What are the differences between ESDS, KSDS, and RRDS in VSAM?

VSAM (Virtual Storage Access Method) is a type of file system used in mainframe computers. There are three types of datasets in VSAM, each with its own characteristics:

1. ESDS (Entry-Sequenced Data Set): ESDS is a sequential dataset where records are added at the end of the dataset in the order in which they are written. It is suitable for applications that require fast sequential access to large volumes of data.
2. KSDS (Key-Sequenced Data Set): KSDS is an indexed dataset where records are accessed based on a key value. This type of dataset is ideal for applications that require fast random access to individual records.
3. RRDS (Relative Record Data Set): RRDS is a dataset where records are accessed based on their relative position within the dataset. This type of dataset is useful for applications that require direct access to specific records based on their relative position.

Overall, the main differences between ESDS, KSDS, and RRDS in VSAM lie in their access methods and suitability for different types of applications.