Virtual memeory is that when the available RAM memory is not sufficient for the system to run the current applications it will take some memory from hard disk.This memory is termed as Virtual memory
Computer have different type of memory like primary memory , Auxiliary memory , buffer memory , Cache memory , virtual memory ,
the work of all memory heterogeneously primary memory is directly communicate with the CPU . Auxiliary memory are used for storing the data for long time . Buffer memory are mainly used for storing the intermediate data between the travel . cache memory are used for storing the those data that currently required at process time for increase the speed of the data . virtual memory are put in between the two memory for increase the speed of data or instruction it means it put between HDD and RAM.
There are situations, called hazards, that prevent the next instruction in the instruction stream from executing during its designated clock cycle. Hazards reduce the performance from the ideal speedup gained by pipelining. There are three classes of Hazards:
The latency of the architecture increases with the pipeline stages. Penalty due to the flushing of the pipeline for instance will also increase Cycles Per Instruction of the CPU architecture
Arise a non maskable interrupt.
Then give jump instruction to required subroutine.