==how to use Drc to check the sch==
Open Command Port:
	Go to suitable path.
		- /tmp/laser_ctrl/........
	Then
In Command Port:
	Use
	- gnetlist -g drc2 -o MyDesign.drc MyDesign.sch 	
		-Directly check any unconnect nets or pins.
	Or	
	-gnetlist -g drc2 -l drc_rule.txt -o MyDesign.drc MyDesign.sch 
		- Checked  all drc problem without any defined in drc_rule.txt.