A relative record data set (RRDS) is a type of

data set A data set (or dataset) is a collection of data. In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record of the d ...

organization used by IBM's VSAM computer data storage system. Records are accessed based on their ordinal position in the file (''relative record number'', RRN). 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 Random access (more precisely and more generally called direct access) is the ability to access an arbitrary element of a sequence in equal time or any datum from a population of addressable elements roughly as easily and efficiently as any othe ...

and dynamic access.

Structure

An RRDS consists of data records in sequence, with the record number indicating the record's logical position in the data set. A program can access records randomly using this positional number or access records sequentially. But unlike a

Key Sequenced Data Set A key-sequenced data set (KSDS) is a type of data set used by IBM's VSAM computer data storage system. Each record in a KSDS data file is embedded with a unique key. A KSDS consists of two parts, the data component and a separate index file kn ...

, an RRDS has no keys, so the program cannot access records by key value.

References

*https://web.archive.org/web/20051013071230/http://www.jaymoseley.com/hercules/vstutor/vstutor.htm *http://www.mvsforums.com/techfaqsvsam.html *https://web.archive.org/web/20070311021954/http://www.redbooks.ibm.com/redbooks/SG246105/wwhelp/wwhimpl/js/html/wwhelp.htm Computer file systems {{Compu-storage-stub

Structure

See also

References