Difference between Sequential ,Direct and Random acess with their acess time
Sometimes, depending on the sources,direct access and random access are used to express the same memory access mode and therefore do not present any substantial difference in the speed of data access. 

More in detail, the differences between the two modes can be sought in their implementation:
Random Access can be realized directly via RAM memory wiring, while direct access can use secondary storage; in this case is obvious that random access is faster than direct access.