Robert Garner and Frederick (Rick) Dill

The development of the most popular of the 1960s and the story of its restoration at age 50.

he IBM 1401 Data lying technologies, we begin with its passing decks of cards with holes Processing System vacuum tube forebears. We cover punched in them through various was the world’s IBM’s development of the 1401’s electromechanical “unit record” ma- T most popular com- basic enabling technologies and chines. These machines sorted and puter during much trace its origins in business account- merged cards, did simple calculations, of the 1960s. Announced in 1959, it ing machines. We highlight its key punched cards, and printed reports. was one of IBM’s earliest transistor- features and characteristics, its mar- Most machines were controlled by ized . The IBM 1401 tran- ket succession, and even its appear- hand-wired plug boards tailored for sitioned thousands of businesses ance in popular culture. We also particular jobs. By the 1950s, IBM’s and institutions to stored-program describe the volunteer project at the operations from the leasing of unit computing, and its tape- and disk- Computer History Museum in Moun- record machines and the sale of bil- oriented systems freed users from tain View, California, that success- lions of punched cards each year the decades-long practice of storing fully restored two tape-oriented were very profitable. data on punched cards. In 1965, half 1401 systems to full operation. By this time, calculators with of all computers were IBM 1401s punched cards for input and output or members of its family. Figure 1 Early Accounting Machines, were being used to augment account- shows a tape-oriented 1401 system Calculators, and ing machines. Announced in 1948, from the 1960s. Stored-Program Computers the IBM 604 Electronic Calculating In this overview of the develop- For the first six decades of the 20th Punch was about the size of two ment of the IBM 1401 and its under- century, many businesses processed refrigerators. It was a vacuum tube, data for inventory, billing, receiv- -controlled, serial-decimal- Digital Object Identifier 10.1109/MSSC.2009.935295 ables, and payroll by repetitively digit machine with 50 digits of

28 WINTER 2010 IEEE SOLID-STATE CIRCUITS MAGAZINE 1943-0582/10/$26.00©2010IEEE

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. FIGURE 1: A tape-oriented IBM 1401 Data Processing System from the early 1960s. From left to right: 1402 Card Read Punch, 729 Magnetic Tape Unit, 1407 Console Inquiry Station, 1401 Processing Unit, 1403 . (Image courtesy of IBM Archives.)

storage that could multiply and rency) [2]. It was a stored-program (about US$180,000 to US$300,000 divide. In 1949, IBM also offered the computer with instructions and data today), versus only US$2,000 to Card-Programmed Calculator (CPC), residing in 2,000 words on a mag- US$2,500 per month for a set of unit a product that interconnected an IBM netic drum rotating at 12,500 r/min. record machines, such as a 604 Cal- 604 wired for common subroutines, By 1956, a dozen commercial firms culating Punch (US$650 per month), an extra storage unit, and the popu- had delivered about 1,000 stored- a 407 Accounting Machine (US$1,000 lar IBM 402 Accounting Machine [1]. program computers and 3,200 calcu- per month), a sorter, a collator, and About 4,500 IBM 604s and 130 CPCs lators, with IBM and the Univac so on [2], [3]. were installed [2]. division of Sperry Rand leading the Particularly during the 1950s, com - In 1951, UNIVAC pioneered the marketplace [2]. puter design was closely interwoven business stored-program computer. Broadly speaking, stored-program with rapidly evolving circuit tech- Soon thereafter, IBM and other com- computers were considerably more nologies and techniques. The 1950s puter manufacturers introduced com- flexible and adaptable than plug- vacuum tube computers—about puters for the business and scientific board-based accounting ma chines. 3,600 were installed commercially marketplaces. The IBM 650 Magnetic Their was easier to load, [2]—were typically based on diode Drum Data Processing Machine an- maintain, and distribute than wiring logic circuits with vacuum tube res- nounced in 1953 was the first widely and handling . However, toration of logic levels. Stored-pro- popular, low-cost business and scien- large-scale stored-program com- gram memories employed mercury tific computer. The 650 was installed puters were too expensive for all but electroacoustic delay lines (UNIVAC at more than a thousand customer the largest corporations. Typical I), electrostatic Williams cathode- sites and rented for about US$4,000 monthly rentals ranged from ray tubes (IBM 701 and 702), or other per month (US$32,000 in today’s cur- US$25,000 to US$40,000 per month approaches. Vacuum tubes suffered

IEEE SOLID-STATE CIRCUITS MAGAZINE WINTER 2010 29

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. from high heat dissipation and fila- transistors were far superior to point- quently grew into a working proto- ment burnout from thermal cycling, contact devices for digital logic cir- type of a fully transistorized 604, parameter drift, secondary emission, cuits because of their higher current publicly revealed in October 1954 and dust-induced cathode-to-grid gain, greater fan-out, and orders-of- and demonstrated in several U.S. shorts. Storage CRTs suffered from magnitude lower collector cutoff cur- cities [1], [6]. Based on this effort, internal particle contamination and rent. Even though alloy-junction was IBM’s 608 Transistor Calculator prod- proved difficult to manufacture. Vacuum slower and more temperature-sensi- uct was announced in April 1955, tube machines of this era were typically tive than point-contact, he advocated and it became the world’s first fully serviced several times per week. IBM for alloy-junction’s higher reliability transistorized commercial calcula- went so far as to establish a small in- and predictability, lower manufac- tor when delivered in December 1957 house pilot line to demonstrate reli- turing cost, and greater circuit ver- [1]. Nevertheless, only 32 units were able production of vacuum tubes satility [6]. produced, as it became outmoded by for computing machines [1]. For In 1953, Logue conducted a class other IBM products [4], [11]. Figure 2 main memory, concerted efforts by in transistor digital circuit design. shows a photo of a transistorized 604 printed-circuit card. In place of the IBM 604’s 1,400 Businesses and institutions throughout twin-triode tubes, the transistorized the world used the IBM 1401 in the 1960s version used 2,200 alloy-junction germanium transistors; it occupied to process rapidly growing amounts of half the volume and consumed 95% information. less power than the original. Even its power supplies and neon tube in- dicator drivers were solid-state, the IBM, MIT, and others made magnetic For lab assignments, six IBM vacuum first time all functions of a large core the technology of choice due to tube machines were reconfigured to electronic calculating machine were its high reliability and fast access use transistors. One of the projects implemented with transistors [1]. times. By 1956, IBM had automated was a cross section of the IBM 604 Its direct-coupled transistor and di- the production of its core memory calculator. The design project subse- ode-transistor logic ran at a 50-kHz planes [4]. cycle rate with 5-V signal swings [7]. To access its magnetic core memory, Early IBM Transistor Development three parallel transistors were and Manufacturing needed to drive a core half-select invented the transistor in line [4]. 1947 and broadly disclosed the tech- Although the transistorized 604 nology in the summer of 1951. It was very reliable, one issue with early continued to focus on the point-con- alloy-junction transistors was that tact germanium transistor, as did base resistance was too high for digital IBM’s initial transistor investiga- circuits. Logue attempted to convince tions. Although no one knew how to transistor vendors—GE, Raytheon, manufacture point-contact transis- RCA, and Westinghouse—to lower tors reliably with repeatable stable base resistance, but the effort was to characteristics and reasonable gain, no avail since their transistors met the their faster speed over junction needs of the more popular communi- transistors was attractive to com- cation applications. puter designers [1]. Also, due to a In 1954, a Poughkeepsie research negative resistance region at higher team (working in the site’s defunct emitter currents, a bistable latch pickle factory) began to design tran- could be implemented with just a sistors for use in future calculators single point-contact transistor in- and computers. To lower the transis- stead of a cross-coupled pair of tor’s base resistance, they used a transistors [5]. FIGURE 2: A printed-circuit logic card disk-shaped base with a ring contact In 1952, Joseph Logue joined IBM’s with germanium diodes and alloy-junc- around its circular periphery. The nascent transistor research group in tion transistors from the 1955 experimen- emitter was alloyed on one side of tal transistorized 604 calculator—basis of Poughkeepsie, New York, after trou- the IBM 608, world’s first fully transistor- the disk and a larger collector on the bleshooting IBM 701 storage tubes. ized commercial calculator. (Photograph other, allowing for some misalign- He concluded that alloy-junction courtesy of Robert Garner.) ment (see Figure 3).

30 WINTER 2010 IEEE SOLID-STATE CIRCUITS MAGAZINE

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. In 1956, anticipating the need to lower the manufacturing costs of its upcoming transistorized computers, IBM established a small group in Poughkeepsie responsible for mass- producing discrete transistors. By mid-1959, with Elliott Fritz as its lead mechanical engineer, IBM had constructed the world’s first fully automated production line for as - sembling alloy-junction transistors. The line comprised six assembly units, two ovens, and a welder and took about three hours to fully as - semble a transistor [1]. The automated room-sized facil- ity was a mechanical tour de force [8]. The assembly process started (a) (b) with sonic-driven Syntron bowls that FIGURE 3: A germanium alloy-junction n-p-n transistor (IBM 083) showing (a) its internal vibrated out only properly dimen- structure and (b) its hermetically sealed TO-5 package, as manufactured by IBM’s fully sioned preformed components: rect- automated transistor production line transferred to TI in 1959. (Photo courtesy of angular metallic base frames with a Robert Garner.) hole for the single-crystal germa- nium disk, emitter and collector manufacture electronic components. IBM’s new large-scale 7000-series alloy spheres, and two contact whis- Since Texas Instruments (TI) was transistorized mainframes used the kers and a mounting base. These already supplying 90% of IBM’s tran- Rolygon packaging. were inserted into a machined carbon sistors, IBM shipped their entire auto- The SMS Cube packaging com- fixture that held them in place in mated production line to TI in Oct ober prised 29-inch by 29-inch by 31-inch boats that moved between stations 1959 in exchange for three years’ frame modules, with four large card by means of a conveyer belt moni- exclusive use [1]. TI later replicated “gates” in the front and four gates in tored by photoelectric sensors. First, the facility several times and became the back. Cooling airflow was verti- the emitter sphere was alloyed into a major international supplier of cal, from bottom to top, with a fan in the germanium disk in a hydrogen germanium discrete transistors. each gate. Frame modules could be furnace; then the collector sphere stacked two high and two wide, for a was alloyed into the opposite side in a IBM’s Standard Modular System total capacity of 32 gates—the con- different furnace. In the zone-con- (SMS) of Circuits and Packaging figuration used by the 1401’s “main trolled furnaces, the germanium disk While perfecting the automated frame” processing unit (see Figure 4). melted in a controlled fashion along transistor production line, IBM was Gates easily swung outward 908 from its slow-dissolving <111>-oriented also planning for the automatic man- the frame or slid out for convenient surface, recrystallizing a thin layer ufacture of printed circuit boards maintenance. A logic gate could doped with the elements of the alloy (PCBs). Edward Garvey, after oversee- hold up to 144 single-width SMS dot. On further cooling, the alloy ing the design of 2,000 types of cards plugged into its single wire- solidified into a bump that held the vacuum tube modules for the IBM wrapped backplane. whisker wire contact. The boats were 700-series computers, realized the Figure 5 shows two sample SMS automatically disassembled, and then need for an automated facility for cards from the 1401: a typical single- the whiskers were welded to the assembling PCBs with solid-state width card and the less common package leads. The transistor was ex - components [1]. By 1958, with double-width card. Single-width SMS tracted, acid-etched, washed, dried, Logue’s transistorized 604 cards as a cards were 2.6 in wide by 4.5 in long, hermetically vacuum-sealed in a can starting point, the standardized engi- with components mounted on one with a powder to stabilize the mois- neering group in Endicott, New York, side. The cards had up to 16 contact ture content, and then tested. settled on the Standard Modular pads. When a card was inserted into IBM’s automated line was theoreti- System (SMS) for electronics packag- a backplane slot, the contact pad cally capable of producing 3,600 tran- ing. SMS defined two system packag- pressed against a thick gold dot on a sistors per hour, or 30 million ing options, called Cube and Rolygon. phosphor-bronze spring. The cards transistors a year—far more than IBM The IBM 1401 was the first system employed a gold-nickel-copper met- needed. IBM had earlier decided not to to use the Cube packaging, and allurgic stackup with a thick gold

IEEE SOLID-STATE CIRCUITS MAGAZINE WINTER 2010 31

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. schematics that others then redrew onto standard forms and key- punched into cards. The ALD software performed basic rule checking (outputs only to inputs, proper logic levels, net loading, and so on) and printed a machine’s full set of logic schematics on 17 inch by 22 inch C-sized paper with standardized symbols for logic gates and signal levels, page num- bers for inputs and outputs, SMS card block frame locations, and EC in formation. Designers had to man- ually verify path delays and timing since the software did not perform timing analysis. For computing circuits, IBM devel- oped several transistor logic families in the latter part of the 1950s, in- FIGURE 4: Restoration volunteer Ronald Williams and the 1401 processor “main frame” cluding nonsaturating current mode unit, which includes four SMS Cube frames with 24 gates of SMS cards (out of 32 total gate switching and saturating complemen- positions); the front panel with indicator lights, buttons, switches, and data paths; 4,000 tary transistor diode logic (CTDL). positions of magnetic core memory; and hard-wired cable bundles to peripherals. The 1401 processor contains about 2,300 SMS cards with 10,600 alloy-junction transistors and 13,200 Hannon Yourke at IBM invented cur- point-contact diodes. (Photo courtesy of Robert Garner.) rent mode logic with a typical gate delay of only 60 ns [1], which was overcoat on top (100 µin, or 2.54 µm) were wrapped to a post, which made deployed in the scientific IBM 7090 that precluded small surface pores it easier for a field engineering change and Stretch 7030 mainframes with and prevented corrosion of the under- (EC) to alter backplane wiring. In IBM’s 460-KHz clock cycle rates. With a lying layers. The thick gold layer product ion line, read- slower typical gate delay of 250 ns, eliminated the need for a special lubri- ers controlled automated Gardner- saturating CTDL was first deployed in cant or corrosion inhibitor chemical Denver wire-wrapping machines. the large-scale 250-kHz commercial on the contact surfaces. Also during this time, IBM pio- IBM 7070. An earlier study had found To ensure the reliable intercon- neered an early computer-aided that CTDL consumed 40% fewer tran- nection of wires between backplane design (CAD) system called auto- sistors than current mode switching pins, wire-wrap technology was used, mated logic diagram (ALD), which logic. Based on the IBM 7070 design with stiff solid-core wires snuggly initially ran on IBM 704 and 705 experience, CTDL was selected for wrapped around rectangular back- mainframes. Logic designers began the 1401’s logic circuits. plane posts. No more than two wires the CAD process by hand-sketching CTDL implemented and-or-in- verter (AOI) compound logic gates where parallel input diodes imple- mented the AND function followed by an open-collector wired-OR inverting transistor output (see Figure 6). The n-p-n gates had active high inputs and active low outputs; the reverse was true of the p-n-p gates. The n-p-n gate outputs could only be connected to p-n-p gate inputs. Other standard logic elements in- cluded emitter followers for driving large loads, latches, oscillators, and single-shot triggers. CTDL was robust and forgiving, FIGURE 5: Single- and double-width SMS cards from the IBM 1401 Processing Unit. (Photo and it handled large fan-ins and fan- courtesy of Robert Garner.) outs with wires of up to about 12 ft.

32 WINTER 2010 IEEE SOLID-STATE CIRCUITS MAGAZINE

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. +6M +6 B T1 P 34 N 15K P 430 Ω –0.2 H –6 C 56 Uh +6 220 Ω –12 B 0 +6 –6 220 Ω H 0 56 Uh C –0 N T1 83 –5.8 –6 P –12 N 15K 430 Ω

–6 –12M –12 (a) (b)

FIGURE 6: (a) A CTDL n-p-n active-high-input, active-low-output and-nor logic gate. (b) An n-p-n active-low-input, active-high-output and-or logic gate. The “H” output could be wired-OR’d to other gates without a load resistor. (Images courtesy of IBM.)

CTDL signal swings were 12 volts wanted engineering to move more credit interest-rate charges. Chris- peak-to-peak: n-p-n gates received quickly from tubes to transistors, tian de Waldner, the chairman of U levels centered about 26 V and however. So in October 1957, IBM’s IBM France, initiated an in-depth generated T levels centered about director of engineering issued a planning and study effort on the 0 V; the situation was reversed for decree that from that time on no part of IBM World Trade and domes- p-n-p gates. The 6-V offset allowed products would employ vacuum tic organizations that resulted in for 4.6 V of noise and load margin at tubes [1]. The dictate became known specifications for a combined tran- each logic level. Of course, it was within IBM as “Solid-state in ’58.” sistorized calculator and accounting not always possible that an output In meeting this challenge, by machine for the global market. signal would have the necessary 1958 IBM had invented all the Three IBM development laboratories level and logic polarity for a par- ticular input, so 15–20% of the gates existed only to convert between U Since the early 1950s, IBM’s CEO Thomas and T levels or between true and false polarities. , Jr. had led the company in a transition In 1958, IBM was already design- from electromechanical to electronic products. ing several large-scale computers using SMS technology: the scientific IBM 7090 (delivered in November design and manufacturing technol- in Paris (France), Böblingen (Ger- 1959), the commercial IBM 7070 ogies for delivering a high-volume many), and Poughkeepsie (New York) (delivered in March 1960), and the transistorized computer: magnetic held a competition in 1954 for the massive IBM 7030 Stretch supercom- core plane manufacturing, a fully best design. The Paris lab’s variable- puter (delivered in May 1961) [2]. automated transistor assembly word-length accounting machine Stretch contained more than 18,000 line, and automated PCB assembly. (VWLAM) design was selected for single-width SMS cards and 4,000 However, a plan for a mass-market the processing unit in the summer double-width cards [9]. However, computer in IBM’s product lineup of 1955. For peripherals, the IBM due to their high rental costs—an was proving to be elusive [10]. Böblingen lab designed a high-speed average of US$40,000 per month (or stick-based printer and punched US$300,000 today)—only about 800 Origins of the IBM 1401 . large-scale 7000-series computers In 1954, the French firm Machines The Paris processor design team, were delivered to customers [2]. Bull introduced a combined calcula- led by Maurice Papo and Eugene Since the early 1950s, IBM’s CEO tor and accounting machine called Estrems, at first wanted to design a Thomas Watson, Jr. had led the com- the Bull Gamma III that outsold IBM variable-data-length stored-program pany in a transition from electrome- products, particularly at French computer like the IBM 705. However, chanical to electronic products. He banks that frequently recalculated the initial estimate by a U.S.-based

IEEE SOLID-STATE CIRCUITS MAGAZINE WINTER 2010 33

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. costing department showed that the SPACE, for stored-program account- general, Branscomb resisted pres- design could not achieve its price tar- ing and calculating equipment— sure to add additional features, but gets, and the Paris team inauspi- striking a responsive chord as in early 1959 he agreed to incorpo- ciously reverted to plugboard-based Sputnik had just launched in rate an interface for controlling up control. Although the control panel October 1957. to six magnetic tape units. Thus, layout was clever, it soon became an Unlike existent stored-program by including magnetic tape sup- Achilles’ heel. computers with accumulators that port and keeping cost low, SPACE Renamed the World-Wide Account- had to be explicitly loaded from and became the preferred design for ing Machine (WWAM), the prototype stored into memory by software, offloading tape-to-print and card- was operational in the Paris lab by Underwood instead defined a memory- to-tape operations from high-end 1957. Even though the WWAM used a to-memory architecture without using mainframes [1]. By mid-1959, with the 40-person engineering team working night and In response to a 2004 ad in an IBM retirement day under engineering manager Jim newsletter, about 20 retired IBM employees Ingram, trial educational classes within IBM being spearheaded by mar- stepped up to the challenge of restoring a keting planner Sheldon Jacobs, and a 45-year-old 1401 acquired from Germany in prototype that achieved the entry- mostly unknown condition. level price target up and running, the renamed IBM 1401 was poised to trans- form the business world with its low plugboard for control, its projected an , thereby re ducing price, outstanding print quality, pow- price still came in significantly the number of instructions needed erful magnetic tape subsystem, and higher than the US$2,500 monthly for accounting and business pro- the promise of a stored-program com- rental target for an entry-level grams. He anticipated that the 1401’s puter for the mass marketplace. But system (US$18,000 in today’s cur- newly minted programmers would first Jacobs had to persuade IBM’s rency). In addition, the high-speed hand-code programs and manually skeptical forecasting department to German stick printer was deemed assign instructions to memory loca- sign off on the product launch. After too costly to maintain [1]. tions, so he selected easy-to-recall debating exactly which features small In 1957, Francis O. Underwood of instruction encodings and formats, business users really needed, IBM’s IBM Endicott’s Advanced Systems such as A for add and E for edit. He doubtful forecasters reluctantly Development Department (ASDD) also manually programmed several approved the 1401 as a revenue-neu- was asked to join a newly formed important algorithms, including the tral program just a few months before Accounting Machines Department French banking algorithm, to validate its announcement. under Ralph Mork and establish its that they fit in fewer than 1,400 On 5 October 1959, the 1401 was technical direction. He surveyed memory locations for the entry-level presented via closed-circuit televi- IBM’s attempts to design an inex- 1401 system. sion to 50,000 participants in 102 pensive transistorized accounting To achieve the ambitious entry- cities. In the following September, machine and decided that the WWAM level rental price target of US$2,500 the first 1401 was delivered to Time- had come closest with its familiar per month, Charles Branscomb, the Life in Chicago and by year end 100 and flexible serial-by- pro- Accounting Machine Department’s systems had been manufactured in cessing, decimal arithmetic, vari- new engineering program manager, Endicott and delivered to customers able-length numbers and strings, worked tenaciously with IBM’s com- (see Figure 7). print edit functionality, and up to puter technology groups to meet The 1401 was very successful. By 1,900 magnetic core memory loca- the company’s requirements for 1965, half of the approximately tions for data [1]. However, examin- low cost and high reliability. He 26,000 computers in the world were ing the WWAM circuits more closely, selected the SMS Cube system of 1400-family machines—models 1401, he found that 45% of its electronics packaging and the CTDL circuit 1410, 1440, 1460, and 7010 [2]. The cost was only for communicating family. He also adopted a techno- total number of 1400-family comput- between its plugboard and internal logically advanced chain printer ers peaked at about 15,000 systems logic. An avid proponent of stored- already under development as a in 1967 [2]. Although IBM’s planning program computing, Underwood standalone product for offloading team had not considered the full jettisoned the WWAM’s plugboard mainframe printing (it became the impact of the tape option on custom- and formulated a new instruction IBM 1403). For punched card I/O, ers before the announcement, cus- set for controlling its data paths. He he elected to modify a mainstream tomers soon took advantage of the called his new processor design reader punch unit, the IBM 088. In tape-oriented 1401 systems to replace

34 WINTER 2010 IEEE SOLID-STATE CIRCUITS MAGAZINE

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. the long-term storage of data on end- less numbers of punched cards. For example, Time-Life transferred 40 million punched card subscriber records to just several hundred mag- netic tapes.

Characteristics and Features of the IBM 1401 Most 1401s were leased. Rental for an entry-level system was US$2,500 per month, although very few such systems were installed. The aver- age system typically rented for about US$6,500 per month or cost US$500,000 to purchase (equivalent to US$45,000 and US$3.4 million today)—about a sixth of the purchase price of a large-scale mainframe. Even though the 1401 was consid- ered a small-scale computer, a full-size system had up to half a million discrete FIGURE 7: The IBM 1401 manufacturing and test production line in Endicott, New York, in components, weighed up to four tons, the 1960s. (Image courtesy of IBM Archives.) and consumed up to 13,000 W. The 1401 processing unit used 10,600 ger- holding 8 : a 6- character or 12,000 additional characters of manium alloy-junction transistors and digit, a variable-length data and vari- core memory in a single Cube cabi- 13,200 germanium point-contact di - able-length instruction flag called the net. Core memory was priced at odes on about 2,300 SMS cards inter- “word mark,” and a memory “check about 60 cents per bit (or US$24 connected with 5.5 mi of wire. bit” with odd parity. per byte in today’s currency)—300 The reliability of the 1401 was The 1401’s processor cycle was million times more expensive than renowned, and many systems oper- 11.5 ms, for a clock rate of 87,000 today’s DRAM. ated around the clock. IBM had a large cycles/s. A single character could be Inexpensive magnetic core organization of customer engineers transferred per clock cycle, so the memory was critical to the 1401’s (CEs) who worked closely with users processing speed was well balanced success. Since it was impractical to to maintain their systems. The typical to peripheral I/O rates. Given its dig- drive each of the core memory’s 1401 system was out of service only a it-serial arithmetic, 50 cycles, or ap- half-select X and Y lines with a power few times a year. proximately 0.5 ms, were required to transistor or several transistors as The 1401 processor sequentially add two positive 20-digit numbers. in the transistorized 604, a mag- processed 6-bit characters or decimal Today’s 4-GHz PC can add two 64-bit netic core switching matrix drove digits. A single character or digit was numbers about a million times faster. the memory’s X and Y select lines, stored per memory position, and Assuming today’s currency, a 1401 implementing both address decod- strings of characters or digits could would cost about a thousand times ing and amplification to supply the be arbitrarily long (up to the size of more than a modern PC. This would required one-amp current pulse to memory). Instructions could operate make a PC’s price-performance a bil- the selected memory core. The pro- on two operand strings in memory lion times better than a 1401 when cessor destructively read out core and write the result back into one of doing arithmetic. memory in the first half of an 11.5-µs them. This memory-to-memory in - The 1401 was originally designed cycle; then, in the second half, it struction format, without using an with a 4,000-character maximum restored the previous value or wrote accumulator, reduced program size. It memory capacity but was soon ex- a new value. also reduced processor cost with only panded to 16,000 characters. The Pivotal to the 1401’s success were two operand registers and three first 4,000 characters of memory (in- its robust peripherals. Foremost registers required in cluding a core plane for the punched among these was the IBM 1403 chain hardware logic. Memory ranged in card reader, card punch, and printer) printer. Introduced together with capacity from an entry-level system were located in the 1401 processor’s the 1401, its high speed and enduring with 1,400 positions to a maximum of “main frame” cabinet. The 1406 Op- print quality made it an industry 16,000 positions, with each position tional Storage Unit supported up to workhorse. The 1403 could print up to

IEEE SOLID-STATE CIRCUITS MAGAZINE WINTER 2010 35

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. 132 columns at 600 lines/min, and 1418 was one of the earliest optical to filter out the noisy grid power its hydraulic carriage could skip character recognition (OCR) devices, prevalent around the world. While over blank lines at 33 in/s under the scanning 420 documents/min with large-scale computers generally re- control of a punched carriage con- an OCR algorithm tuned for account- quired cus tom raised-floor and trol tape. Incorporating a new ap- ing machines, the 1403, and Selec- overhead air-exhaust facilities, the proach from IBM’s earlier 150-lines/ tric fonts. The IBM 1428 could read 1401 could be situated in a normal min wheel or stick printers, the 1403 full alphanumeric data in what air-conditioned office or small room, simultaneously fired multiple ham- became the ANSI OCR A font. The with the cables lying on the floor or mers when the proper characters on IBM 1412 Magnetic Ink Character strung overhead. The 1401 contributed to the growth of programming as a profes- sion and software as an industry. Particularly during the 1950s, computer design Thousands of accounting-machine was closely interwoven with rapidly evolving users were retrained as program- mers, and several books covered circuit technologies and techniques. 1401 programming. IBM offered Au- tocoder and Symbolic Programming System (SPS) assemblers for ma- its horizontally revolving chain were Reader (MICR) could read and sort chine-level programming, , in position, slamming the paper, bank checks with digits imprinted COBOL, and report program genera- inked ribbon, and character slug to- with magnetic ink—the ABA E13B tor (RPG) compilers, and sort and gether. Since the human eye does not font seen on the bottom of bank I/O utilities. There was no operating notice minor sideways spacing varia- checks to this day. system for the 1401 (IBM later re- tions between adjacent horizontal To help achieve the low entry- leased one for the 1410). IBM, togeth- characters but is sensitive to vertical level cost, the 1401 processor cabi- er with one of the earliest software misalignment, 1403 printouts were net included controllers for the 1403 user groups, SHARE, offered hun- easy to read. The 1403’s chain assem- printer, 1402 card reader/punch, dreds of privately developed 1401 ap- blies were interchangeable, allowing and optional tape drives. Peripher- plications for multiple industries in the printing of different character als used the processor data paths to business, engineering, mathematics, sets. In order to drive the 1403’s elec- access memory, so instruction pro- and science. tromechanical hammers, a special cessing stopped during most periph- 60-V high-power germanium power eral operations. Later, an “overlap” 1401 Competition and Succession transistor was adopted. feature enabled punched cards to be In late 1963, Honeywell challenged Various models of the IBM 729 read while the processor executed IBM’s market dominance by announc- magnetic-tape vacuum-column drive instructions. IBM provided docu- ing the faster and more capable H200 unit, developed for the 7000-series mentation to enable customers to processor, which had a design simi- mainframes, were able to transfer construct custom interfaces for lar to that of the 1401 (albeit with data at 15,000 to 62,500 char- their peripherals. less robust peripherals). The H200 acters/s, access tape records at 75 The 1401 employed several inter- was offered with so-called “Libera- or 112.5 in/s, and rewind a 2400- esting analog approaches to lower tor” software that could run 1401 foot, 13-million-character tape in costs. The magnetic tape drives programs unmodified and more less than 1 min. Lower-speed IBM transmitted low-voltage tape read quickly than a 1401. The 1401 was 7330 tape drives were also offered. head signals through up to 100 ft of the world’s most popular computer The IBM 1402 Reader Punch Unit daisy-chained single-ended coaxial at the time, and this threat caught could read cards at 800/min and cables to the processor, where the IBM’s management by surprise [11]. punch at 250/min. read amplifiers, dual-level peak de- By that time, IBM was far along in In 1961, the IBM 1405 RAMAC disk tection circuits, and clock recovery orchestrating the succession and drive, with a 20 million character circuits were located. To reduce unification of its many incompatible capacity and an 1800-r/min rota- costs further, the pulses generated computer lines, an effort begun in tional rate, was offered for the 1401. by the 1402’s card reader brushes 1961. That significant planning This was followed in 1962 by the wrote character data over a long effort resulted in the April 1964 IBM 1311 Storage Drive, with remov- cable directly into the magnetic announcement of the System/360 able 2-million-character disk packs. cores in the 1401 frame. To increase (S/360), which consolidated soft- Also in 1961, IBM offered optical reliability, the system employed ware, peripherals, and support in and magnetic bank check readers as ferroresonant transistorized power one compatible and scalable com- peripherals to the 1401. The IBM supplies tuned either to 50 or 60 Hz puter family [11].

36 WINTER 2010 IEEE SOLID-STATE CIRCUITS MAGAZINE

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. One key technology used in the transatlantic transmission of com- printout from a tape-oriented IBM S/360 was a flexible control store puter data via Telstar, the first 1401 used as an I/O spooler for a that implemented the S/360 instruc- commercial communications satellite. large-scale IBM 7090 system. tion set via instructions, IBM engineers using an IBM 1009 enabling the emulation of other Data Transmission Unit on a 1401 in 1401 Restoration Project at the computer instruction sets. When the Endicott and a similar setup in the Le Computer History Museum Honeywell H200 was announced, Gaude lab near Nice, where the IBM Two complete IBM 1401 systems the S/360 Model 30 architects Paris lab had moved, were able to have been brought back to life by a quickly made enhancements to effi- transmit data at 2,000 b/s over a team of about 20 volunteers at the ciently emulate the 1401 instruction voice-grade phone line [13]. Computer History Museum (CHM) in set, thus enabling the Model 30 to hold the fort against the H200 [11]. Although 1400-family develop- Just for fun, the 1401 could play musical ment wound down with the S/360 announcement in 1964, 1400s con- tunes via software that timed the firing of tinued to outnumber S/360s until 1403 print hammers. about mid-1967 [2]. The 1401 was offered by IBM until 1971, and PC- based simulators are still available Just for fun, the 1401 could play Mountain View, California—mostly today. There is a reasonable chance musical tunes via software that IBM engineers who had previously that an IBM mainframe somewhere is timed the firing of 1403 print ham- worked on 1401s in design, test, and still running a 1401 application from mers. Other programs, by executing customer engineering (see Figures 8 decades ago. particular code sequences, modu- and 9). The successful restoration, lated a 1401’s radio wave emissions, after nearly 500 work sessions and 1401 Miscellanea which a nearby AM radio could 20,000 hours [15], highlights the In Endicott, New York, in 1960, Edward easily receive via electromagnetic strength of the 1401’s design and Rent performed an initial analysis of interference (EMI). the reliability of its mechanical and optimal logic card sizes for the IBM The 1401 resurfaced in popular solid-state components nearly 50 1410, the first follow-on to the 1401. culture in 2001 when a young Icelandic years after its manufacture. He measured the ratio of the number composer, Jóhann Jóhannsson, scored In response to a 2004 ad in the of logic blocks in SMS cards in four the symphonic composition IBM 1401: San Jose, California, IBM retirement 1401 chassis gates to the number of A User’s Manual. He had been inspired newsletter, about 20 retired IBM em- card edge signal connectors. The by a 1971 recording of 1401 radio ployees stepped up to the challenge resulting straight-line relationship on music made by his father, a customer of restoring a 45-year-old 1401 ac- a log-log graph was the start of what engineer for Iceland’s first computer, quired from Germany in mostly un- became known as Rent’s rule: Given a 1401, during the machine’s decom- known condition. The CHM acquired the number of logic gates or blocks in missioning ceremony [14]. Jóhanns- a second, 47-year-old 1401 in 2008 a particular circuit, one can calculate son’s composition may be the only from Connecticut that was in better an estimated number of connections human-composed music written for condition. Both systems had origi- or signal pins needed to communi- and dedicated to a computer. nally been operated continuously cate with them [12]. In the 1964 movie Dr. Strangelove, for six and ten years, respectively, In 1964, AT&T, IBM, and the French actor Peter Sellers made his opening by insurance companies; private postal service demonstrated the first appearance examining an IBM 1403 entrepreneurs had then purchased

FIGURE 8: View of the 1401 restoration room at the CHM. The Connecticut 1401 is to the left of center, and the German 1401 is on the right. From left to right: Ron Williams, Don Luke, Joe Preston, Ed Thelen, George Ahearn, Frank King, Glenn Lea, and Bob Erickson (at an IBM 513 Reproducing Punch). An IBM 026 Printing Card and a 077 Collator are to the right. (Photo courtesy of Robert Garner.)

IEEE SOLID-STATE CIRCUITS MAGAZINE WINTER 2010 37

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. FIGURE 9: Members of the 1401 restoration team in period dress. From left to right: Bill Flora, Joe Preston, Sam Sjogren, Jeff Stutzman, Ed Thelen, Bob Feretich, Ron Williams, Frank King, Matthias Goerner, Bob Erickson, Robert Garner, George Ahearn, Don Luke, Allan Palmer, Ron Crane, Stan Paddock, and Bill Newman. (Photo courtesy of Robert Garner.) them to provide billing services IBM 026 card punch. Another was a various peripheral units. The SMS for small businesses. The German 729 tape drive built around card traces with their uncommonly system operated until 1977 and an embedded PC and analog elec- thick gold overcoat, analyzed by was then stored in an outdoor auto tronics used to restore the 1401’s IBM Poughkeepsie’s Materials and garage for 27 years. The U.S. system tape adapter unit (TAU) logic, upload Process Engineering group in 2007, had operated until 1995 in the binaries into the 1401, and emulate have proven extraordinarily reli- air-conditioned basement of a 729 tape drives. able. Nearly all SMS cards were left small residence. Both systems were Remarkably and thankfully, there undisturbed even though the 1401s fully configured with 16,000 have been no problems with the were transported to the CHM via memory locations and four IBM 729 wire-wrap or backplane wires, the trucks and ocean cargo ships and tape drives. IBM’s Almaden Re- long signal wires interconnecting were stored in less-than-ideal envi- search Center and 14 Silicon Valley chassis gates, or the long signal and ronments. Intermittent contact fail- donors generously contributed funds power cable bundles between the ures have been essentially zero for the acquisition of these two nearly 50 years after the date 1401 systems. of manufacture. After acquiring a 60-Hz-to- The 1401 restoration volunteers 50-Hz power converter, restoration analyzed defective components after of the German 1401 proceeded for troubleshooting faulty system be- three years of earnest oscilloscope- havior. A surprising phenomenon and schematic-based debugging. was observed in certain defective The restoration team diagnosed 130 transistors: a “loopy” or hysteretic defective SMS cards. The Connecti- collector current versus voltage cut 1401, mothballed for 18 fewer curve (see Figure 10). This phenom- years than the German system, enon was first reported in the 1950s yielded 25 failed SMS cards. Most and was thought to be caused by of the card failures were due to cor- moist air affecting the germanium roded ferrous transistor and diode surface [16]. The loopy I-V curves leads; weak or leaky transistors; appear in our defective transistor open, shorted, or broken diodes; measurements with collector-emitter and latches acting like one-shots. voltages alternating from 2 Hz up to The number of faulty SMS cards FIGURE 10: A current versus voltage trace 1 MHz, and the effect can persist for corresponded to an annual failure of a defective germanium alloy-junction up to 0.5 s after scanning stops. The rate of only about 0.125% per year, n-p-n transistor, illustrating a hysteresis phenomenon appears to be charac- curve likely caused by a surface inversion. not unreasonable considering high- The I-V curve shows collector-emitter volt- teristic of the “memristor,” first theo - humidity storage. The team located age on the abscissa versus current on the retically defined by Leon Chua in “new old stock” transistors from ordinate at four different base currents. 1971 [17]. In 2008, HP Laboratories Internet sellers. The team also Such “loopy” I-V curves, measured with reported observing memristor hys- designed several new hardware the collector voltage alternating from 2 Hz teresis caused by ionic transport in up to 1 MHz, appear to exhibit “memris- devices. One was a USB interface that tor” behavior, first theoretically defined by thin-film TiOx devices [18]. Perhaps allowed small binary files stored on Leon Chua in 1971 [17]. (Photo courtesy of these defective “loopy” germanium a laptop to be punched directly on an Robert Garner.) transistors were also unknowingly

38 WINTER 2010 IEEE SOLID-STATE CIRCUITS MAGAZINE

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply. exhibiting memristor behavior back Jacobs, Jim Ingram, Jud McCarthy, [15] 1401 Restoration Project Web site. Avail- in the 1950s? John Pokoski, George Ahearn, WWAM able: http://www.ed-thelen.org/1401Proj ect/1401RestorationPage.html designer Maurice Papo, and IBM cir- [16] H. C. Montgomery and W. L. Brown, “Field- cuits pioneer Joseph Logue; comput- induced conductivity changes in germa- Summary nium,” Phy. Rev., vol. 103, no. 4, Aug. 15, Businesses and institutions thro- er historians Fredrick Brooks, Emerson 1956, pp. 866–870. ughout the world used the IBM 1401 Pugh, and Jack Palmer; 1401 restora- [17] L. O. Chua, “Memristor—The missing cir- cuit element,” IEEE Trans. Circuit Theory, in the 1960s to process rapidly tion volunteers and retired IBM test vol. 18, no. 5, pp. 507–519, Sept. 1971. growing amounts of information. and customer engineers Ron Wil- [18] D. B. Strukov, G. S. Snider, D. R. Steward, and R. S. Williams, “The missing memris- By the middle of the decade, one liams, Bob Erickson, Frank King, Allen tor found,” Nature, vol. 453, no. 6932, pp. out of every two computers in the Palmer, Bill Flora, and Don Luke; 1401 80–83, 2008. world was an IBM 1400-family restoration volunteers Ed Thelen, machine, delivering on the promise Grant Saviers, Bob Feretich, and Stan About the Authors of a reliable, cost-effective, high- Paddock; analog expert volunteers Robert Garner received an M.S.E.E. volume transistorized computer. Ronald Crane and Bill Newman; CHM degree from Stanford University in The 1401 heralded a widespread senior curator Dag Spicer; and review- 1977. He started his Silicon Valley transition from plugboard-based ers Ronald Mak, Dick Weaver, Mitchell career at Xerox System Development unit record machines to ubiquitous Marcus, and David Laws. All errors in Palo Alto in 1977. In 1981, he trans- stored-program computing, now and omissions are due entirely to the ferred to the Xerox Palo Alto Research taken for granted with its easy authors’ oversights. Center. In 1984, he joined the start-up sharing and distribution of soft- company Sun Microsystems as the ware applications. The 1401 pro- References lead architect of its SPARC (RISC) vided IBM with the first realistic [1] C. J. Bashe, L. R. Johnson, J. H. Palmer, and architecture and codesigned its first glimpse of the size and importance E. W. Pugh, IBM’s Early Computers. Cam- SPARC product, the Sun-4/200 Work- bridge, MA: MIT Press, 1986. of the computer market and changed [2] E. C. Berkeley, Ed., “Monthly computer cen- station. In 1998, he joined the the world. sus,” Comput. Automat., Dec. 1959–Dec. start-up company Brocade Communi- 1969. Computer History Museum vol- [3] M. H. Weik. (1961, Mar.). A third survey of cations as director of hardware engi- unteers, over the course of the past domestic electronics digital computing neering, where he was responsible systems. Ballistic Research Laboratories, five years, have restored two tape- Aberdeen, MD. Report No. 1115 [Online]. for FibreChannel ASIC and switching oriented IBM 1401s. The operational Available: http://ed-thelen.org/comp- products. In 2001, he joined the IBM hist/BRL61.html systems continue to impress mu - [4] E. W. Pugh, Memories That Shaped an Indus- Almaden Research Center in San Jose, seum visitors and attract new volun- try. Cambridge, MA: MIT Press, 1984. where he codesigned the experimen- [5] J. C. Logue, “Transistor switching cir- teers to keep them running, write cuits,” in Handbook of Semiconductor tal 3-D IceCube server. He currently new demonstration programs, and Electronics, 1st ed., L. P. Hunter, Ed. manages an advanced-redundancy New York: McGraw-Hill, 1956, ch. 15, pp. learn more about the 1401’s elec- 12–13. Petascale storage subsystem soft- tronic and mechanical technologies [6] J. C. Logue, “From vacuum tubes to very ware project. In 2004, he also volun- large scale integration: A personal mem- that are not so miniaturized that oir,” IEEE Annals Hist. Comput., vol. 20, teered at the Computer History they can’t be easily repaired. no. 3, pp. 55–68, July–Sept. 1998. Museum to lead the restoration of an [7] G. D. Bruce and J. C. Logue, “An ex- The Computer History Museum perimental transistor calculator,” AIEE IBM 1401 computer. He can be reached is dedicated to the preservation and Elect. Eng., vol. 74, pp. 1044–1048, Dec. at robgarn@us..com. 1955. celebration of the computing revo- [8] T. J. Leach, “Automated assembly of alloy- lution and its worldwide im pact on junction transistors,” Electronics, vol. 25, Frederick (Rick) Dill first worked for pp. 57–61, Mar. 1960. the human experience. If you have [9] W. Buchholz, Ed., Planning a Computer IBM in 1954 as a summer student and artifacts or stories of the informa- System, Project STRETCH. New York, NY: returned after completing his Ph.D McGraw-Hill, 1962. tion age or are interested in volun- [10] C. J. Bashe, W. Buchholz, G. V. Hawkins, degree in electrical engineering from teering, you are invited to visit the J. J. Ingram, and N. Rochester, “The archi- Carnegie Tech in early 1958, where he tecture of IBM’s early computers,” IBM J. museum in person or its Web site, Res. Develop., vol. 25, no. 5, pp. 363–375, used the IBM 650 vacuum tube com- www.computerhistory.org. 1981. puter. He is a Fellow of the IEEE, former [11] E. W. Pugh, L. R. Johnson, and J. H. Palmer, IBM’s 360 and Early 370 Systems. Cam- president of the Electron Devices Soci- bridge, MA: MIT Press, 1991. ety, and a member of NAE. Most Acknowledgments [12] M. Y. Lanzerotti, G. Fiorenza, and R. A. The first author, Robert Garner, is in- Rand, “Microminiature packaging and in- importantly, he remembers building debted to the first-person insights tegrated circuitry: The work of E. F. Rent,” gallium arsenide transistors with his IBM J. Res. Develop., vol. 49, no. 4/5, pp. and feedback on various parts of 777–803, 2005. own hands trained by the technicians this paper obtained in e-mails and [13] (1964, Oct. 25). IBM Press Release, Endicott, who built the prototypes for the 1401 NY [Online]. Available: http://www.ed-thel- conversations with original 1401 en.org/1401Project/1401Origins.html#IBM- transistors. He was fortunate to live hardware team members Francis Un- Endicott-Nice-Telestar-1964 when the transistor was new and his- [14] J. Jóhannsson. (2005) Available: www. derwood, Charles Branscomb, Sheldon ausersmanual.com tory was happening.

IEEE SOLID-STATE CIRCUITS MAGAZINE WINTER 2010 39

Authorized licensed use limited to: KnowledgeGate from IBM Market Insights. Downloaded on February 5, 2010 at 15:10 from IEEE Xplore. Restrictions apply.