Dump fsdb file using modelsim

just follow the below steps,
1)Copy X:\Novas\Debussy\share\PLI\modelsim_pli\WINNT\novas.dll to X:\modelsim\win32\

2)Edit X;\modelsim\modelsim.ini and modify the following lines,
Veriuser = novas.dll

and add the following lines into your testbench,

initial
begin
$fsdbDumpfile("test.fsdb");
$fsdbDumpvars(0,"usbf_top_tb");
$fsdbDumpflush;
end