Random access refers to the ability to access data at random. The opposite of random access is sequential access. To go from point A to point Z in a sequential-access system, you must pass through all intervening points. In a random-access system, you can jump directly to point Z. Disks are random access media, whereas tapes are sequential access media.
Random and Sequential Describe Data Files
The terms random access and sequential access are often used to describe data files. A random-access data file enables you to read or writeinformation anywhere in the file. In a sequential-access file, you can only read and write information sequentially, starting from the beginning of the file.
Both types of files have advantages and disadvantages. If you are always accessing information in the same order, a sequential-access file is faster. If you tend to access information randomly, random access is better.
Random access is sometimes called direct access.