ENIAC U. S. Army
Aberdeen Proving Ground, MD
This historical monograph covers the pioneer efforts and subsequent contributions of the U.S. Army Ordnance Corps in the field of automatic electronic computing systems during the period 1942 through 1961.
No comprehensive history of electronic computers within the U.S. Army Ordnance Corps had previously been compiled and for this reason the sources for this monograph were many and varied. In general, however, these sources consisted of books (i.e., open literature), computer manuals, reports, interviews, and data prepared especially for this monograph by personnel of the Computing Laboratory, Ballistic Research Laboratory, Aberdeen Proving Ground, MD.
Mr. Martin H. Weik, Technical Staff Assistant, Computing Laboratory, BRL, assisted the author during the entire course of preparation of the monograph and supplied much of the information used in its compilation. Mr. Weik also prepared The Computer Tree which is included in Chapter VII.
CHAPTER I - PRE-ELECTRONIC COMPUTING DEVICES
CHAPTER II - ENIAC
CHAPTER III - EDVAC
CHAPTER IV - ORDVAC
CHAPTER V - BRLESC
CHAPTER VI - COMPUTERS FOR SOLVING GUNNERY PROBLEMS
CHAPTER VII - THE COMPUTER TREE
APPENDIX I - TECHNICAL DATA OF ENIAC FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX II - TECHNICAL DATA OF EDVAC FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX III - TECHNICAL DATA OF ORDVAC FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX IV - TECHNICAL DATA OF BRLESC FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX V - INVENTORY OF COMPUTERS WITHIN THE U.S. ARMY ORDNANCE CORPS - FY 1961
APPENDIX VI - ARITHMETIC OPERATION TIME (INCLUDING ACCESS) OF COMPUTING SYSTEMS FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX VII - APPROXIMATE COST OF COMPUTING SYSTEMS (BASIC OR TYPICAL SYSTEMS) FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX VIII - GLOSSARY OF COMPUTER ENGINEERING AND PROGRAMMING TERMINOLOGY FROM BRL REPORT NO. 1115, MARCH 1961
APPENDIX IX - BIBLIOGRAPHY
It is quite well known that the United States Army Ordnance Corps has made many significant contributions to both science and industry. Of all its contributions however, few can match the importance of the Ordnance Corps' pioneer efforts in the field of electronic computers. In the interest of national defense, the development of electronic computing systems could not wait until normal economic laws brought about the supply of systems through commercial demand. Therefore, recognizing the urgent need for such computers, the Ordnance Corps initiated the development work and supplied the funds that led to the first high-speed, electronic, automatic computer. This computer, called the ENIAC (Electronic Numerical Integrator And Computer), was proposed in 1942 and completed in 1946.
The installation of the ENIAC in 1947 in the Ballistic Research Laboratory at Aberdeen Proving Ground, MD, marked the beginning of the widespread use of electronic computing machines. Since the advent of the ENIAC, a large expansion has taken place in the computer field. Investment rates in computing equipment in the United States rose from ten million dollars per year in 1953 to one hundred million dollars per year in 1956. Present (1961) expenditures for computing equipment has passed the billion dollars per year mark.
Electronic computers find wide use throughout the Department of Defense and many other government agencies. Almost every commodity industry such as oil, steel, and rubber is utilizing computing equipment for both scientific and commercial applications. Service industries, such as banking, transportation, and insurance have applied large scale computing systems toward the solution of problems in the fields of accounting, reservations control, and bookkeeping. Manufacturers have used computing systems for design engineering and scientific research. Many systems are being utilized for inventory and stock control. The determination of manufacturing plant location and stock parts storage are being made by linear programming methods. Electronic computers are used by the construction industry for design and location of structures and road nets. Many digital computers form a part of closed loop industrial process control systems. Where the processing of large quantities of data are necessary, computing systems are invaluable.
It must be left for the historian of the future to accurately evaluate the effect of automatic computing machines on man's destiny. It is yet too early to make even a good guess. However, one thing is certain: electronic computers have ushered in a change equal to that of the Industrial Revolution. By the harnessing of mechanical power (steam engine, etc.) man was able to perform work beyond the capacity of his own muscles (or that of beasts of burden) and his world changed as a result. He could travel at speeds undreamed of in earlier times, he could fabricate structures never before possible, and he could build machinery to perform intricate work and produce large quantities of consumer goods at low cost. By the development of machinery for handling information and thus enabling decisions to be made automatically by mechanizing the logic of mental process, man is now able to perform mental work beyond the capacity of his brain. Many problems that have remained unsolved for years because the calculations were too formidable for a human to perform can now be handled by electronic computers. Aircraft design, ballistic crystallography, electron optics, astronomy, pure mathematics, and weather forecasting are just a few of the activities in which automatic computing machines are and will continue to play ever increasingly important roles.
At this point it might be well to consider the question: "What is an automatic computer?" An automatic computer is a machine so constructed that it can perform a complicated sequence of arithmetical and logical operations at high speeds, without human intervention or assistance. The present-day automatic computers utilize electronic circuits as the major operating components and are capable of computing speeds of the order of a few millimicroseconds per logical decision. We can properly refer to this class of machines as high-speed electronic automatic computers.
It is the term "automatic," however, that designates the most important characteristic of the modern electronic computer. This is its ability to guide and control itself during the course of its data processing action. The human operator is needed only to set up and start the machine, which can then operate without human intervention, guidance, or direction. However, the machine is self-directing only within definite prescribed limits which must be predetermined by the operator during the setup of the machine and during programming.
Automatic computers perform many operations which previously were done only by human labor and this has led some writers to refer to automatic computers as "giant brains." They definitely are not electronic brains and do not "think" in the creative sense of the word. A human mind must first determine a way of solving the problem and then instruct the computer how to solve the problem when given the data. The human operation of preparing the instructions for the automatic computer is called programming, and the resulting set of instructions is called a program or a routine. Without a program, an automatic computer cannot perform any data processing.
All computers, whether mechanical or electronic, can be divided into two distinct classes, depending on the form in which information is handled. If the information is handled in the form of letters or digits they are classed as digital computers. If the information is handled in the form of an electrical equivalent of physical variables, they are classed as analog computers. Analog computers may also represent numerical quantities by such physical variables as translation, rotation, voltage, or resistance. The slide rule and the antiaircraft predictor are examples of analog computers. The digital computer utilizes numbers in a given scale of notation to represent all the quantities that occur in a problem or a calculation. The abacus and the desk calculator are examples of digital computers.
In a very general way it can be said that the advantages of the digital computer compared to the analog computer, are its greater flexibility and greater precision, while its disadvantages are its higher cost and greater complexity.
More and more emphasis is being placed on the digital computer although there are still some applications where the analog computer is desirable. Throughout the Ordnance Corps the digital computer is the one most widely used for the various Ordnance applications. The analog computer finds use primarily in the older antiaircraft and antimissile fire control devices.
The importance of automatic computers to the U.S. Army Ordnance Corps is well illustrated by the extensive used of various types of computers at Ordnance Corps installations. An inventory of computers within the Ordnance Corps for the Fiscal Year 1961 lists a total of 112 computers of 36 different types in use at 26 Ordnance Corps installations. (See Appendix V ).
At Aberdeen Proving Ground, for example, the Computing Laboratory has a personnel strength representing 12% of the total personnel of the Ballistic Research Laboratory. The Computing Laboratory employs 122 persons. These include: 51 Mathematicians; 15 Electronics Engineers; 4 Tabulating Equipment Operators; 38 Maintenance and Supporting personnel; and 14 military.
This document has been rendered machine readable thanks to the typing efforts of Monique Nguyen, LB&B. monique@ARL.MIL