17-Feb-09: Friden EC-130 Display System

I recently received an EMail from Mr. Jack Bialik that contained some very interesting information about the development of the CRT-based display system that ended up being used in Friden’s first electronic calculator, the Friden EC-130. All of the information contained in this posting is from Mr. Bialik’s memories of a project he was involved in at Stanford Research Institute in the early 1960’s.

Mr. Bialik obtained his BSEE from University of Michigan in 1950. After graduating, he worked at Consolidated Vultee Aircraft Corp. (CONVAIR), where he was involved in development of a display system utliizing CONVAIR’s Charactron display tube technology. Joseph McNaney of CONVAIR invented the Charactron tube in 1949, but the production operations were later transfered to Stromberg-Carlson (S-C) by General Dynamics, the parent corporation of (among others) CONVAIR and S-C. In late 1955, Mr. Bialik left CONVAIR, and joined Stanford Research Institute (now known as SRI International), a non-profit research and development organization founded in Menlo Park, California, in 1949. The Old Calculator Museum wishes to thank Mr. Bialik for sharing his memories.

In the latter part of 1961, SRI was contacted by Friden Calculating Machine Company’s VP of Research and Development, Mr. Larry Robinson. Robinson requested a proposal from SRI’s Computer Lab to design and develop a prototype transistorized CRT-based numeric display system that could display four lines of 27 digits on a small CRT display. Friden’s stated intention then was to use the SRI’s research efforts as the basis for producing an electronic display for an electronic calculator that Friden was planning to build. Friden’s requirement for such a display for this calculator was defined by the desire for the machine to be able to display the entry register, the result register, and temporary registers used to hold intermediate results of calculations. Existing display methods (Nixie or Pixie tubes) would require way too much space, power, and expense in order to display a similar amount of data. The use of a CRT display would provide a much more compact and efficient means to display this quantity of information.

Mr. Bialik, and his immediate Supervisor, Milton B. Adams, wrote up a proposal for the project that Friden accepted. Work on the project began in late 1961. A five-man design team was put together, with Mr. Bialik as the Project Leader and architect; Dave Condon and Dale Masher performing design work (logic and circuit implementation); Don Ruder to develop a separate testing system to drive the display subsystem; and Bill Stephens to fabricate the designs.

In early 1962 , SRI delivered to Friden three hardware copies (and associated documentation) of an engineering prototype display system that met the requirements established by Friden.. The display system contained four plug-in circuit boards that contained all of the circuitry to implement the display system, including the high voltage drive for the CRT. The prototype units were packaged in an aluminum housing with a viewport that allowed the face of the CRT to be seen, as well as house the electronics and power supply for the display system. Also included in the deliverables was a “calculator simulator”, a device that would allow digits to be entered into a keyboard and displayed on the display subsystem. The simulator device provided a means to test and troubleshoot the display system, and also to demonstrate that it indeed operated. The calculator simulator device was not a calculator — it could not perform any arithmetic. It only provided a means for entry (via a keyboard); storage (via a small magnetic drum); and control logic (transistorized circuitry) that would provide a source of data for the display system to display. Along with the hardware, all of the design information, engineering notebooks, and any other data related to the project were turned over to Friden when the project was completed and signed off.

Along with all of the work on the project itself, a patent (US Patent #3430095) on the principles of the display system and the “calculator simulator” was filed. It isn’t clear if SRI drafted the patent application for the concepts of the display system on its own, or if this was part of the arrangement with Friden. What is known is that because the work done by SRI was an exclusive “CLIENT CONFIDENTIAL” contract with Friden, once the patent was approved (not until February of 1969), SRI assigned all rights to the patent to Friden Calculating Machine Co. The patent lists Mr. Bialik, Mr. Masher, and Mr. Stephens as the inventors, but makes no reference at all to Stanford Research Institute.

The display system worked as required, and Friden appeared pleased with the results. The design of the display system was used pretty much un-modified from its SRI-designed form in various calculator prototypes. An early prototype electronic calculator, patented by Friden (US Patent #3474238), was based on a magnetic drum memory system, very similar to that used in the “calculator simulator” developed by SRI. Diagrams and text in this patent are very similar to those listed in the patent for the display subsystem and “calculator simulator”. Later patents from Friden outlining design prototypes that led to the development of the EC-130 also used much of the material in the original patent with little changes.

Although more research needs to be done, it seems pretty clear that in the early stages of brainstorming their ideas for an electronic calculator, Friden grappled with issues relating to how they were going to display the working registers of the machine that they had envisioned. One of the early prototype calculator patents filed by Friden indicated that it was considered very important that the calculator be able to display all of its working registers for the operator to see. As a result of this requirement, and limitations with existing numeric display technology, Friden had to look outside the company for design expertise in display systems technology. While it’s clear that Friden had internal resources skilled in the art of digital design, perhaps the “analog-ness” of the design requirements to generate a CRT-based numeric display required skillsets that didn’t exist in-house., This is probably why Stanford Research Institute’s Computer Lab was hired to do the design.

While the development of the display technology certainly played a significant role in making the EC-130 an early reality, the display system was only a part of what was needed to make a complete electronic calculator. It appears that much of the display system concept developed at SRI, along with some concepts from the “calculator simulator” (including basic transistorized logic gate designs) were used by Friden in the development of the EC-130. However, clearly the internal design work that went on at Friden to put the “brains” behind the display system was by far a more challenging task.

This commentary is in no way intended to take away any of the significance of Friden’s engineering effort in the development of the EC-130. It is, however, an interesting new tidbit of inforamation to add to the story of the development of Friden’s first electronic calculator.


One Response to “17-Feb-09: Friden EC-130 Display System”

  1. Mike Henderson Says:

    Thank you for the EC130 article. I loved playing with the pots that adjusted the dimensions of the various stroke graphics. My (young) co-worker asked how much they cost and I had no answer. This would be a good thing to add; especially with a reference to the price of a car made at the same time.

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