This chapter briefly summarizes those properties of MIDAS [Crane et al.1985] that are important with respect to EXSAS. Some of them have already been mentioned above. For a thorough description of MIDAS the reader is referred to the relevant documentation prepared by the Image Processing Group at ESO (see appendix A) as there mainly are ESO Operating Manual No. 1 (MIDAS Volume A: System & Volume B: Data Reduction) and The MIDAS Environment.
The main features of MIDAS can be outlined as follows:
Standard interfaces for I/O access data stored in files with standard formats. Within MIDAS data files can be organized as tables or images (also called bulk data frames). Tables are used for storage of heterogeneous data while images are arrays containing numbers from a homogeneous set of data. The elements in a table are ordered in rows and columns. Columns are identified via their labels. Usually tables serve to store information from lists of data. Because of the fixed data formats all external software packages operating in the MIDAS environment are able to utilize the full range of MIDAS commands for data presentation (e.g. plotting) and manipulation (e.g. smoothing, fitting, statistical analysis). Thus the goal of creating an analysis system for X-ray data could be reduced to develop those packages which are not already existing in MIDAS.