  We present SSD, Software for Systems with Delays, a de novo MATLAB package
for the analysis and model reduction of retarded time delay systems (RTDS).
Underneath, our delay system object bridges RTDS representation and Linear
Fractional Transformation (LFT) representation of MATLAB. This allows seamless
use of many available visualizations of MATLAB. In addition, we implemented a
set of key functionalities such as H2 norm and system gramian computations,
balanced realization and reduction by direct integral definitions and utilizing
sparse computation. As a theoretical contribution, we extend the
frequency-limited balanced reduction to delay systems first time, propose a
computational algorithm and give its implementation. We collected two sets of
benchmark problems on H2 norm computation and model reduction. SSD is publicly
available in GitHub at https://github.com/gumussoysuat/ssd. Our reproducible
paper and two benchmark collections are shared as executable notebooks.
