1st Computer – ENIAC Database (Part 2)

1st Computer – ENIAC  continue:-


The Universal Automatic Computer or UNIVAC was a computer milestone achieved by Dr. Presper Eckert and Dr. John Mauchly, the team that invented the ENIAC

The Universal Automatic Computer or UNIVAC was a computer milestone achieved by Dr. Presper Eckert and Dr. John Mauchly, the team that invented the ENIAC


The completed machine (ENIAC) was announced to the public the evening of February 14, 1946 and formally dedicated the next day at the University of Pennsylvania. The original contract amount was $61,700; the final cost was almost $500,000 (approximately $6,100,000 today). It was formally accepted by the U.S. Army Ordnance Corps in July 1946. ENIAC was shut down on November 9, 1946 for a refurbishment and a memory upgrade, and was transferred to Aberdeen Proving GroundMaryland in 1947. There, on July 29, 1947, it was turned on and was in continuous operation until 11:45 p.m. on October 2, 1955.


Johannes Blobel and Dr Jochen Viehoff, director of the Heinz-Nixdorf MuseumsForum, with the rebuilt panel from the Eniac.

Johannes Blobel and Dr Jochen Viehoff, director of the Heinz-Nixdorf MuseumsForum, with the rebuilt panel from the Eniac.

Role in the development of EDVAC

A few months after ENIAC’s unveiling in the summer of 1946, as part of “an extraordinary effort to jump-start research in the field”, the Pentagon invited “the top people in electronics and mathematics from the United States and Great Britain” to a series of forty-eight lectures given in Philadelphia, Pennsylvania; all together called The Theory and Techniques for Design of Digital Computers—more often named the Moore School Lectures. Half of these lectures were given by the inventors of ENIAC.

ENIAC was a one-of-a-kind design and was never repeated. The freeze on design in 1943 meant that the computer design would lack some innovations that soon became well-developed, notably the ability to store a program. Eckert and Mauchly started work on a new design, to be later called the EDVAC, which would be both simpler and more powerful. In particular, in 1944 Eckert wrote his description of a memory unit (the mercury delay line) which would hold both the data and the program. John von Neumann, who was consulting for the Moore School on the EDVAC, sat in on the Moore School meetings at which the stored program concept was elaborated. Von Neumann wrote up an incomplete set of notes (First Draft of a Report on the EDVAC) which were intended to be used as an internal memorandum—describing, elaborating, and couching in formal logical language the ideas developed in the meetings. ENIAC administrator and security officer Herman Goldstine distributed copies of this First Draft to a number of government and educational institutions, spurring widespread interest in the construction of a new generation of electronic computing machines, including Electronic Delay Storage Automatic Calculator (EDSAC) at Cambridge University, England and SEAC at the U.S. Bureau of Standards.


1st Computer - ENIAC

1st Computer – ENIAC


Later Improvements

A number of improvements were made to ENIAC after 1948, including a primitive read-only stored programming mechanism using the Function Tables as program ROM, an idea included in the ENIAC patent and proposed independently by Dr. Richard Clippinger of BRL. Clippinger consulted with von Neumann on what instruction set to implement. Clippinger had thought of a 3-address architecture while von Neumann proposed a 1-address architecture because it was simpler to implement. Three digits of one accumulator (6) were used as the program counter, another accumulator (15) was used as the main accumulator, a third accumulator (8) was used as the address pointer for reading data from the function tables, and most of the other accumulators (1–5, 7, 9–14, 17–19) were used for data memory.

The programming of the stored program for ENIAC was done by Betty Jennings, Clippinger and Adele Goldstine. It was first demonstrated as a stored-program computer on September 16, 1948, running a program by Adele Goldstine for John von Neumann. This modification reduced the speed of ENIAC by a factor of six and eliminated the ability of parallel computation, but as it also reduced the reprogramming time to hours instead of days, it was considered well worth the loss of performance. Also analysis had shown that due to differences between the electronic speed of computation and the electromechanical speed of input/output, almost any real-world problem was completely I/O bound, even without making use of the original machine’s parallelism. Most computations would still be I/O bound, even after the speed reduction imposed by this modification.

Early in 1952, a high-speed shifter was added, which improved the speed for shifting by a factor of five. In July 1953, a 100-word expansion core memory was added to the system, using binary coded decimalexcess-3 number representation. To support this expansion memory, ENIAC was equipped with a new Function Table selector, a memory address selector, pulse-shaping circuits, and three new orders were added to the programming mechanism.


1st Computer - ENIAC

1st Computer – ENIAC


Why ENIAC was better than other early computers?

Mechanical and electrical computing machines have been around since the 19th century, but the 1930s and 1940s are considered the beginning of the modern computer era.

ENIAC was, like the Z3 and Harvard Mark I, able to run an arbitrary sequence of mathematical operations, but did not read them from a tape. Like the Colossus, it was programmed by plugboard and switches. ENIAC combined full, Turing complete programmability with electronic speed. The Atanasoff–Berry Computer (ABC), ENIAC, and Colossus all used thermionic valves (vacuum tubes). ENIAC’s registers performed decimal arithmetic, rather than binary arithmetic like the Z3, the ABC and Colossus.

Like the Colossus, ENIAC required rewiring to reprogram until September 1948. Three months earlier, in June 1948, the Manchester Small-Scale Experimental Machine (SSEM) ran its first program and earned the distinction of first stored-program computer. Though the idea of a stored-program computer with combined memory for program and data was conceived during the development of ENIAC, it was not initially implemented in ENIAC because World War II priorities required the machine to be completed quickly, and ENIAC’s 20 storage locations would be too small to hold data and programs.

Public Knowledge

The Z3 and Colossus were developed independently of each other, and of the ABC and ENIAC during World War II. The Z3 was destroyed by the Allied bombing raids of Berlin in 1943. The ten Colossus machines were part of the UK’s war effort. Their existence only became generally known in the 1970s, though knowledge of their capabilities remained among their UK staff and invited Americans. All but two of the machines were dismantled in 1945; the remaining two were used in GCHQ until the 1960s. Work on the ABC at Iowa State University was stopped in 1942 after John Atanasoff was called to Washington, D.C., to do physics research for the U.S. Navy, and it was subsequently dismantled.

ENIAC, by contrast, was put through its paces for the press in 1946, “and captured the world’s imagination”. Older histories of computing may therefore not be comprehensive in their coverage and analysis of this period. As the Colossus was used to decrypt Russian messages up until the 1960s, it was kept confidential for almost 40 years, only becoming public knowledge in the late 1970s.


1st Computer - ENIAC

1st Computer – ENIAC



For a variety of reasons (including Mauchly’s June 1941 examination of the Atanasoff–Berry Computer, prototyped in 1939 by John Atanasoff and Clifford Berry), U.S. Patent 3,120,606 for ENIAC, applied for in 1947 and granted in 1964, was voided by the 1973 decision of the landmark federal court case Honeywell v. Sperry Rand, putting the invention of the electronic digital computer in the public domain and providing legal recognition to Atanasoff as the inventor of the first electronic digital computer.

Pieces of ENIAC are held by the following institutions:


ENIAC Programmers Project

ENIAC Programmers Project

Famous ENIAC

ENIAC was named an IEEE Milestone in 1987.

In 1996, in honor of the ENIAC’s 50th anniversary, The University of Pennsylvania sponsored a project named, “ENIAC-on-a-Chip“, where a very small silicon computer chip measuring 7.44 mm by 5.29 mm was built with the same functionality as ENIAC. Although this 20 MHz chip was many times faster than ENIAC, it had but a fraction of the speed of its contemporary microprocessors in the late 1990s.

In 1997, the six women who did most of the programming of ENIAC were inducted into the Women in Technology International Hall of Fame. The role of the ENIAC programmers is treated in a 2010 documentary film titled Top Secret Rosies: The Female “Computers” of WWII by LeAnn Erickson. A 2014 documentary short, The Computers by Kate McMahon, tells of the story of the six programmers; this was the result of 20 years’ research by Kathryn Kleiman and her team as part of the ENIAC Programmers Project.

In 2011, to honor of the 65th anniversary of the ENIAC’s unveiling, the city of Philadelphia declared February 15 as ENIAC Day.

The ENIAC celebrated its 70th anniversary on February 15, 2016.

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