YME Engineering Course

B. SYSTEM OVERVIEW
If the computation results from CPU1 and CPU2 do not match, the collator
judges that a computation error has occurred, and the control will be
transferred to the standby side. The standby processor unit performs the
same computation as the control side, even though it is in the standby
state. Therefore, it can immediately resume the output of control
computation data to the bus interface when it takes over the control
Therefore, CPUs within the same unit collate each other’s computation
data, being sure to detect any computation errors. Because the unit on
standby performs the same control computation concurrently with the
control side (even though it is in standby status), it takes over the control
computation at any point of time without interruption (bumplessly). This is
called the pair and spare function of the CPU card.
YME Training Center
B-14
CS3KR3-ENG 1 ST Edition Jan 2002