Development of Hadoop began when forward-thinking software engineers realised that it was quickly becoming useful for anybody to be able to store and analyze datasets far larger than can practically be stored and accessed on one physical storage device (such as a hard disk).
This is partly because as physical storage devices become bigger it takes longer for the component that reads the data from the disk (which in a hard disk, would be the “head”) to move to a specified segment. Instead, many smaller devices working in parallel are more efficient than one large one.
