HP-35 RPN Calculator

When Jack K. Williams became President of Texas A&M University in 1970, he made the following statement:

I believe that during the years ahead we will be witness to a geometric rise in the development and adoption of innovative techniques and programs. In matters large and small, the atmosphere of education is heavy with the smell of change. For some of us this is a heady perfume; for others it is the pungent odour of brimstone. Either we sail the strange sea, benefited by whatever navigational experience we have and can command, or we will become passengers on educational vessels whose rudders are managed by others...*

When I arrived at Texas A&M, engineers had been using slide rules for more than a century. As a freshman engineering student, I even had to spend part of the introductory course learning how to operate one!

For my part I came with an HP-35 calculator, similar to one shown at the right. Before same Jack K. Williams handed me my diploma, HP-35's and calculators like it had swept away the slide rules. Today calculators that do the same work and more of the HP-35 (which retailed for US$395 in the early 1970's) can be found in virtually any drug store for US$10 or less.

Change is something that people find hard to deal with but cannot be stopped. Today computer code that was once resident on large mainframe computers can be found on web servers, running it with ease (click here for an example.) However, every now and then even the most addicted fanatics to new technology want to stop and play around with the "old stuff." When I came upon this nice JavaScript simulator, I could not resist it. Even pressing the mouse button while positioning the cursor over the keys brought back memories of punching those rugged buttons HP was justifiably known for.

God has a sense of humour; after a great experience at Texas A&M, I moved to Dallas to work for HP's rival in the calculator business, Texas Instruments. It is our hope that this page will bring back happy memories--or at least afford you an online calculator when you need it. (A copy of the instructions on the back of the HP-35 is shown at the left.)

Note: some browsers (like some versions of Safari) do strange things with JavaScript. JavaScript is also more prone to round-off error than the original. Try some simple test calculations first. Use at your own risk -- see the terms and conditions for more details! If you'd like this for your own website, you can click here and download it. It also works on an iPhone as well.

*From Dethloff, Harry C., A Pictorial History of Texas A&M University, 1876-1976. College Station, Texas: Texas A&M University Press, 1975.

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