read only memory prom random access memory ram read only memory rom flash memory dynamic random access memory dram static random access memory sram system memory or the like the processor 21 accepts data from memory 31 or storage device 22 over the local interface or bus 23 direction from the user can be signaled by using an input device s for example a mouse 24 keyboard 25 or the like the action input and result output are displayed on the display terminal 26 illustrated in fig2 is the well known method of updating a running process normally when a process 41 is to be updated on line the program calls a state saving routine 42 that saves the state information of the program executing in process 41 process a to a data storage area usually a file once the state data is saved process 41 terminates and process 51 process b is executed process 51 retrieves the state data utilizing the retrieve state data routine 52 then while process 51 is not done it performs the program task and if an update is requested then it is done and it continues the loop processing and repeats the steps in program running in process at 51 this method is time consuming and requires an extra data storage area for saving the state information illustrated in fig3 is online replacement of a program running in a process using the checkpoint system of the present invention as current process 61 executes old program 62 old program 62 continuously checks to see if it is done while the old program 62 is not done old program 62 performs the program tasks.