The BRLESC I ( Ballistic Research Laboratories Electronic Scientific Computer ) was a first-generation electronic computer built by the United States Army's Ballistics Research Laboratory ( BRL ) at Aberdeen Proving Ground with assistance from the National Institute of Standards and Technology ( NIST ), and was designed to take over the computational workload of EDVAC and ORDVAC, which themselves were successors of ENIAC.

The meaning of the acronym is unknown, but mid-century, high-technology names often ended in " AC " ( generally for " Automatic Computer " or similar ), such as ENIAC, Univac, EDVAC, MANIAC, and JOHNNIAC.

The ACE implemented subroutine calls, whereas the EDVAC did not, and what also set the ACE apart from the EDVAC was the use of Abbreviated Computer Instructions, an early form of programming language.

It was not a Turing complete computer, which distinguishes it from more general machines, like contemporary Konrad Zuse's Z3 ( 1941 ), or later machines like the 1946 ENIAC, 1949 EDVAC, the University of Manchester designs, or Alan Turing's post-War designs at NPL and elsewhere.

On June 30, 1945, before ENIAC was made, mathematician John von Neumann distributed the paper entitled First Draft of a Report on the EDVAC.

EDVAC was designed to perform a certain number of instructions ( or operations ) of various types.

The so-called Harvard architecture of the Harvard Mark I, which was completed before EDVAC, also utilized a stored-program design using punched paper tape rather than electronic memory.

The machine, having been inspired by John von Neumann's seminal First Draft of a Report on the EDVAC, was constructed by Maurice Wilkes and his team at the University of Cambridge Mathematical Laboratory in England.

The third stream of computer development was Eckert and Mauchly's ENIAC and EDVAC, which was widely publicized.

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.

ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC's construction in August 1944, and design work for the EDVAC commenced before the ENIAC was fully operational.

Like the ENIAC, the EDVAC was built for the U. S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the University of Pennsylvania's Moore School of Electrical Engineering.

The final cost of EDVAC, however, was similar to the ENIAC's, at just under $ 500, 000.

The EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory capacity of 1, 000 44-bit words ( later set to 1, 024 words, thus giving a memory, in modern terms, of 5. 5 kilobytes ).

EDVAC was delivered to the Ballistics Research Laboratory in August 1949.

By 1960 EDVAC was running over 20 hours a day with error-free run time averaging eight hours.

EDVAC ran until 1961 when it was replaced by BRLESC.

John William Mauchly ( August 30, 1907 – January 8, 1980 ) was an American physicist who, along with J. Presper Eckert, designed ENIAC, the first general purpose electronic digital computer, as well as EDVAC, BINAC and UNIVAC I, the first commercial computer made in the United States.

He produced what was understood to be an internal document describing the EDVAC.

Dated June 30, 1945, it was an early written account of a general purpose stored-program computing machine ( the EDVAC ).

The ENIAC patent, issued in 1964 was filed on June 26, 1947, and granted February 4, 1964, but the public disclosure of design details of EDVAC in the First Draft ( which were also common to ENIAC ) was later cited as one cause for the 1973 invalidation of the ENIAC patent.

ILLIAC I was based on the Institute for Advanced Study ( IAS ) Von Neumann architecture as described by mathematician John von Neumann in his influential First Draft of a Report on the EDVAC.

At about the same time, EDVAC was under development at the University of Pennsylvania's Moore School of Electrical Engineering, and the University of Cambridge Mathematical Laboratory was working on EDSAC.

EDVAC, one of the first stored program computers

* EDVAC binary electronic stored program computer incorporating high speed delay line memory begins operation at the United States Army's Ballistics Research Laboratory at Aberdeen Proving Ground.

Many early electronic computers were based on the First Draft of a Report on the EDVAC report published in 1945.

During his tenure the Moore School built the ENIAC, the first general-purpose electronic digital computer, and began construction on its successor machine, the EDVAC.

Tube computers like EDVAC tended to average eight hours between failures, whereas relay computers like the ( slower, but earlier ) Harvard Mark I failed very rarely.

The architecture for the first two UIUC computers was taken from a technical report from a committee at the Institute for Advanced Study ( IAS ) at Princeton, First Draft of a Report on the EDVAC, edited by John von Neumann ( but with ideas from Eckert & Mauchley and many others.

* Preliminary design work on the ENIAC's successor machine the EDVAC resulted in the stored program concept used in all computers today, the logical design having been promulgated in John von Neumann's First Draft of a Report on the EDVAC, a set of notes synthesized from meetings he attended at the Moore School.

These instructions could be combined to create useful programs for the EDVAC to run.

Significantly, the programs written for EDVAC were stored in high-speed computer memory rather than specified by the physical wiring of the computer.

With von Neumann's design, the program, or software, that EDVAC ran could be changed simply by changing the contents of the memory.

While von Neumann is most often credited with the design of the stored-program computer because of his design of EDVAC, others before him, such as Konrad Zuse, had suggested and implemented similar ideas.

Eckert and Mauchly started work on a new design, to be later called the EDVAC, which would be both simpler and more powerful.

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.

Eckert, a co-inventor of ENIAC, discusses its development at the University of Pennsylvania's Moore School of Electrical Engineering ; describes difficulties in securing patent rights for ENIAC and the problems posed by the circulation of John von Neumann's 1945 First Draft of the Report on EDVAC, which placed the ENIAC inventions in the public domain.

Warren served as supervisor of the EDVAC project ; central to his discussion are J. Presper Eckert and John Mauchly and their disagreements with administrators over patent rights ; discusses John von Neumann's 1945 draft report on the EDVAC, and its lack of proper acknowledgment of all the EDVAC contributors.

Eckert, a co-inventor of the ENIAC, discusses its development at the University of Pennsylvania's Moore School of Electrical Engineering ; describes difficulties in securing patent rights for the ENIAC and the problems posed by the circulation of John von Neumann's 1945 First Draft of the Report on EDVAC, which placed the ENIAC inventions in the public domain.

The EDVAC as installed in Building 328 at the Ballistics Research Laboratory.

The contract named the device the Electronic Discrete Variable Automatic Calculator.

de: Electronic Discrete Variable Automatic Computer

fr: Electronic Discrete Variable Automatic Computer

* V. Gurevich " Electronic Devices on Discrete Components for Industrial and Power Engineering ", CRC Press, New York, 2008, 418 p.