A remarkably new patent on 1971 TI calculator technology

[brouhaha]

I just discovered US patent 6,650,317 B1, "Variable Function Programmed Calculator", for inventors Gary W Boone and Michael J Cochran, assigned to Texas Intruments, issued 2003-11-18, based on an application filed on 1995-01-05, which is thre result of a very long chain of application continuations going back to application 05/163,565, filed 1971-07-19. The patent cites as a preferred embodiment the TMS 1802.

A better known patent with the same title, inventors, and original application is US 4,074,351, granted 1978-02-14.

The main body of the '317 patent has the same content as the '351 patent, but hte drawings and listings have been "remastered". They're easier to read, but I'd worry that errors could have been introduced.

The claims of the '317 patent are centered around "preventing malfunction of key switch encoding", which was not covered in the '351 patent.

It is amazing that TI pursued this patent for so many years, although I suppose for a company of their size, the cost is inconsequential. It is unclear whether this patent will have any practical effect. Its claims might cover the way the HP-28S, 17B, 17BII, and 42S shared the memory address with the keyboard scanning, but given that HP no longer makes those, there is no cause for action.

[EdS2]

That is a remarkable chain - I can only suppose some of TI's current offerings (as of 2003, perhaps) are covered by it, which helps them keep their strong position.