This note describes the design of the CTD-SLT software. The pattern recognition and parameter determination algorithms run in a network of transputers on the CTD readout controller (ROC) boards. These algorithms are coded in the transputer's native programing language, occam. The program structure, data flow, control, data formats, and monitoring are described here. Details of the algorithms [1, 2], readout and trigger architectures [3], and simulation and estimated performance [4] have been previously described.