ESDS files store records in the order they were added to the dataset. The records are referenced by their physical address, also known as RBA (Relative Byte Address). Assuming we have 60 bytes per record in an ESDS dataset, then RBA of the 1st record would be 0, RBA of the 2nd record would be 60, RBA of the 3rd record would be 120, and so on. RBA allows for sequential access to records, known as addressed access. The data is stored in the order in which it was entered. New records are added at the end. Records cannot be deleted from the ESDS dataset, but they may be marked as inactive. ESDS dataset records can be of variable or fixed length.
