Facilities are provided by the AST library for performing input and output (I/O) with any kind of Object. This means it is possible to write any Object into various external representations for storage, and then to read these representations back in, so as to restore the original Object. Typically, an Object would be written by one program and read back in by another.
We refer to ``external representations'' in the plural because AST is designed to function independently of any particular data storage system. This means that Objects may need converting into a number of different external representations in order to be compatible with (say) the astronomical data storage system in which they will reside.
In this section, we discuss the basic I/O facilities which support
external representations based on text. These are implemented using a
new kind of Object--a Channel. We will examine later how
to use other representations, based on FITS headers, for storing
Objects. These are implemented using a more specialised form of
Channel called a FitsChan ().
AST A Library for Handling World Coordinate Systems in Astronomy