Early Popular Computers, 1950 - 1970 (2023)

This article was originally written as part ofIEEE STARSprogram.

Citation

The introduction in 1951 of the large-scale UNIVAC computer from Remington Rand began a three-decade transition from over half a century of data processing on punched card equipment to the widespread use of stored-program computers. While large companies profitably used early large-scale computers, most companies could not afford them. The transition to computers gained momentum in the mid-1950s with the introduction of the magnetic drum IBM 650 and the magnetic disk IBM 305, and again in the 1960s with the magnetic core and the transistorized IBM 1401. With shipments tripling each year, computer revenues exceeded revenues for punch card equipment in 1962.

Introduction

Over the past six decades, the raw processing power of computers has increased by six orders of magnitude, while the cost has decreased by three orders of magnitude. Computers have become ubiquitous, invisibly embedded in everyday things such as cell phones, cameras, cars, and entertainment systems.

By comparison, in the early 1950s, only the largest companies and institutions could afford a computer. Leasing for about $200,000 a month in inflation-adjusted 2010 dollars, the large-scale computer occupied about a hundred square feet, used thousands of vacuum tubes, consumed over a hundred kilowatts, and required full-time operations and maintenance staff.

To expand the market, vendors strove to offer computers to replace the punch card equipment widely used by businesses and institutions for over half a century. In this essay, we highlight the most popular and widely used computers from the early 1950s through the 1960s. These computers, manufactured in significant quantities for their time, spearheaded the transition from punch card equipment to stored program computing.

Equipment for punch cards

Beginning with the invention of the tabulator, keypunch, and sort in the late 1880s, punch card equipment gradually became more versatile and widely used in the automation of business tasks such as payroll, invoicing, inventory, and accounts receivable. By 1950, vendors such as IBM, Remington Rand, and Bull offered a variety of punch card machines: keypunches, accounting/tabulators (printers), sorters, collators, calculators, interpreters, and reproducers. IBM's rectangular-punched cards, introduced in 1928, had up to 80 characters, while Remington Rand's circular-punched cards, introduced two years later, had up to 90 characters.

Punched card equipment processed stacks of cards, most machines tailored to a specific task by a removable plugboard control panel. By manually connecting patch cables, users "programmed" calculation or control steps and card movement from input card bins to output card stackers. Punched card machines were electromechanical and used electrical circuits, relays and electromagnets for control and electric motors to move punched cards and paper via pulleys, rollers, gears, levers and blades.

Small business firms in the 1950s automated their data processing tasks by leasing a selection of punched card machines for about $2,500 per month ($20,000 adjusted for inflation). They consumed millions of punch cards a year, which often cost more than the rental of equipment itself.

First introduced in 1931, the electromechanical multiplication punch complemented accounting machines and was also used for scientific and engineering calculations. In 1946, IBM announced its 603 electronic multiplier, the first vacuum tube calculator; two years later it introduced the more capable 604 Electronic Calculating Punch. Renting for $550 per month ($5,000 adjusted for inflation), the 604 could multiply or divide about a dozen numbers per second. Not today's handheld calculator, it had 1,400 vacuum tubes, weighed 630 kg and consumed 8,000 watts.

In 1948, engineers at Northrop Aircraft in California got IBM to develop its Card-Programmed Calculator (CPC). While a stored-program computer executes instructions and data from main memory, the CPC used an amplified 604 to execute instructions from punch cards. About 4,500 IBM 604s and 700 CPCs were installed worldwide by the mid-1950s. Users affectionately referred to the CPC as "a poor man's ENIAC."

Early large-scale commercial computers

In 1951, the US Census Bureau began using Remington Rand's UNIVAC computer with stored programs. It rented for $16,000 a month ($130,000 adjusted for inflation), had a memory of 1000 words at 12 characters per word, and offered magnetic tape drives and a 600-line-per-minute printer. A total of 43 UNIVACs were ultimately delivered to businesses and institutions during the 1950s.

In 1953, IBM delivered its 701 Electronic Data Processing Machine, a large-scale computer for scientific and engineering applications, including national defense calculations. Two years later, IBM introduced its 702 computing system to businesses.

Other large-scale American manufacturers of commercial computers in the 1950s included Burroughs, Datamatic, Engineering Research Associates (ERA), GE, NCR, RCA, and Philco. European manufacturers included Bull, Elliott, Electrologica, EMI, English Electric, Facit, Ferranti, ICT, Lyons, Olivetti, SEA, Siemens and Zuse. By the late 1950s, a dozen American suppliers had supplied approximately 450 large-scale computers, 350 of which were from IBM.

Large companies found that, despite their high cost, large-scale computers could pay for themselves by consolidating accounting, clerical, and record-keeping services across various departments. Also by applying mathematical algorithms from the field of operations research, manufacturing companies could optimize their distribution of goods and materials. Companies and institutions proudly displayed computers in iconic glass-fronted rooms.

To bolster the prominence of large-scale computers, industry consultant Herbert Grosch argued that computing power was proportional to the square of a computer's cost: twice the price should yield four times the capacity. Nevertheless, despite "Grosch's Law", firms sought cheaper computers that they could fully control for faster programming development cycles and freedom from shared service interruptions.

Early mid-sized computers

In the mid-1950s, over a dozen intrepid suppliers attempted to provide inexpensive vacuum tube computers. Limited in their capabilities, none were shipped in quantities of more than a hundred or so.

While IBM was developing large computers at its laboratory in Poughkeepsie, New York, engineers at its upstate Endicott laboratory were designing a medium-sized computer based on a rotating magnetic drum for memory. Delivered in 1954, the IBM 650 Magnetic Drum Data Processing System targeted scientific, technical, and business applications [Figure 1]. Like the mainframes, it supported magnetic tape drives and also offered a scientific floating-point arithmetic option. A usable entry configuration leased for $4,000 per month ($32,000 adjusted for inflation). Using vacuum tubes for control circuitry, the 650 offered 2,000 words (of ten digits or five alphanumeric characters each) on a 10 cm diameter drum spinning at 12,500 revolutions per minute.

A few years later at IBM's new laboratory in San Jose, California, engineers pioneered a computer based on the world's first moving-head magnetic disk drive. The IBM 305 RAMAC (Random Access Method of Accounting and Control) was delivered in 1956 and targeted business applications such as inventory, invoicing, accounts receivable and transaction processing. The entry configuration leased for an attractive $3,200 per month ($25,000 adjusted for inflation). The 305 used vacuum tubes and a plugboard control panel and could execute up to 200 instructions from a small magnetic drum memory. The RAMAC stored up to 5,000,000 characters on a stack of fifty 61 cm diameter disks spinning at 1,200 revolutions per minute.

In 1956, a computer census reported that three-quarters of the world's 1,100 computer installations were IBM 650s, making it by far the most popular computer at the time. Its numbers later peaked at 1,800 installations. The IBM 305 RAMAC was almost as successful, with over 1,000 delivered before its withdrawal in 1961.

Although the IBM 650 and 305 cost less than a fifth of a large computer, many small businesses still found them too expensive, with a monthly rental that exceeded their typical range of punch card machines.

During this time, computer design was usually aimed at either scientific or business applications, but not both. In general, scientific and engineering applications have benefited from the fastest possible arithmetic calculations, whereas data processing applications do not benefit from processing speeds faster than the input/output data rates of peripheral devices. A design focused on business computing applications along with lower cost circuitry was required before the financial needs of the punch card small business market could be met. This suggested a cost target close to the $2,500 monthly rental for a small business's typical array of punch card equipment.

Magnetic core arrays for memory

Early computers used ingenious but challenging memory technologies. Acoustic delay lines in the UNIVAC and rotating magnetic drums in ERA and IBM computers produced slow and uneven access times compared to the speed of vacuum tube circuits. The random electrostatic cathode ray tube memories used in the IBM 701 and 702 were fast enough, but not sufficiently reliable.

In the early 1950s, MIT's Jay Forrester, working on the government-funded Whirlwind computer project, pioneered a new type of memory that used arrays of tiny doughnut-shaped magnetic cores threaded by control wires [Figure 2]. Magnetizing a core clockwise or counterclockwise represented a binary 0 or 1. By late 1952, Forrester had demonstrated a 16×16 core-memory array, and IBM independently prototyped an 80×12 core array , which could buffer data from a punch card.

In late 1952, IBM entered into a contract with MIT for a new large-scale computer for SAGE, a huge real-time surveillance and control system to defend American airspace against the threat posed by the Soviet Union's bombers. The first SAGE computer was delivered in 1955 and used a large memory stack consisting of thirty-six 64×64 magnetic core arrays.

Until this time, magnetic core arrays were predominantly hand-assembled by women deftly threading hypodermic needles through selected cores, requiring forty hours per array. Because the SAGE installations would need tens of thousands of cores, IBM built a core threading machine and a facility capable of manufacturing and testing half a million cores per day.

By the late 1950s, almost all computers used memory arrays with a magnetic core. With sub-ten microsecond access times, they were much faster than acoustic serial delay lines and rotary drums – but not cheaper. At a monthly rent of about two cents per bit rents 4,000 characters of memory for about $640 a month, which is comparable to an accounting machine. (If these prices were still valid today—adjusted for inflation at $1 per byte per month—the rent for a 4-gigabyte memory would be $4 billion per month!)

Transistors for logic circuits

In 1947, researchers at Bell Labs invented the transistor, based on the semiconductor germanium. Several years later they introduced a more reliable and easier to manufacture alloy junction transistor. Originally more expensive, less reliable and slower than vacuum tubes, transistors were nevertheless predicted to become a hundred times cheaper, more reliable and faster.

By the mid-1950s, universities and research institutions had made prototypes of experimental transistorized computers. In 1954, IBM demonstrated a fully transistorized adaptation of their 604 calculator, which instead of 1,400 vacuum tubes used 2,200 alloy junction transistors, magnetic core memory, and 95% less power in half the space. In late 1957, IBM CEO Thomas J. Watson, Jr. banned the use of vacuum tubes in machine development, which accelerated their conversion to transistors. By the end of the year, IBM announced its 608 Electronic Calculator, the first commercial transistorized calculator.

In 1956, anticipating mass-produced transistorized computers, IBM chartered a small team in Poughkeepsie to automate the assembly of transistors. By 1959, a fully automated production line was operational and capable of turning out hundreds of alloy junction transistors per hour [Figure 3]. However, to the dismay of its creators, IBM decided not to manufacture transistors and transferred its automated manufacturing facility to Texas Instruments to supply IBM and others.

During this time, IBM also developed its Standard Modular System (SMS) for packaging discrete solid-state transistors and circuit components, a more compact successor to its vacuum tube modules. SMS printed circuit boards implemented basic computer circuits such as logic gates and single-bit latches [Figure 4]. In 1959, IBM began mass-producing SMS boards and wire-wrapped backplanes for its large-scale 7090 and for the Stretch supercomputer.

Early solid-state computers

With magnetic core memory and transistors in widespread production, the 1960s saw a dramatic increase in the number of computers, with shipments tripling each year. Table 1 lists the 23 earliest commercial computers supplied with magnetic core memory and transistor circuitry up to the end of 1960.

Philco was one of the first to come out in 1958 with its massive, solid-state scientific S-2000 Transistorized Automatic Computer. Using its innovative high-speed surface barrier transistor, it rivaled IBM's later large-scale scientific 7090 Data Processing System. The Electrologica company in the Netherlands also delivered its medium-sized solid-state X1 scientific computer in the same year.

Although the IBM 1401 Data Processing System was not the earliest solid-state commercial computer, it quickly became the world's most widely used and held that distinction through most of the 1960s [Figure 5]. The story behind the 1401's success is explained in part because it targeted the small business punch card user market while taking advantage of IBM's mass production capabilities and worldwide customer support organization, as described next in a case study of its product development.

Case Study: Development of the IBM 1401

The history of the 1401 begins in the early 1950s in France, when Compagnie des Machines Bull out competed IBM with its punch card machine that integrated a calculator and an accounting machine. In response, IBM convened a marketing study followed by parallel development efforts at its Paris, Böblingen, and Poughkeepsie laboratories. In 1955, the Paris laboratory's design for a World-Wide Accounting Machine was selected for the processing unit, along with new printer and punch card peripherals from the Böblingen laboratory. By 1957, a prototype was up and running, but its entry-level configuration exceeded the cost target and it used a plugboard control panel.

In connection with its Endicott laboratory, IBM assigned a young machine inventor and advocate of stored-program computing, Francis O. Underwood, to another attempt to formulate an inexpensive computing computer. He determined that the Paris design was suitable for character-oriented business computing applications with its serial-by-character data paths and variable-length strings and decimal numbers. However, its plugboard control panel was unsatisfactory because its transistorized interface was too expensive. The machine's total cost of ownership would also be higher, as users typically stocked multiple panels that are pre-wired for different tasks. So Underwood removed its control panel and designed an easy-to-use instruction set format to control its data paths. He named the new computer SPACE, for Stored-Program Accounting and Calculating Equipment, and struck a galvanizing chord after Sputnik's sensational appearance in space in October 1957.

At the same time, IBM had begun engineering development at its Endicott laboratory under Jonas Dayger to address its uncompetitive printer speeds. By 1958, its engineering team had prototyped a new printer using a rotating chain of character types that moved horizontally along a printed line, rather than moving perpendicular to the line as in existing drum or rod printers. Its prints were more pleasing to the eye because random horizontal variations in character positions are less noticeable than vertical shifts.

SPACE's program manager, Charles Branscomb, wisely adopted Dayger's innovative chain printer. He also rejected well-intentioned requests for additional features. Fortunately, he consented to an optional magnetic tape interface to enable card-to-tape and tape-to-printer tools to offload slower input/output tasks on large computer installations. By mid-1959, product marketing convinced IBM's forecasting department that customer demand warranted product launch and convened training courses to prepare the sales force for a "new dawn of computing."

On October 5, 1959, IBM announced the 1401 via closed circuit television to a worldwide audience of 50,000 in 102 cities. It was a runaway success. More than 3,000 orders poured in, exceeding its lifetime sales forecast in the first month and challenging the 5,000 computers in place worldwide. A year later, Time-Life Corporation in Chicago received the first production system.

With the 1401's rapid market success, IBM followed up with 1401-compatible systems: the more capable 1410, the smaller 1440, the faster 1460, and the large-scale 7010. According to industry census reports, 1400 family computers accounted for nearly half of the estimated 26,000 computers worldwide in 1965 [Figure 6]. Two years later, installations peaked at 14,600 systems out of an estimated 50,000 computers worldwide.

The 1401's entry-level configuration initially leased for $2,500 per month, achieving the target lease cost for a small business's typical array of punch card equipment. Over several years, customer demand for higher memory capacities and peripherals—magnetic tape drives, magnetic disk drives, optical and magnetic bank check readers—raised the average monthly rent to $6,500 ($50,000 inflation-adjusted).

The 1401's memory configurations ranged from 1,400 to 16,000 characters, and its processing unit supported variable-length character strings and decimal numbers. Its serial-by-character processor clock ran at 87,000 cycles per second, compatible with its peripheral input/output character rates. The 1401 mainframe used 10,800 transistors and consumed 4,000 watts. A complete system, counting magnetic cores, included approximately half a million discrete components. Nevertheless, 1401s were robust and reliable, and they were supported around the clock by IBM customer engineers who are on call. Many 1401 systems operated seven days a week and rarely broke down.

The introduction of the IBM 1401 abruptly transformed thousands of plugboard "programmers" into stored-program computer programmers. IBM offered an Autocoder assembler and COBOL, FORTRAN and Report Program Generator (RPG) compilers. An IBM user group founded in 1955, SHARE distributed hundreds of business, science, engineering, and math applications for free. Although IBM did not provide an operating system for the 1401, it did for the 1410 and 7010.

1401's succes

Key factors behind the IBM 1401's success included:

• IBM's designers tailored the 1401 for existing punch card equipment users, including an easy-to-use instruction format.
• Its entry-level configuration offered rentals comparable to a small business's typical range of punch card machines.
• Its 1403 chain printer produced the industry's highest quality output.
• The 1401's processing speed was balanced with peripheral data transfer rates, and its serial character-oriented architecture easily supported new peripherals.
• IBM's circuit designers used established and robust components, which resulted in high field reliability even when powered from low-quality electrical grids.
• IBM mass-produced its own standardized and interchangeable printed circuit boards in large quantities for a wide line-up of transistorized computers.
• IBM owned, leased and maintained its products using a worldwide customer support and service organization.

Due to its ease of use, robustness and popularity, the 1401 acquired a kind of mystique and lore. Computer historian Paul Ceruzzi noted that "users had an irrational devotion" to the 1401s. There were even programs that could whimsically reproduce melodies on the chain printer or evoke ethereal-sounding music from an AM radio.

1401 competition and succession

In late 1963, just four months before IBM was to announce its System/360 family of computers, Honeywell introduced its H-200 computer with 'Liberator' software that could run 1401 programs faster than a 1401. The unexpected appearance of The H-200 caught IBM off guard, initiating last-minute changes to their System/360 Model 30 to efficiently run 1401 software, thereby defending against Honeywell's astute forays.

Development of the 1400 family stopped with the announcement of the IBM System/360 in April 1964. But it wasn't until late 1968 that the new system's cheaper Model 20 and 30 overtook the 1400 family as the world's most popular computers. IBM retired the 1401 in 1971, twelve years after its introduction.

Transition from punch card equipment to computers

At the time of the 1401 announcement in late 1959, firms around the world employed over 300,000 punched card machines. With the rapid introduction of transistorized and magnetic core stored-program computers during the 1960s, demand for punched card equipment began to plateau and decline for accounting machines and calculators in particular.

Magnetic tape played a key role in the decline of punch card equipment. Since a single tape reel could hold the equivalent of tens of thousands of punch cards, peripheral data storage consumed much less physical space. For example, Time-Life Corporation transferred magazine subscribers from 40 million punch cards to just hundreds of magnetic tapes. Software applications were available to sort and merge data using magnetic tape drives instead of using sorters and sorters. To a degree not anticipated by 1401 product planners, about half of the 1400 family customers ultimately chose magnetic tape-oriented systems.

Because most computers in the 1960s still used punched cards for entering software and data, keypunch machines endured through the 1970s. In addition, punch card systems continued to be offered. In 1963, Sperry Rand introduced its UNIVAC 1004, a plugboard-controlled computing machine with a monthly rental of $1,900. With 3,400 installations, it was the second most popular system to the 1401 before the System/360. Also important, in 1969 IBM announced its System/3, a low-end business computer which used a smaller 96-character punch card and rented for only $1,000 per unit. month. By 1974, IBM had leased over 25,000 System/3s compared to over 150,000 computers supplied by 50 suppliers worldwide.

In summary, the development of transistors and magnetic core memories, along with the introduction of magnetic tape and disk drives, made stored-program computers more affordable and thus more widely used for business computing. By 1962, computer revenues had overtaken revenues from punch card equipment. With the 1970s introduction of electronic input and output terminals, the floppy disk for data exchange, and barcode labels for manufactured goods, the century-long era of punch card computing ended and the new era of stored program computing was firmly established.

Recognitions

The author is grateful to Emerson W. Pugh for providing editorial and technical guidance during the development of this article and to Richard Weaver, Jack Palmer, Paul Ceruzzi, Michael Williams, Ronald Mak, Dag Spicer, Charles Branscomb, and Mitchell Marcus for their generous and helpful feedback. And he would like to thank Paul Lasewicz for access to and reproduction of period IBM photographs. Any errors and omissions are solely attributable to the author.

Time line

• 1947, Bell Labs invents the transistor
• 1948, IBM leverer vakuumrør 604 Electronic Calculating Punch
• 1949, IBM delivers the 604-based Card-Programmed Electronic Calculator (CPC)
• 1951, Remington Rand delivers the vacuum-tube UNIVAC computer
• 1952, Bell labs introduces the alloy junction transistor
• 1954, IBM delivers the vacuum tube 650 Magnetic Drum Data Processing System
• 1955, IBM delivers magnetic-core vacuum tube SAGE air defense computer
• 1956, IBM delivers vacuum tube 305 RAMAC, first computer with magnetic disks
• 1958, Philco leverer S-2000 Transistorized Automatic Computer
• 1959, IBM announces the transistorized 1401 Data Processing System
• 1960, IBM 650 shipments exceed 1,000
• 1962, Computer revenues overtake revenues from punch card equipment
• 1964, IBM 1401 shipments exceed 10,000
• 1973, IBM System/360 Model 20 and 30 shipments exceed 20,000
• 1974, IBM System/3 shipments exceed 25,000

Bibliography

References of historical importance

F.O. Underwood. 1959. Data processing system. U.S. Patent 3,077,580, filed September 8, 1959

1956 – 1974. Monthly computer census. Computers and automation

1966. Computer Characteristics Quarterly. Adams Associates, Inc

References for further reading

Charles J. Bashe, Lyle R. Johnson, John H. Palmer, Emerson W. Pugh. 1986. IBMs tidlige computere. Cambridge, MA: MIT Press

Richard Thomas DeLamarter. 1986. Big Blue. New York: Dodd, Mead & Company

R. Garner, F. Dill. 2010. The legendary IBM 1401 computing system. IEEE Solid-State Circuits Magazine, Vol. 2, No. 1, pp. 28-39

Donald E. Knuth. 1986. The IBM 650: An appreciation from the field. Annals of the History of Computing, Vol. 8, No. 1, pp. 50-55

Emerson W. Pugh. 1995. Building IBM: Shaping an Industry and Its Technology. Cambridge, MA: The MIT Press

Michael R. Williams. 1997. A History of Computing Technology, 2. udgave. Los Alamitos, CA: IEEE Computer Society Press

About the author

Robert Garner's Silicon Valley career spans 33 years in management and engineering at Xerox Systems Development Division (STAR ​​workstation) and Palo Alto Research Center (PARC), Sun Microsystems (SPARC architecture, microprocessors and Sun-4 workstation), Brocade Communications and IBM Research. In 2004, he volunteered at the Computer History Museum to lead the restoration of an IBM 1401; and in 2009 he organized the "50th Anniversary of the Legendary IBM 1401" event at the Computer History Museum.