univac i univac i operators console univac i at franklin life insurance company the univac i universal automatic computer i was the first commercial computer produced in the united states the first univac was accepted by the united states census bureau on march 31 1951 and was dedicated on june 14 that year history market positioning remington rand employees harold e sweeney left and j presper eckert center demonstrate the us census bureaus univac for cbs reporter walter cronkite right univac i operators console closeup the univac i was the first american computer designed at the outset for business and administrative use with fast execution of relatively simple arithmetic and data transport operations as opposed to the complex numerical calculations required of scientific computers as such the univac competed directly against punchcard machines though the univac originally could neither read nor punch cards that shortcoming hindered sales to companies concerned about the high cost of manually converting large quantities of existing data stored on cards 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 however the early market share of the univac i was lower than the remington rand company wished to promote sales the company joined with cbs to have univac i predict the result of the 1952 presidential election univac i predicted eisenhower would have a landslide victory over adlai stevenson whom the pollsters favored the cbs crew was so certain that univac was wrong that they pretended it was not working as the election continued and it became clear it was correct all along the announcer admitted their sleight of hand and the machine became famous the result was a greater public awareness of computing technology and from then on computerized predictions were a musthave part of election night broadcasts installations univac i at census bureau with two operators the first contracts were with government agencies such as the census bureau the us 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 eckertmauchly computer corporation to remington rand due to the cost overruns on the project remington rand convinced nielsen and prudential to cancel their contracts the first sale to the census bureau was marked with a formal ceremony on march 31 1951 at the eckertmauchly divisions factory at 3747 ridge avenue philadelphia the machine was not actually shipped until the following december because as the sole fully setup model it was needed for demonstration purposes and the company was apprehensive about the difficulties of dismantling transporting and reassembling the delicate machine as a result the first installation was with the second computer delivered to the pentagon in june 1952 univac installations 19511954 date customer comments 1951 us census bureau suitland md not shipped until 1952 1952 us air force pentagon arlington va 1952 us army map service washington dc operated at factory aprilseptember 1952 1953 new york university for the atomic energy commission new york ny 1953 atomic energy commission livermore ca 1953 us navy david w taylor model basin bethesda md 1954 remington rand sales office new york ny 1954 general electric appliance division louisville ky first business sale 1954 metropolitan life new york ny 1954 us air force wrightpatterson afb dayton oh 1954 us steel pittsburgh pa 1954 du pont wilmington de 1954 us steel gary in 1954 franklin life insurance springfield il 1954 westinghouse pittsburgh pa 1954 pacific mutual life insurance los angeles ca 1954 sylvania electric new york ny 1954 consolidated edison new york ny originally priced at us159000 the univac i rose in price until they were between 1250000 and 1500000 a total of 46 systems were eventually built and delivered 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 the univac i at case was still operable in 1965 but had been supplanted by a univac 1107 a few univac i systems stayed in service long after they were made obsolete by advancing technology the census bureau used its two systems until 1963 amounting to 12 and nine years of service respectively 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 13 years of service technical description mercury delay line memory of univac i major physical features univac i used about 5000 vacuum tubes consumed 125 kw and could perform about 1905 operations per second running on a 225 mhz clock the central complex alone ie the processor and memory unit was 43 m by 24 m by 26 m high the complete system occupied more than 355 m 382ft of floor space 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 10word mercury delay line registers the inputoutput buffers were 60 words each consisting of 12 channels of 10word mercury delay line registers there are six channels of 10word mercury delay line registers as spares with modified circuitry seven more channels control the temperature of the seven mercury tanks and one more channel is used for the 10 word y register the total of 126 mercury channels is contained in the seven 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 each 10word mercury delay line channel is made up of three sections a channel in a column of mercury with receiving and transmitting quartz piezoelectric crystals mounted at opposite ends an intermediate frequency chassis connected to the receiving crystal containing amplifiers detector and compensating delay mounted on the shell of the mercury tank a recirculation chassis containing cathode follower pulse former and retimer modulator which drives the transmitting crystal and input clear and memoryswitch gates mounted in the sections adjacent to the mercury tanks instructions and data instructions were six alphanumeric characters packed two instructions per word the addition time was 525 microseconds and the multiplication time was 2150 microseconds a nonstandard modification called overdrive did exist that allowed for three fourcharacter instructions per word under some circumstances ingermans simulator for the univac referenced below also makes this modification available internal view of univac i digits were represented internally using excess3 xs3 binary coded decimal bcd arithmetic with six 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 11digit 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 nondigit character was encountered in a position during an arithmetic operation the machine passed it unchanged to the output and any carry into the nondigit was lost note however that a peculiarity of univac is additionsubtraction 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 inputoutput besides the operators console the only io devices connected to the univac i were up to 10 uniservo tape drives a remington standard electric typewriter and a tektronix oscilloscope the uniservo was the first commercial computer tape drive commercially sold it used data density 128 bits per inch with real transfer rate 7200 characters per second on magnetically plated phosphor bronze tapes the uniservo could also read and write unityper created tapes at 20 bits 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 sortmerge data processing applications large volumes of data could be submitted as input via magnetic tapes created on offline card to tape system and made as output 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 online typewriter was typically used for announcing program breakpoints checkpoints and for memory dumps operations a typical univac i installation had several ancillary devices there were typically a printer that read a magnetic tape and printed output on continuousform paper a cardtotape converter that read punched cards and recorded their images on magnetic tape and a tapetocard converter that read a magnetic tape and produced punched cards there was no univac provided operating system operators loaded on a uniservo a program tape which could be loaded automatically by processor logic the appropriate source and output data tapes would be mounted and the program started results tapes then went to the offline printer or typically for data processing into short term storage to be updated with the next set of data produced on the offline card to tape unit the mercury delay line memory tank temperature was very closely controlled as the speed of sound in mercury varies with temperature in the event of a power failure many hours could elapse before the temperature stabilized reliability eckert and mauchly were uncertain about the reliability of digital logic circuits and little was known at the time the univac i was designed with parallel computation circuits and result comparison in practice only failing components yielded comparison faults as their circuit designs were very reliable tricks were used to manage the reliability of tubes prior to use in the machine large lots of the predominant tube type 25l6 were burned in and carefully tested often half of a production lot would be thrown away technicians installed a tested and burnedin tube in an easily diagnosed location such as the memory recirculate amplifiers then when aged further this golden tube was sent to stock to be used in a difficult to diagnose logic position it took about 30 minutes to turn on the computer as all filament power supplies were stepped up to operating value over that time to reduce inrush current and thermal stress on the tubes as a result uptimes mtbf of many days to weeks were obtained on the processor the uniservo did not have vacuum columns but springs and strings to buffer tape from the reels to the capstan these were a frequent source of failures wikimedia commons has media related to univac i list of univac products history of computing hardware list of vacuum tube computers ferranti mark 1 grace hopper notes univac conference oral history on 1718 may 1990 charles babbage institute university of minnesota minneapolis 171page transcript of oral history with computer pioneers including jean bartik involved with the univac computer held on 1718 may 1990 the meeting involved 25 engineers programmers marketing representatives and salesmen who were involved with the univac as well as representatives from users such as general electric arthur andersen and the us census margaret r fox papers 19351976 charles babbage institute university of minnesota collection contains reports including the original report on the eniac univac and many early inhouse national bureau of standards nbs activity reports memoranda on and histories of seac swac and dyseac programming instructions for the univac larc and midac patent evaluations and disclosures relevant to computers system descriptions speeches and articles written by margaret foxs colleagues and correspondence of samuel alexander margaret fox and samuel williams univac i documentation from computer documentation repository wwwbitsaversorg univac 1 the first massproduced computer unisys history newsletter volume 5 number 1 at the wayback machine archived april 22 2017 the univac and the legacy of the eniac from the university of pennsylvania library penn universityexhibitions univac 1 computer system by allan g reiter formerly of the era division of remington rand univac i ii simulator by peter zilahy ingerman shareware simulator of the univac i and ii archived download core memory slide show this slide show contains a photo of a 1951 core memory module for a univac i remingtonrand presents univac promotional film from the collection of the computer history museum mountain view california winky blinky lights off the broiler archiveis pictures and video in flash of univac main console sales and marketing documents 10 december 2012 archived from the original on 10 december 2012cs1 maint bot originalurl status unknown link want to buy a brain may 1949 popular science early illustrated article on the univac for the general public 