Dear Sir, I would like to say thanks for your help first. And the previous problem is solved when "setenv MBK_CATA_LIB to $TOP/cells/padlib", but I find the /cells/ring doesn't exist. Now, would you help me to solve another problem? I have passed the stage "Gate Netlist Comparator" that is "lvx vst al core core" but I cannot finished the command "asimut core addaccu result". The screen shows: . . . Searching `a2_y` ... BEH : Compiling `a2_y.vbe` (Behaviour) ... Making GEX ... Searching pattern file : `addaccu` ... Restoring ... Linking ... Error 104 :input/output `vdde` doesn't exist Error 104 :input/output `vsse` doesn't exist cannot continue further more. Thanks in advance! Regards, Ray Cheung