Why and where we use External Data Representation (XDR) ?

Why and where we use External Data Representation (XDR) ?

XDR not only solves data portability problems, it also permits the reading and writing of arbitrary C language constructs in a consistent and well-documented manner. Therefore, it makes sense to use the XDR library routines even when the data is not shared among machines on a network.

The XDR standard does not depend on machine languages, manufacturers, operating systems, or architectures. This condition enables networked computers to share data regardless of the machine on which the data is produced or consumed. The XDR language permits transfer of data between different computer architectures and has been used to communicate data between such diverse machines as the VAX, IBM®, and Cray.

Remote Procedure Call (RPC) uses XDR to establish uniform representations for data types in order to transfer message data between machines. For basic data types, such as integers and strings, XDR provides filter primitives that serialize, or translate, information from the local host’s representation to XDR’s representation. Likewise, XDR filter primitives deserialize XDR’s data representation to the local host’s data representation. XDR constructor primitives allow the use of the basic data types to create more complex data types such as arrays and discriminated unions.