I only understand in simple words that there are Three types of Pipelining Hazards

1)Resource Hazards

this type of hazards occur when the two instructions require the same resource at same time.

2)Data hazards

suppose there are two Registers or operands values A and B to be used

like Add A,B

Sub A,B

then during the timing signals it maybe possible that two instructions require it both simultaneously at same time then this is data hazards

3)Control hazards

it occurs when the two branching condintion if else both are required at the same time

Now there are three types of Data hazards ie RAW WAW WAR

please explain

What is Write after Write, Read after Write , Write after Write

Please please please please please

A hazard is created whenever there is a dependence between instructions, and they are close enough that the overlap caused by pipelining would change the order of access to an operand.

Consider two instructions i and j, with i occurring before j. The possible data hazards are:

RAW (read after write) - j tries to read a source before i writes it, so j incorrectly gets the old value. This is the most common type of hazard and the kind that we use forwarding to overcome.

WAW (write after write) - j tries to write an operand before it is written by i. The writes end up being performed in the wrong order, leaving the value written by i rather than the value written by j in the destination.

WAR (write after read) - j tries to write a destination before it is read by i , so i incorrectly gets the new value.