VMX asserted infringement first with IBM , AT&T and then Wang .
All three companies reportedly would have been able to invalidate the patent on the basis of prior art and their licenses from Sudbury Systems Inc , for their Kolodny and Hughes patent ( see above ) .
VMX asserted infringement first with IBM , AT&T and then Wang , but all three companies reportedly would have been able to invalidate the patent on the basis of prior art and their licenses from Sudbury Systems Inc , for their Kolodny and Hughes patent ( see above ) .