UNIVAC I Central Complex, containing the central processor and main memory unit.

The UNIVAC I (UNIVersal Automatic Computer I) was the first commercial made in the United States. It was designed principally by J. Presper Eckert and John Mauchly, the inventors of the ENIAC. Sign work was begun by their company, Eckert-Mauchly Computer Corporation, and was completed after the company had been acquired by Remington Rand. (In the years before successor models of the UNIVAC I appeared, the machine was simply known as "the UNIVAC".) Scanned from the Annuals of the History of Computing, Vol. ... Scanned from the Annuals of the History of Computing, Vol. ... “CPU” redirects here. ... Primary storage is a category of computer storage, often called main memory. ...

The first UNIVAC was delivered to the United States Census Bureau on March 31, 1951 and was dedicated on June 14th that year.[1] The fifth machine (built for the U.S. Atomic Energy Commission) was used by CBS to predict the result of the 1952 presidential election. With a sample of just 1% of the voting population it correctly predicted that Eisenhower would win. The UNIVAC I computers were built by Remington Rand's UNIVAC-division (successor of the Eckert-Mauchly Computer Corporation, bought by Rand in 1950). was delivered to the United States Census Bureau on March 31, 1951 and was dedicated on June 14th that year.^[1] The fifth machine (built for the U.S. Atomic Energy Commission) was used by CBS to predict the result of the 1952 presidential election. With a sample of just 1% of the voting population it correctly predicted that Eisenhower would win. The UNIVAC I computers were built by Remington Rand's UNIVAC-division (successor of the Eckert-Mauchly Computer Corporation, bought by Rand in 1950). The United States Census Bureau (officially Bureau of the Census as defined in Title ) is a part of the United States Department of Commerce. ... March 31 is the 90th day of the year in the Gregorian calendar (91st in leap years), with 275 days remaining. ... Year 1951 (MCMLI) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar. ... is the 165th day of the year (166th in leap years) in the Gregorian calendar. ... Shield of the U.S. Atomic Energy Commission. ... CBS Broadcasting, Inc. ... Presidential electoral votes by state. ... A Remington Rand branded typewriter Remington Rand was an early American computer manufacturer, best known as the original maker of the UNIVAC I, and now part of Unisys. ... UNIVAC serves as the catch-all name for the American manufacturers of the lines of mainframe computers by that name, which through mergers and acquisitions underwent numerous name changes. ... The Eckert-Mauchly Computer Corporation (EMCC) was founded by J. Presper Eckert and John William Mauchly, and was incorporated on December 22, 1947. ... Year 1950 (MCML) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar. ...

History

Market positioning

As well as being the first American commercial computer, the UNIVAC I was the first American computer designed at the outset for business and administrative use (i.e. for the fast execution of large numbers of relatively simple arithmetic and data transport operations, as opposed to the complex numerical calculations required by scientific computers). As such the UNIVAC competed directly against punch-card machines (mainly made by IBM), but oddly enough the UNIVAC originally had no means of either reading or punching cards (which initially hindered sales to some companies with large quantities of data on cards, due to potential manual conversion costs). This was corrected by adding offline card processing equipment, the UNIVAC Card to Tape converter and the UNIVAC Tape to Card converter, to transfer data between cards and UNIVAC magnetic tapes. A CTR census machine, utilizing a punched card system. ... For other uses, see IBM (disambiguation) and Big Blue. ... UNIVAC I Card to Tape converter - UNISERVO tape drive at left, converter in center, and card reader at right. ... This page is a candidate for speedy deletion. ...

Installations

A Remington Rand employee and J. Presper Eckert (center) demonstrate the U.S. Census Bureau's UNIVAC for CBS reporter Walter Cronkite (right).

The first contracts were with government institutions such as the Census Bureau, the Japan Air Force, and the US Army Map Service. Contracts were also signed by the ACNielsen Company, and the Prudential Insurance Company. Following the sale of Eckert-Mauchly Computer Corporation to Remington Rand, due to the cost overruns on the project, Remington Rand convinced Nielsen and Prudential to cancel their contracts. Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A Remington Rand branded typewriter Remington Rand was an early American computer manufacturer, best known as the original maker of the UNIVAC I, and now part of Unisys. ... Eckert and Mauchly examine a printout of ENIAC results in a newsreel from February 1946. ... Walter Leland Cronkite, Jr. ... The United States Census Bureau (officially Bureau of the Census as defined in Title ) is a part of the United States Department of Commerce. ... The Japan Air Self-Defense Force ), or JASDF, is the aviation branch of the Japan Self-Defense Forces responsible for the defense of Japanese airspace and other aerospace operations. ... ACNielsens Logo ACNielsen is an international marketing research firm, based in Schaumburg, Illinois. ... Prudential plc is a United Kingdom based financial services company. ...

The first sale, to the Census Bureau, was marked with a formal ceremony on March 31, 1951 at the Eckert–Mauchly Division's factory at 3747 Ridge Avenue, Philadelphia. The machine was not actually shipped until the following December, because, as the sole fully set-up model, it was needed for demonstration purposes, and the company was apprehensive about the difficulties of dismantling, transporting, and reassembling the delicate machine.^[2] So the first installation was with the second computer, delivered to the Pentagon in June 1952.

UNIVAC installations, 1951–1954^[3]

Originally priced at US$159,000, the UNIVAC I rose in price until they were between $1,250,000 and $1,500,000. A total of 46 systems were eventually built and delivered. ISO 4217 Code USD User(s) the United States, the British Indian Ocean Territory,[1] the British Virgin Islands, East Timor, Ecuador, El Salvador, the Marshall Islands, Micronesia, Palau, Panama, Turks and Caicos Islands, and the insular areas of the United States Inflation 2. ...

The UNIVAC I was too expensive for most universities, and Sperry Rand, unlike companies such as IBM, was not strong enough financially to afford to give many away. However Sperry Rand donated UNIVAC I systems to Harvard University (1956), the University of Pennsylvania (1957), and Case Institute of Technology in Cleveland, Ohio (1957). Harvard University (incorporated as The President and Fellows of Harvard College) is a private university in Cambridge, Massachusetts, USA and a member of the Ivy League. ... Year 1956 (MCMLVI) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... This article is about the private Ivy League university in Philadelphia. ... Year 1957 (MCMLVII) was a common year starting on Tuesday (link displays the 1957 Gregorian calendar). ... Case Western Reserve University is a private research university located in Cleveland, Ohio. ... Nickname: Motto: Progress & Prosperity Location in Cuyahoga County, Ohio, USA Coordinates: , Country State County Cuyahoga Founded 1796 Incorporated 1814 (village)   1836 (city) Government  - Mayor Frank G. Jackson (D) Area [1]  - City  82. ...

A few UNIVAC I systems stayed in service long after they were obsoleted by advancing technology. The Census Bureau used its two systems until 1963, amounting to twelve and nine years of service. Sperry Rand itself used two systems in Buffalo, New York until 1968. The insurance company Life and Casualty of Tennessee used its system until 1970, totaling over thirteen years of service. Nickname: Location of Buffalo in New York State County Government  - Mayor Byron Brown (D) Area  - City 52. ...

Technical description

Model of UNIVAC I system, c. 1954 (courtesy of the Smithsonian). Central Complex shown to the upper left.

Image File history File links Univac-model. ... Image File history File links Univac-model. ... The Smithsonian castle, as seen through the garden gate. ...

Major physical features

UNIVACUME I used 5,200 vacuum tubes,^[4] weighed 29,000 pounds (13 metric tons), consumed 125 kW, and could perform about 1,905 operations per second running on a 2.25 MHz clock. The Central Complex alone (i.e. the processor and memory unit) was 4.3 m by 2.4 m by 2.6 m high. The complete system occupied more than 35.5 m² of floor space. Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... Officially the pound is the name for at least three different units of mass: The pound (avoirdupois). ... A tonne (also called metric ton) is a non-SI unit of mass, accepted for use with SI, defined as: 1 tonne = 103 kg (= 106 g). ... The kilowatt (symbol: kW) is a unit for measuring power, equal to one thousand watts. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ...

Main memory details

The main memory consisted of 1000 words of 12 characters. When representing numbers, they were written as 11 decimal digits plus sign. The 1000 words of memory consisted of 100 channels of 10 word mercury delay line registers. The input/output buffers were 60 words each, consisting of 12 channels of 10 word mercury delay line registers. There are 6 channels of 10 word mercury delay line registers as spares. With modified circuitry, 7 more channels control the temperature of the 7 mercury tanks, and one more channel is used for the 10 word "Y" register. The total of 126 mercury channels is contained in the 7 mercury tanks mounted on the backs of sections MT, MV, MX, NT, NV, NX, and GV. Each mercury tank is divided into 18 mercury channels. In computing, word is a term for the natural unit of data used by a particular computer design. ... The decimal (base ten or occasionally denary) numeral system has ten as its base. ... In mathematics, negative numbers in any base are represented in the usual way, by prefixing them with a − sign. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery Standard atomic weight 200. ... Mercury memory of UNIVAC I (1951) Delay line memory was a form of computer memory used on some of the earliest digital computers, such as the EDSAC and UNIVAC I. // The basic concept of the delay line originated with World War II radar research, as a system to reduce clutter... Energy Input: The energy placed into a reaction. ...

Each 10 word mercury delay line channel is made up of three sections:

1. A channel in a column of mercury, with receiving and transmitting quartz piezo-electric crystals mounted at opposite ends.
2. An intermediate frequency chassis, connected to the receiving crystal, containing amplifiers, detector, and compensating delay, mounted on the shell of the mercury tank.
3. A recirculation chassis, containing cathode follower, pulse former and retimer, modulator, which drives the transmitting crystal, and input, clear, and memory-switch gates, mounted in the sections adjacent to the mercury tanks.

Quartz (from German Quarz[1]) is the second most common mineral in the Earths continental crust. ... For other uses, see Crystal (disambiguation). ...

Instructions and data

Instructions were 6 alphanumeric characters, packed 2 per word. The addition time was 525 microseconds and the multiplication time was 2150 microseconds. A non-standard modification called "Overdrive" did exist, that allowed for three 4-character instructions per word under some circumstances. (Ingerman's simulator for the UNIVAC, referenced below, also makes this modification available.) It has been suggested that some sections of this article be split into a new article entitled instruction set architecture. ... Generally speaking, the term alphanumeric refers to anything that consists of only letters and numbers. ... A microsecond is an SI unit of time equal to one millionth (10-6) of a second. ...

Digits were represented internally using excess-3 ("XS3") binary coded decimal (BCD) arithmetic with 6 bits per digit using the same value as the digits of the alphanumeric character set (and one parity bit per digit for error checking), allowing 11 digit signed magnitude numbers. But with the exception of one or two machine instructions, UNIVAC was considered by programmers to be a decimal machine, not a binary machine, and the binary representation of the characters was irrelevant. If a non-digit character was encountered in a position during an arithmetic operation the machine passed it unchanged to the output, and any carry into the non-digit was lost. (Note, however, that a peculiarity of UNIVAC I's addition/subtraction circuitry was that the "ignore", space, and minus characters were occasionally treated as numeric, with values of -3, -2, and -1 respectively, and the apostrophe, ampersand, and left parenthesis were occasionally treated as numeric, with values 10, 11, and 12.) Excess-3 binary coded decimal (XS-3) is a numeral system used in some old computers. ... Binary-coded decimal (BCD) is a numeral system used in computing and in electronics systems. ... A parity bit is a binary digit that indicates whether the number of bits with value of one in a given set of bits is even or odd. ... In telecommunication, a redundancy check is extra data added to a message for the purposes of error detection and error correction. ... In mathematics, negative numbers in any base are represented in the usual way, by prefixing them with a − sign. ...

Input/Output

Besides the operator's console, the only I/O devices connected to the UNIVAC I were up to 10 UNISERVO tape drives, a modified IBM electric typewriter^{[citation needed]} and a Tektronix oscilloscope. The UNISERVO was the first computer tape drive and normally operated at 128 characters per inch on magnetically plated phosphor bronze tapes. The UNISERVO could also read and write UNITYPER created tapes at 20 characters per inch. The UNITYPER was an offline typewriter to tape device, used by programmers and for minor data editing. Backward and forward tape read and write operations were possible on the UNIVAC and were fully overlapped with instruction execution, permitting high system throughput in typical sort/merge data processing applications. Large volumes of data could be inputted via magnetic tapes created on offline card to tape system and outputted via a separate offline tape to printer system. The operators console had three columns of decimal coded switches that allowed any of the 1000 memory locations to be displayed on the oscilloscope. Since the mercury delay line memory stored bits in a serial format, a programmer or operator could monitor any memory location continuously and with sufficient patience, decode its contents as displayed on the scope. The on-line typewriter was typically used for announcing program breakpoints, checkpoints, and for memory dumps. The American company Univac began as the business computer division of Remington Rand formed by the purchase of the Eckert-Mauchly Computer Corporation (EMCC) in 1950. ... Tektronix is a United States corporation that is currently a major presence in the test, measurement, and measuring industry. ... Illustration showing the interior of a cathode-ray tube for use in an oscilloscope. ...

See also

• List of UNIVAC products
• History of computing hardware

This is a list of UNIVAC products. ... Computing hardware has been an important component of the process of calculation and data storage since it became useful for numerical values to be processed and shared. ...

Notes

1. ^ Reference: CNN's feature on the 50th anniversary of the UNIVAC.
2. ^ Lecture session, UNISYS Corporation, May 17–18, 1990, Smithsonian Institution,
3. ^ Ceruzzi, Paul E. A history of modern computing, MIT, 1998. The source notes that the list is compiled from a number of sources and does not include UNIVACs that were completed not delivered in the period 1951-54. In some cases the dates are approximate. Depending on the definition of "installed" the order may be slightly different.
4. ^ The vacuum tubes used in the UNIVAC I were mostly of type 25L6, but the machine also used tubes of type 6AK5, 7AK7, 6AU6, 6BE6, 6SN7, 6X5, 28D7, 807, 829B, 2050, 5545, 5651, 5687, 6AL5, 6AN5, 6AH6, 5V4, 5R4, 4D32, 3C23, and 8008.

The 25L6 is an octal-based vacuum tube of the beam-power tetrode type. ...

External links

• UNIVAC I documentation – From computer documentation repository www.bitsavers.org
• Unisys History Newsletter, Volume 5, Number 1 – From Randy Carpenter's home page at Georgia Tech
• The UNIVAC and the Legacy of the ENIAC – From the University of Pennsylvania Library (PENN UNIVERSITY/exhibitions)
• UNIVAC 1 Computer System – By Allan G. Reiter, formerly of the ERA division of Remington Rand
• UNIVAC Simulator 1.2 – By Peter Zilahy Ingerman; Shareware simulator of the UNIVAC I and II