A relative record data set (RRDS) is a type of data set organization used by IBM's VSAM computer data storage system.[1]: 5 Records are accessed based on their ordinal position in the file (relative record number, RRN).[1]: 29 For example, the desired record to be accessed might be the 42nd record in the file out of 999 total.
The concept of RRDS is similar to sequential access method, but it can access with data in random access and dynamic access.[clarification needed]