TIMER MECHANISM OF ELECTRONIC COMPUTER

PURPOSE:To eliminate the need for a fine adjustment of the oscillation frequency of a timer mechanism by reading the time of the timer mechanism and calculating and resetting a correct elapsed time based upon the last corrected time and advance/delay data on the timer within a specific time. CONSTITUTION:When the power source of a CPU1 is turned on, a service processor 2 reads a program for setting the initial value of the CPU1 out of an external storage device 8 and execute it. At this time, the need to set a CPU timer 15 is eliminated. Then, a no-power-failure timer 11 is read. Similarly, the values of a set time register 12 and a corrected value storage register 13 are read out. The correct current time is calculated from those values. The difference in value between the timer 11 and register 12 is the time from the last power-on point to the current power-on point and calculated as a value including an error of the timer. The advance/delay data within the specific time is stored in the register 13, so the value obtained by subtracting a correction value from the value of the timer 11 is set in the timers 11 and 15 and register 12 respectively. Consequently, the advance or delay of the timer is corrected.