At the end of each fourstep cycle the machine can be viewed

Solution

Solution:-

After a end four step cycle the machine is stopped and waiting for the next instruction, at that point preservation of current data is essential. Internal data which is altered during the cycle must be preserved in order to perform next cycle.

During a cycle instruction is fetched from memory address and after execution intermediate results are produced and values of internal registers are changed. Some memory location are also altered when storing some data to memory addresses. Some flag values are set also.

So after completion of a cycle, at that point a machine is in sensitive situation. If we want to stop machine at that point then all the altered value of internal registers and flag must be preserved and intermediate results are also preserved in memory. So that when machine starts execution in next cycle then preserved data can be loaded from hard disk and execution performed in required manner.

End of the day we can say that if machine stops after a cycle and waiting for next cycle then at that point data must be preserved in order to perform next cycle from the point where execution halted. Internal registers data, altered memory addresses, flags status and intermediate results are the crucial data which must preserved.