The 'ncsim' binary is the simulator used for VHDL and Verilog language. It can be installed from an "IUS" (Incisive Unified Simulator) stream, e.g. IUS6, IUS81 or IUS82. This is not only a simulator but also a parser. In the IC5141 stream the parser (and the simulator too I think) was part of the IC5141 stream, but for IC61x it is installed separately.
I hope this answers your question?