The DDJ logo, here only for decorative purposes. Dr. Dobb's Journal September, 1997
by Mark Nelson

The past 10 years have seen a big change in the way programmers view the US Patent system. We’ve moved from our long-standing position of blissful ignorance into a keen awareness that each and every line of code we write just might step on the toes of an existing software patent. Times have certainly changed.

Back in 1991, when software patents were first starting to make inroads into the public awareness, I hosted a panel discussion at the Software Development Conference. DDJ Editor-in-chief Jon Erickson , one of the round table participants, gave a recap of the discussion in his Editorial of April, 1991.

One key suggestion that came up in the panel was that the computer science industry get a chance to review software patents before they were issued. The current US patent system doesn’t make patent applications public until the patent is actually issued, which in some cases can take decades.

This lengthy delay between application and issuance of a patent can result in the so-called submarine patent. A submarine patent is one that hides in the patent office for years, emerging after a particular technique has come into common practice. This can result in enormous economic benefit to the holder of the patent, making it often desirable to delay the journey of your patent application through the PTO.

The classic example of this is US Patent 4,942,516 , “Single-chip integrated-circuit computer architecture”, issued to Gilbert Hyatt in 1990. This patent apparently gave full rights to the concept of the single chip microcomputer to Gilbert Hyatt, who was up until then a non-entity in the annals of the microprocessor. This patent apparently took 20 years to work its way through the system, long enough to build a multi-billion dollar business full of captive licensees! (Texas Instruments succeeded in having the Hyatt patent overturned in 1996, but this is still subject to appeal.)

Submarine Warfare

Relief for US industry seems to be on the near horizon. House bill 400 of the 105th Congress seeks to make several key modifications to the patent system. The proposed changes include:

  • Patent applications still active 18 months after submission will be made available to the public.
  • Commercial use of a given technology one year or more prior to any patent application would constitute a valid defense against infringement. (This means that if your trade secret is outed by someone else’s patent, you shouldn’t have to pay royalties.)
  • Delays in the processing of a patent that are caused by the Patent Office will not count against the lifetime of the patent. (Normal patent lifetime is 20 years from the time of filing. Until 1995 patent lifetime began when the patent was issued.)

This bill has vast implications for a fast evolving industry such as ours. It has already been passed by the House, and should make it to the floor of the Senate by the end of the year. Fortunately, we all have time to review the bill and comment to our legislators. Information on the bill, including full text and digest versions, is available on, the Library of Congress’s Legislative Information Web site.

To find out more about this bill, read the text on Thomas . If this link has aged and no longer works, you can search for it using either its name, “21st Century Patent System Improvement Act”, or number, “H.R. 400.” What you do after that is up to you.