This chapter describes briefly the off-line data analysis software, developed to satisfy the data analysis needs for debugging the GMRT as well as for developing new algorithms for calibration and imaging at low frequencies. A modular, hierarchical software environment was therefore developed over the course of this dissertation. This software system is organized in the form of general purpose libraries at the lowest layer and a suit of general purpose application programs at the top-most layer. This design required much extra work, but it was perceived to be well worth the effort with the hope that ultimately, at the highest software layer, a large number of programmers would be professional astronomers writing complicated (but interesting) numerical analysis code.
The entire software now constitutes in excess of 50,000 lines of C++ code and in excess of 10,000 lines of C and FORTRAN code. Some others in the GMRT group have used these general purpose tools to write more software. In a software development cycle, the number of bug reports per unit of time (week or month) is generally considered to be an indicator of the stability of the software. Assuming this to be a good measure, the libraries are now well debugged and stable (however, a low rate of bug reports could also be due to lack of sufficient number of careful users).