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Origins of Architecture and Design of the IBM 1401

Late 1950's Enabling and Disruptive Technologies
for the IBM 1401

This page started April 2009, about 5 years after this IBM 1401 restoration project started :-((

Table of Contents

  • Introduction
  • An expanding list of major technologies in the IBM 1401
    - probably to be expanded until fatigue overcomes -
    I presume organization, alphbetical order, sub-lists will become advisable :-(( :-))
  • Further Readings

An Introduction

An unkind or irreverent person might equate engineering work to small boys playing with "Tinker Toys", occasionally searching the Tinker Toy (or Erector Set) box for a piece with useful characteristics to complete the object. Maybe going so far as to saw or whittle and/or glue a piece to do the job.

This view may seem harsh - but the fact remains that engineers need/use a great deal of existing technology to "create".

  • Given firecracker powder, with out metal, a gun or cannon is impractical.
  • Until the "modern" amplifying vacuum tube (created in part to fill a void ;-)) and/or semi-conductor was developed, radio and TV as we know it are "almost" impossible. (I'm sneaking that "almost" in there as some folks say "never say never". ;-))

One can write whole books about "enabling technologies" and "disruptive technologies", which engineers may select and/or enhance to accomplish their task.

This page looks for/at the "enabling technologies" (useful tinker-toy parts) related to the development of a cost effective IBM 1401 system. The cost of transistors and also core memory was falling enough to permit creation of a rather general purpose computer system to replace a generation of specialized punched card machines.

An overly brief difference between a physical scientist and an engineer (both being somewhat technical):

  • A scientist is more focused on concept, make one work once, get data, cost and reliability not that vital.
  • An engineer is more focused on cost, manufacterablilty, reliability, maintainability, human interface.
    Please don't throw rocks at me, I mean well -


  • Scientists can hit it big - a valuable Nobel prize, but most are low profile.
  • Engineers can hit it big - Edison, Noyce, but most are hidden by their employers.

    Quite a number of "enabling technologies", some "disruptive", were used in the IBM 1401 system ranging from a long standing IBM expertise with reading and punching punched cards utilized and enhanced in to 1402 Card Reader Punch - through transistors, circuit sets, SMS cards, electronic packaging, core memory, ... into the 1401 processor.

  • Card Reading and Punching Technology

    Transistor Technology

    from David Laws of CHM - about forming oxides on a transistor
    It sounds like the oxide masking technique developed at Bell Labs in early 1955 and patented in 1956.

    See the Silicon Engine at:

    David Laws

    from Joseph Logue -jclogue at msn dot com> - SMS cards

    04/23/2009 09:57 AM Hi Robert,

    Thanks for the invitation to join Rick and yourself in co-authoring the wealth of info about Ge transistor technology at the time of the development of the 1401.

    In 1953 Ralph Palmer asked me to educate 28 engineers from both Poughkeepsie and Endicott on the theory and practice of transistor circuits. I recommended that three of the six machines that were assigned as laboratory exercises be built. The Endicott engineers that graduated from "Logue's College of Digital Knowledge" were undoubtedly involved in the development of the 1401 but I do not know this as a fact. By 1954 I was convinced that Silicon was the semiconductor of the future and lost interest in Germanium. I therefore am not the right person to be a co-author.


    Crandall, Don - DonC at jtech dot com

    "... Aug 28, 1959 Lab Newsletter which features the Transistor Tester that I designed and built in 1958. All 40,000 transistors in the first 3 1410 computers were 100 % tested on this machine with the data automatically punched into card decks by a connected 526 Summary Punch. According to Joe Diute, our department financial guy at that time, this machine paid for itself ($30,000) in the first 3 months of operation because of the manual manpower saved. "
    Warning - the full sized versions below are about 200 K bytes each

    Circuit Set and SMS Card Technology

    from Joseph Logue - jclogue at msn dot com> - SMS cards
    04/26/2009 01:01 PM Robert,

    You are correct that the boards that my group designed and had built were the progenitors of the SMS cards. Also Ralph Palmer put me in charge of transistor circuit standardization for all IBM transistorized machines. I also pushed for alloy-junction transistors over point contact transistors.

    In addition, having seen the wire wrap invented by Bell Labs I adopted wire wrap for the back panel connections for the SMS program.

    I would be glad to edit a page or two of what you would care to write.


    Core Memory Technology

    Schematic Automation, CAD/CAE

    Magnetic Tape Technology

    Printer Technology

    Computer Packaging Technology

    Further Readings

    for comments and suggestions, please
    email Ed Thelen