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. Our example hazards have all been with register operands, but it is also possible to create a dependence by writing and reading the same memory location. In DLX pipeline, however, memory references are always kept in order, preventing this type of hazard from arising.
It was actually a few years later, in the year 1898 to be exact, when this idea had taken its existence. Vlademar Poulsen was the person who had invented the earlier concept of Oberlin. In 1928, Fritz Pfleumer developed the magnetic tape. But it was not that compact as how the modern cassette player was.
The first working prototype was produced in 1979, and CD players were released in 1982. Sony introduced the world's first CD player, the CDP-101 on October 1st, 1982. It hit the market with a retail price of about $900 and featured the now familiar slide out tray loading mechanism for the first time.