Hu Yoshida

A History Lesson at Harvard

Blog Post created by Hu Yoshida Employee on Sep 11, 2015

Last week I took a few days of vacation with my wife and daughter in Boston. One afternoon we went to vist the Harvard campus in Cambridge. While looking for a restroom, I stumbled into the Science building where I found the first IBM computer, the Mark I, IBM Automatic Sequence Controlled Calculator (ASCC) sitting in the triangle core of the building. I was thrilled to see the first mainframe computer ever built.


It was conceived by Harvard Professor Dr. Howard Aiken and it was encased in a steel frame that was 51 feet long, 8 feet high and about 2 feet deep, built by IBM engineers in Endicott, N.Y. It was delivered to Harvard in August of 1944 in time to help with the calculations to develop the atom bomb. It was the worlds largest electromechanical calculator at the time. It was electromechanical in that the basic calculating units had to be synchronized mechanically, run by a 50-foot shaft driven by a five-horsepower electric motor.



An interesting side note in the display was this picture of an actual log entry of the first computer bug.




A description of the Mark I’s compute capability is extracted from wikipedia and presented below (

“The Mark I had 60 sets of 24 switches for manual data entry and could store 72 numbers, each 23 decimal digits long.[13]It could do three additions or subtractions in a second. A multiplication took six seconds, a division took 15.3 seconds, and a logarithm or a trigonometric function took over one minute.


The Mark I read its instructions from a 24-channel punched paper tape and executed the current instruction and then read in the next one. It had no conditional branch instruction. This meant that complex programs had to be physically long. A loop was accomplished by joining the end of the paper tape containing the program back to the beginning of the tape (literally creating a loop). This separation of data and instructions is known as the Harvard architecture (although the exact nature of this separation that makes a machine Harvard, rather than Von Neumann, has been obscured with the passage of time, see Modified Harvard architecture). “


By the 1950’s IBM had replaced the electromechanical computers with the first generation of electronic computers using vacumm tubes. In the 1960’s the second generation was introduced using transistors and magnetic core memories. In the late 1960’s the third generation computers introduced integrated circuits.


In comparison, storage has relied on mechanical electro magnetic devices for over 50 years and is just now transitioning to solid state devices. Flash is just the first generation of non-volatile memory devices. I believe that we will see an acceleration in non-volatile memory technology in the coming years. However, at the same time I expect to see mechanical electromagnetic devices like tape and disk stay around for some time to come.