4.3 The Extended XDR Layer
XDR is a standard for describing and encoding data and a library of
functions for external data representation, allowing programmers to
encode data structures in a machine-independent way. Classic or 64-bit
offset NetCDF employs an extended form of XDR for representing
information in the header part and the data parts. This extended XDR
is used to write portable data that can be read on any other machine
for which the library has been implemented.
The cost of using a canonical external representation for data varies
according to the type of data and whether the external form is the
same as the machine's native form for that type.
For some data types on some machines, the time required to convert
data to and from external form can be significant. The worst case is
reading or writing large arrays of floating-point data on a machine
that does not use IEEE floating-point as its native representation.
