UNIVAC 1103 - AbsoluteAstronomy.com

The UNIVAC 1103 or ERA 1103, a successor to the UNIVAC 1101

UNIVAC 1101

The UNIVAC 1101, or ERA 1101, was a computer system designed by Engineering Research Associates and built by the Remington Rand corporation in the 1950s. It was the first stored program computer in the U.S. that was moved from its site of manufacture and successfully installed at a distant site...

, was a computer system designed by Engineering Research Associates

Engineering Research Associates

Engineering Research Associates, commonly known as ERA, was a pioneering computer firm from the 1950s. They became famous for their numerical computers, but as the market expanded they became better known for their drum memory systems. They were eventually purchased by Remington Rand and merged...

and built by the Remington Rand

Remington Rand

Remington Rand was an early American business machines manufacturer, best known originally as a typewriter manufacturer and in a later incarnation as the manufacturer of the UNIVAC line of mainframe computers but with antecedents in Remington Arms in the early nineteenth century. For a time, the...

corporation in October, 1953. It was the first computer for which Seymour Cray

Seymour Cray

Seymour Roger Cray was an American electrical engineer and supercomputer architect who designed a series of computers that were the fastest in the world for decades, and founded Cray Research which would build many of these machines. Called "the father of supercomputing," Cray has been credited...

was credited with design work.

History

Even before the completion of the Atlas (UNIVAC 1101), the Navy asked Engineering Research Associates to design a more powerful machine. This project became Task 29, and the computer was designated Atlas II.

In 1952, Engineering Research Associates asked the Armed Forces Security Agency (the predecessor of the NSA) for approval to sell the Atlas II commercially. Permission was given, on the condition that several specialized instructions would be removed. The commercial version then became the UNIVAC 1103. Because of security classification

Classified information in the United States

The United States government classification system is currently established under Executive Order 13526, the latest in a long series of executive orders on the topic. Issued by President Barack Obama in 2009, Executive Order 13526 replaced earlier executive orders on the topic and modified the...

, Remington Rand

Remington Rand

management was unaware of this machine before this.

Remington Rand announced the UNIVAC 1103 in February 1953. The machine competed with the IBM 701

IBM 701

The IBM 701, known as the Defense Calculator while in development, was announced to the public on April 29, 1952, and was IBM’s first commercial scientific computer...

in the scientific computation market. In early 1954, a committee of the Joint Chiefs of Staff

Joint Chiefs of Staff

The Joint Chiefs of Staff is a body of senior uniformed leaders in the United States Department of Defense who advise the Secretary of Defense, the Homeland Security Council, the National Security Council and the President on military matters...

requested that the two machines be compared for the purpose of using them for a Joint Numerical Weather Prediction project. Based on the trials, the two machines had comparable computational speed, with a slight advantage for IBM's machine, but the later was favored unanimously for its significantly faster input-output equipment.

The successor machine was the UNIVAC 1103A or Univac Scientific, which improved upon the design by replacing the unreliable Williams tube

Williams tube

The Williams tube or the Williams-Kilburn tube , developed in about 1946 or 1947, was a cathode ray tube used to electronically store binary data....

memory with magnetic core memory

Magnetic core memory

Magnetic-core memory was the predominant form of random-access computer memory for 20 years . It uses tiny magnetic toroids , the cores, through which wires are threaded to write and read information. Each core represents one bit of information...

, adding hardware floating point

Floating point

In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...

instructions, and a hardware interrupt

Interrupt

In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....

feature.

Technical details

The system used electrostatic storage, consisting of 36 Williams tube

Williams tube

The Williams tube or the Williams-Kilburn tube , developed in about 1946 or 1947, was a cathode ray tube used to electronically store binary data....

s with a capacity of 1024 bit

Bit

A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

s each, giving a total random access memory of 1024 words of 36 bits each. Each of the 36 Williams tubes was five inches in diameter. A magnetic drum memory

Drum memory

Drum memory is a magnetic data storage device and was an early form of computer memory widely used in the 1950s and into the 1960s, invented by Gustav Tauschek in 1932 in Austria....

provided 16,384 words. Both the electrostatic and drum memories were directly addressable: addresses 0 through 01777 (Octal

Octal

The octal numeral system, or oct for short, is the base-8 number system, and uses the digits 0 to 7. Numerals can be made from binary numerals by grouping consecutive binary digits into groups of three...

) were in electrostatic memory and 040000 through 077777 (Octal

Octal

) were on the drum.

Fixed-point

Fixed-point arithmetic

In computing, a fixed-point number representation is a real data type for a number that has a fixed number of digits after the radix point...

numbers had a 1-bit sign and a 35-bit value, with negative values represented in ones' complement format.

Instructions

Instruction set

An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...

had a 6-bit operation code and two 15-bit operand addresses.

Programming systems for the machine included the RECO regional coding assembler by Remington-Rand, the RAWOOP one-pass assembler and SNAP floating point interpretive system authored by the Ramo-Wooldridge Corporation

TRW

TRW Inc. was an American corporation involved in a variety of businesses, mainly aerospace, automotive, and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers, software and systems engineering. TRW built many spacecraft,...

of Los Angeles

Los Ángeles

Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

, the FLIP floating point

Floating point

interpretive system by Consolidated Vultee Aircraft

Convair

Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Vultee Aircraft and Consolidated Aircraft, and went on to produce a number of pioneering aircraft, such as the Convair B-36 bomber, and the F-102...

of San Diego, and the CHIP floating point interpretive system by Wright Field

Wright-Patterson Air Force Base

Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...

in Ohio

Ohio

Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...

1103A

The UNIVAC 1103A or Univac Scientific was an upgraded version introduced in March, 1956.
Significant new features on the 1103A were its magnetic core memory, and the addition of interrupt

Interrupt

In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....

s to the processor. The UNIVAC 1103A had up to 12,288 words of 36 bit magnetic core memory, in one to three banks of 4,096 words each.

Fixed-point

Fixed-point arithmetic

In computing, a fixed-point number representation is a real data type for a number that has a fixed number of digits after the radix point...

numbers had a 1 bit sign and a 35 bit value, with negative values represented in ones' complement format. Floating-point

Floating point

numbers had a 1 bit sign, an 8 bit characteristic, and a 27 bit mantissa. Instructions

Instruction set

had a 6 bit operation code and two 15-bit operand addresses.

The 1103A was contemporary and competitor to the IBM 704

IBM 704

The IBM 704, the first mass-produced computer with floating point arithmetic hardware, was introduced by IBM in 1954. The 704 was significantly improved over the IBM 701 in terms of architecture as well as implementations which were not compatible with its predecessor.Changes from the 701 included...

, which also employed vacuum tube logic, magnetic core memory, and hardware floating point.

History

Technical details

1103A

Further reading