Talk:UNIVAC I

Section sequence
My rationale for placing the History sec above the Tech description sec was that I think the majority of readers will be primarily interested in the UNIVAC's practical impact and installation history (which institutions and companies bought those machines, what did they use them for). Those of us who are equally/more interested in the tech stuff are probably going to read the History sec anyway, and then dive into the juicy details. :-) --Wernher 05:36, 30 March 2006 (UTC)

Misc UNIVAC 1 info
--John Nagle (talk) 04:05, 29 July 2008 (UTC)
 * The Tektronix oscilloscope wasn't part of the computer and wasn't permanently attached to it. It was a standalone maintenance tool.
 * The Unityper was entirely mechanical. It wrote magnetic tapes by pushing permanent magnets against the tape and then advancing the tape.
 * The CPU had full redundancy and checking.
 * Case Institute of Technology had their UNIVAC I running until 1965.
 * The UNISERVO tape drives had motors powered by McIntosh audio amplifiers.

A Univac I was installed at the Carborundum Company in Niagara Falls, NY. about 1956. In addition to the High Speed Sheppard printer which printed a 130 character line at 600 lines per minute the installation included an off line paper tape to magnetic tape converter. The paper tape was read at a rate of 400 cps by a Feranti photo sensor. The processor was later modified to allow three instructions to be included per each word. I can't give any citation for the above other than I served as installation manager in 1956. We worked closely with Dr. Grace Hoppers group who aided us with the systems programming. A set of program(s) written in B-0 (later to be known as COBOL) was put into use in 1957 or so. I have a fairly extensive write up on that installatin that could be of interest. We used Frieden Flexowriters to create orders at remote sales offices. The business systems concepts were generated by two achademics from Warton and were refered to as "The Total Systems Concept". 68.205.85.149 (talk) 22:36, 22 October 2008 (UTC) Ronald F. Denz

Machine used to predict 1952 election
The article lead says: The fifth machine (built for the U.S. Atomic Energy Commission) was used by CBS to predict the result of the 1952 presidential election. However, according to this wired.com article, "The Univac in Philadelphia was connected to a teletype machine at the CBS studios in New York City. As the first precincts reported on election night, technicians used Unityper machines to encode the data onto paper tape to feed into Univac.", and the article indicates that the fifth machine was delivered in 1953 to the	Atomic Energy Commission in Livermore, CA. Was Eckert–Mauchly testing the fifth machine in Philadelphia in Nov. 1952, prior to its 1953 delivery to California? Clarification in the article would be helpful. (I think the wired article has an error. Unityper machines encoded data onto magnetic tape, not paper tape) --Wbm1058 (talk) 23:53, 9 February 2012 (UTC)

Additional Information from Original Texts
While the description here states that if a non-digit was encountered during an arithmetic operation, the machine would pass it to the output unchanged. However according to the Univac Programming Manual, 1st Revision 1953, it states that during add/subtract, if a non-numeral is encountered as data, the machine will stop and light a neon on the SC to indicate the type of fault.

Other tidbits- while reading from tape can be performed both forward and reverse, writing can only take place during forward motion. And the programmer must know which direction he wishes to read from tape as the instructions are specific. The UNIVAC could write at 20 char/inch for uniprinter intended output. Or at 100 char/inch for use by the machine proper at a later time. (The programmer must specify via instruction). Output was buffered in 60 word blocks. This information from my ’53 Programming Manual.

The wiki page states recording density of 128 bits/inch but according to the 1954 Manual of Operations (Remington Rand EL-210 Copyright 1954), density is actually 128 DIGITS per inch. A digit is 4 bits ‘numeric’, 2 bits ‘zone’ and 1 bit ‘parity’.

A couple of other things I don’t see mentioned but find impressive, especially when compared against later machines: It could read in data from any one of 10 Uniservos, write data to 2 different Uniservos, and continue to perform computations all simultaneously.

With regards to error checking- the 4 primary arithmetic registers were all redundant and results were continually compared. Odd parity checks were also used to verify input and the memory tanks were scanned for parity as the serial words recirculated. If a fault was encountered, a neon specific to that "area" would light.

In regards to the remark about the Unityper being entirely mechanical, I’m curious how it handled clearing of erroneous bits from tape. I know the operator could “backspace” and write over a mis-typed character. Not sure how it was done. — Preceding unsigned comment added by 192.43.65.245 (talk) 15:38, 16 July 2012 (UTC)

Someone who has the time should work in the information from the Univac patents. Notably: (yet another followup). These patents are loaded with buzzwords like Uniservo and circuit diagrams full of vacuum tubes. The illustrations include some wonderful perspective views of computer rooms. Douglas W. Jones (talk) 21:44, 28 August 2012 (UTC).
 * US Patent 3133190 for a Universal Automatic Computer Utilizing Binary Coded Alphanumeric Characters, issued to Eckert, Weiner, Shaw, and Welsh, assigned to Sperry Rand, Filed 1952, Issued 1964.
 * US Patent 3784983 for an Information Handling System (followup to the above).
 * US Patent 2708554 for a Tape Drive and Recording Apparatus, issued to Welsh, Schrolner, Mock, Eckert, assigned to Remington Rand, Filed 1950, Issued 1955.
 * US Patent 2901734 for a Tape Drive and Recording Apparatus (followup to the above).
 * US Patent 3189290 for a Tape Drive and Recording Apparatus

Are you sure that the BINAC was really a commercial computer?
There is no citation in the first footnote for the assertion that the BINAC was actually a "commercial" computer.

As far as I can tell, the single BINAC sold never did much of anything for the customer, Northrop, so while its sale could be considered a commercial transaction, I question whether the product delivered was actually a functional computer at all. In contrast, clearly the Univac I was a functional computer line. — Preceding unsigned comment added by 71.203.105.117 (talk) 17:04, 16 January 2015 (UTC)

Why not description of the memory in modern terms?
The section on memory has a lot of technical gobbledygook, but it doesn't translate that into a statement such as, "It had 1 megabyte of memory." Therefore, it is impossible to compare the UNIVAC memory to the memory of modern computers. — Preceding unsigned comment added by 184.147.120.87 (talk) 22:43, 17 January 2016 (UTC)

The "technical gobbleygook" ... I know I'm just an IP address anon but ... I'm only commenting because your phrasing did cause rage in my hardware heart. Okay... the simple reason, why aren't UNIVAC specs expressed in "modern" units: UNIVAC predates the power of 2 convention that modern units of memory are based on. Note UNIVAC uses 11-bit chunks, unlike today's machines that took on a base of 8-bits to a byte, later 16, then 32, 64 etc. Also it's really incredibly hard to express how... mechanical types of memory work to someone expecting the nice discreet electronic logics of today. There is a HUGE reason that core memory was a Big Deal (tm), and an advancement from things like delay line (is that right? the mechanical coil) or mercury delay memory (both those, were brilliant but core brought memory to an electronic level) at a time before... any concept of a unit of memory compatible with today's "bits and bytes." 135.26.188.215 (talk) 08:18, 27 January 2016 (UTC)

In popular culture
The end credits of Electric Dreams close with ‘Dedicated to the memory of the UNIVAC I’ HuwG 180.150.37.105 (talk) 11:59, 5 March 2021 (UTC)

Uncited material in need of citations
I am moving the following uncited material here until it can be properly supported with inline citations of reliable, secondary sources, per WP:V, WP:NOR, WP:CS, WP:NOR, WP:IRS, WP:PSTS, et al. This diff shows where it was in the article. Nightscream (talk) 16:45, 3 September 2022 (UTC)

Market positioning
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. After it predicted Eisenhower would have a landslide victory over Adlai Stevenson, as opposed to the final Gallup Poll which had predicted that Eisenhower would win the popular vote by 51–49 in a close contest, the CBS crew was so certain that UNIVAC was wrong that they believed it was not working.

As the election continued, it became clear it was correct all along: UNIVAC had predicted Eisenhower would receive 32,915,949 votes and win the Electoral College 438–93, while the final result had Eisenhower receive 34,075,029 votes in a 442–89 Electoral College victory. UNIVAC had come within 3.5% of Eisenhower's popular vote tally, and four votes of his electoral vote total.

... while computerized predictions were a must-have part of election night broadcasts.

Installations
As a result, the first installation was with the second computer, delivered to the Pentagon in June 1952.

UNIVAC installations, 1951–1954
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.

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 9 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.

Major physical features
...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 (382 ft²) of floor space.

Main memory details
The main memory consisted of 1000 words of 12 characters each. 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, 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 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.



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 non-standard modification called "Overdrive" did exist, that allowed for three four-character instructions per word under some circumstances. (Ingerman's simulator for the UNIVAC, referenced below, also makes this modification available.)

Digits were represented internally using excess-3 ("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 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.)

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 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 7,200 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 sort/merge 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 on-line 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: UNIVAC did not provide an 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.
 * The UNIPRINTER read metal UNIVAC magnetic tape using a tape reader and typed the data at 10 characters per second using a modified Remington typewriter.
 * The UNIVAC Card to Tape converter read punched cards at 240 cards per minute and wrote their data on metal UNIVAC magnetic tape using a UNISERVO tape drive.
 * A tape-to-card converter, that read a magnetic tape and produced punched cards.

Reliability
Eckert and Mauchly were uncertain about the reliability of digital logic circuits and little was known about them 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 burned-in 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 in-rush 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.