The DAS and AOSC backends wrote files in the GSD file format. GSD files contain lists of scalar and array data elements, prefaced by a prolog which describes the data and is used to retrieve it. The Starlink GSD library contains routines for accessing the data within GSD format files.
See GSD - Global Section Datafile System and The Global Section Datafile(GSD) access library for more details.
For a full list of scalar and array data stored in DAS and AOSC GSD files see the Appendix of this document.