The UNIVAC 1103 or ERA 1103, a successor to the

UNIVAC 1101 The ERA 1101, later renamed UNIVAC 1101, was a computer system designed and built by Engineering Research Associates (ERA) in the early 1950s and continued to be sold by the Remington Rand corporation after that company later purchased ERA. Its ( ...

, is a

computer system A computer is a machine that can be programmed to automatically carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic sets of operations known as ''programs'', wh ...

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

and built by the

Remington Rand Remington Rand, Inc. was an early American business machine manufacturer, originally a typewriter manufacturer and in a later incarnation the manufacturer of the UNIVAC line of mainframe computers. Formed in 1927 following a merger, Remington ...

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

Seymour Cray Seymour Roger Cray (September 28, 1925 – October 5, 1996)
– was an American

Navy A navy, naval force, military maritime fleet, war navy, or maritime force is the military branch, branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral z ...

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,

management was unaware of this machine before this. The first commercially sold UNIVAC 1103 was sold to the

aircraft An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...

manufacturer

Convair Convair, previously Consolidated Vultee Aircraft Corporation, was an American aircraft-manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee ...

, where Marvin Stein worked with it. Remington Rand announced the UNIVAC 1103 in February 1953. The machine competed with the

IBM 701 The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May 2 ...

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

Joint Chiefs of Staff The Joint Chiefs of Staff (JCS) is the body of the most senior uniformed leaders within the United States Department of Defense, which advises the president of the United States, the secretary of defense, the Homeland Security Council and ...

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 IBM 701 was favored unanimously for its significantly faster

input/output In computing, input/output (I/O, i/o, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, such as another computer system, peripherals, or a human operator. Inputs a ...

equipment. The successor machines are the UNIVAC 1103A or ''Univac Scientific'', which improved upon the design by replacing the unreliable

Williams tube The Williams tube, or the Williams–Kilburn tube named after inventors Frederic Calland Williams, Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first Random-access memory, random-access digital storage devi ...

memory with

magnetic-core memory In computing, magnetic-core memory is a form of random-access memory. It predominated for roughly 20 years between 1955 and 1975, and is often just called core memory, or, informally, core. Core memory uses toroids (rings) of a hard magneti ...

, adding hardware

floating-point In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a ''significand'' (a Sign (mathematics), signed sequence of a fixed number of digits in some Radix, base) multiplied by an integer power of that ba ...

instructions, and perhaps the earliest occurrence of a hardware

interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted ...

feature. That was succeeded by the UNIVAC 1105.

Technical details

System Logic was done with around 3,900

vacuum tube A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. It ...

s (mostly

triode A triode is an electronic amplifier, amplifying vacuum tube (or ''thermionic valve'' in British English) consisting of three electrodes inside an evacuated glass envelope: a heated Electrical filament, filament or cathode, a control grid, grid ...

s) and 9,000

diode A diode is a two-Terminal (electronics), terminal electronic component that conducts electric current primarily in One-way traffic, one direction (asymmetric electrical conductance, conductance). It has low (ideally zero) Electrical resistance ...

s, in total at least 12 distinct tube types were used in the design. The system used electrostatic storage, consisting of 36

s with a capacity of 1024

bit The bit is the most basic unit of information in computing and digital communication. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as ...

s each, giving a total

random-access memory Random-access memory (RAM; ) is a form of Computer memory, electronic computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A random-access memory device allows ...

of 1024

words A word is a basic element of language that carries meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguists on its ...

of 36 bits each. Each of the 36 Williams tubes was in diameter. A magnetic

drum memory Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria. Drums were widely used in the 1950s and into the 1960s as computer memory. Many early computers, called drum computers or drum machines, used drum ...

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

Octal Octal (base 8) is a numeral system with eight as the base. In the decimal system, each place is a power of ten. For example: : \mathbf_ = \mathbf \times 10^1 + \mathbf \times 10^0 In the octal system, each place is a power of eight. For ex ...

) were in electrostatic memory and 040000 through 077777 (

) were on the drum. Fixed-point numbers had a 1-bit sign and a 35-bit value, with negative values represented in

ones' complement The ones' complement of a binary number is the value obtained by inverting (flipping) all the bits in the Binary number, binary representation of the number. The name "ones' complement" refers to the fact that such an inverted value, if added t ...

format. Instructions had a 6-bit operation code and two 15-bit

operand In mathematics, an operand is the object of a mathematical operation, i.e., it is the object or quantity that is operated on. Unknown operands in equalities of expressions can be found by equation solving. Example The following arithmetic expres ...

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 of

Los Angeles Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...

, the FLIP floating point arithmetic interpretive system by Consolidated Vultee Aircraft of

San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...

, and the CHIP floating-point interpretive system by Wright Field in

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

. The UNIVAC 1103/A weighed about .

1103A

The UNIVAC 1103A or Univac Scientific is an upgraded version introduced in March 1956. Significant new features on the 1103A were its

and the addition of

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 numbers had a one-bit sign and a 35-bit value, with negative values represented in

format.

Floating-point In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a ''significand'' (a Sign (mathematics), signed sequence of a fixed number of digits in some Radix, base) multiplied by an integer power of that ba ...

numbers had a one-bit sign, an eight-bit characteristic, and a 27-bit mantissa. Instructions had a six-bit operation code and two 15-bit operand addresses. The 1103A was contemporary with, and a competitor to, the

IBM 704 The IBM 704 is the model name of a large digital computer, digital mainframe computer introduced by IBM in 1954. Designed by John Backus and Gene Amdahl, it was the first mass-produced computer with hardware for floating-point arithmetic. The I ...

, which also employed vacuum-tube logic, magnetic-core memory, and floating-point hardware. A version of this machine was sold to the Lewis Research Center, NACA (

National Advisory Committee for Aeronautics The National Advisory Committee for Aeronautics (NACA) was a United States federal agency that was founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its ...

) in Cleveland, Ohio. It had the first magnetic core of 1096 words of 36 bits. The magnetic drum storage had a capacity of 16,384 words, and the clock speed is 500KHz. Input/output is

teletype A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Init ...

style

punched tape file:PaperTapes-5and8Hole.jpg, Five- and eight-hole wide punched paper tape file:Harwell-dekatron-witch-10.jpg, Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program ...

. When NACA became NASA in 1958, a series of improvements was begun to improve functionality and reliability. Over the next ten years, the machine was significantly upgraded by replacing the magnetic core with a commercial solid-state 16,384 word magnetic core system. An 8 unit magnetic tape system, a floating point arithmetic unit, and an

indirect addressing Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions ...

unit were designed and built in-house. All solid-state commercial electronics modules were interfaced to the vacuum tube electronics in the original machine.

1104

The 1104 system is a 30-

version of the 1103 built for

Westinghouse Electric The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse and headquartered in Pittsburgh, Pennsylvania. It was originally named "Westinghouse Electric & Manufacturing Company" and was ...

in 1957, for use on the BOMARC Missile Program. However, by the time the BOMARC was deployed in the 1960s, a more modern computer (a version of the AN/USQ-20, designated the G-40) had replaced the UNIVAC 1104.

1105

The UNIVAC 1105 is a follow-on computer to the UNIVAC 1103A introduced by Sperry Rand in September 1958. The main changes from the 1103 included a buffered I/O system and an optional third memory cabinet extending core memory by an additional 4,096 words.

Technical details

1103A

1104

1105

See also

References

Further reading