Just start learn using ModelSim-Altera for simulation

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When Quartus writes out a post-synthesis netlist, that netlist contains device specific VHDL or Verilog models so that Modelsim can simulate the netlist. Its those models that are contained in those libraries, and that is why the libraries are named after devices.

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Thanks very much, Dave. So If I use ModelSim PE instead of ModelSim-Altera, there will be no libraries for Altera's devices in ModelSim. I need to load the libraries by myself, right? Sorry to ask these stupid questions:(