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 Philips CD303 of 1983-1984 was the first player to adopt tray loading with a sliding play mechanism. Basically as the tray came out to collect the CD, the entire player's transport system also came out as one unit. The Meridians 200 and 203 players were of this type. They were also the first to use a design in which the audio electronics were in a separate enclosure from the CD drive and pickup mechanism.