Design Rule Checking Kudos to the guy who first thought of, and implemented "DRC". It works very well right up to the time a designer produces gerber files. But after that, we're on our own. I understand that some Fab shops have the capability to run a DRC against the customer supplied gerber files. Sometimes spacing errors are found. But how could this be? Are cad operators not paying attention to their post-processing reports? or are they changing apertures during the gerber process? or are Fab shops changing aperture sizes and then running DRC's? I would be happy to run a DRC against my gerber files, but I have yet to see a cad system that can do it. We can simulate the artwork-select a .001 grid- and then view the simulation. But this is error prone and could make you go blind. Does software exist for a dos/unix system to run a DRC against the gerber files? I don't care about neat graphics, just a program that will allow me to check proper spacing of artwork features. Al Slagle [log in to unmask]