thread 16 is terminated this frees the system resources that were allocated to the standby thread 16 the standby thread counter section 21 c stores the.