B Glossary

Application – A piece of software which operates on data to produce some desired result.

C – A programming language used in some applications and libraries.

Extensions (or HDS extensions) – Components of an HDS (e.g. an NDF) file used to store additional information about data.

f77 – the Fortran 77 compiler command

f90 – the Fortran 90 compiler command

Fortran – The Starlink preferred language for applications programming.

Header – Information at the start of a file which describes the origins, components, and sometimes the history of the file.

HDS – The Hierarchical Data Structure file format. This allows many pieces of distinct information to be stored in one file. NDFs are an example of the HDS format.

IMG library – A simple library used to gain access to NDF files.

Interface file – A file which the ADAM system uses to find out information about the various parameters needed to use a code.

Monolith – A code which groups many applications together into a single package.

NDF – N-dimensional data format. This is a way of storing many different types of information in the same file. All Starlink Data Format files (.sdf files) are NDFs.

NDF library – A collection of routines used to access and manipulate all the various components of an NDF file.

Package – A larger piece of software consisting of many small applications.

Parameters – Items of information which the code needs to run. These are usually provided by the user.

Mapping – A way of describing the layout of an array within an NDF to the codes that manipulate them.

Quality array – An array of values associated with all the pixels in a file which report on the status of the pixel e.g. good/bad.

Starlink – The RAL-based organisation responsible for coordinating the UK astronomical computing effort.

Variance array – An array of values associated with all the pixels in a file which correspond to the squared standard deviation of the data value of those pixels.