Société D'électronique Et D'automatisme

The Société d'électronique et d'automatisme (SEA) was an early French computer manufacturer established in 1947 by electrical engineer François-Henri Raymond, which designed and put into operation a significant portion of the first computers in France during the 1950s.

The SEA played a major role in driving the development of the French computer industry, training the first generation of engineers and installing about 170 computers between 1955 and its dissolution in 1966, when it merged with CII.

History and achievements

In 1947, François-Henri Raymond is sent for a technical trip to the United States where he meets Howard H. Aiken at Harvard University, visits the MIT laboratories and comes across John von Neumann's report on the EDVAC and the pioneering concepts of a then futuristic machine: the stored-program computer. Upon returning to Paris, he shares his ideas to produce such machines with his employer, a machine tool manufacturer, but struggles to convince him. François-Henri Raymond resignes and, without a formal business plan, establishes the Society of Electronics and Automation in December 1947, in a former automobile factory bombed during World War II. The startup's initial capital is contributed by its founder, some of his friends, and Raymond's former employer. The SEA first client was the Air Force's missile bureau, whose operations demanded significant computational resources.

1949: analog computers

SEA's inaugural computer, the OME 11, emerges in February 1949. This analog computer would set the stage for a series of subsequent models, including the OME 12, 15, 40, and 416 (OME is short for "Opérateurs Mathématiques Électroniques"). While many were tailored for military applications, some models achieved some commercial success in the civilian sector. Notably, the OME L2 and P2 (1952), featuring vacuum tubes, and the transistor-based OME R (1959) stood out and were subsequently followed by a new generation of analog computers with the NADAC 20 (1961) and NADAC 100 (1962).

SEA's analog computers enjoyed commercial success, with nearly 200 units sold and a strong international presence. They found diverse applications in fields such as physical, nuclear, and hydrodynamic simulation - these machines were notably employed for flight simulations of the future Concorde aircraft. SEA also designed tailor-made analog computers for specific military applications.

1951: CUBA

After securing a contract with DEFA (now known as DGA), SEA embarked on the development of its first stored-program computer in 1951, and likely France's first as well: the Calculatrice Universelle Binaire de l'Armement (CUBA). This contract provided SEA the opportunity to bring to life the digital computer plans it had been sketching since 1949.

The then ambitious technological choices made for CUBA would later lead to numerous delays. Notably, the decision to utilize cutting-edge magnetic core memories instead of the more established Williams tubes or mercury delay lines proved risky, as no manufacturer in the still World War 2 recovering French industry was yet capable of producing them. This challenge of sourcing components adhering to a novel set of requirements extended to many aspects, even reaching into wiring - SEA, as stated by its founder, was the first French company to employ ribbon cables and wire wrap.

Among other technological choices, SEA aimed to minimize the use of unreliable vacuum tubes, instead favoring germanium diodes for most of its logic and restricting tube usage to signal regeneration, a design first experimented with the SEAC (see diode logic). Additionally, an auxiliary drum memory was selected to complement the system, which SEA ultimately procured from the British company Ferranti due to the lack of a French manufacturer ready in time.CUBA was eventually delivered in 1954 and put into operation in 1956 after many years of delays, but quickly became obsolete and was abandoned shortly thereafter. By that time, the French computer industry had already witnessed the emergence of other creations: SEA's own CAB 1011, a general computer which was used for cryptanalysis at SDECE (now DGSE), its CAB series 2000 and 3000 computers, and notably the Gamma 3 from Compagnie des machines Bull, introduced in 1952 and sold in quantities of around 1200 units. CAB stood for Calculatrice Automatique Binaire (Binary Automatic Calculator - the term "ordinateur", French for "computer", was coined only in 1955).

The mid-1950s then marked a turning point for SEA, as the company went on to develop two transistorized computers, constituting its two large-scale productions in this field.

1956: CAB 500

Starting from 1956, SEA took an interest in the emerging potential of transistors, although their maturity at that time was yet to be proven. Among the alternatives, SEA explored magnetic logic, which was slower but notably reliable, making it suitable for a more compact-sized computer. In the same year, SEA invented the Symmag, a logic gate utilizing ferrite beads similar to those used in magnetic core memory.

The Symmag would prove to be a central element in the architecture of the CAB 500, alongside a drum memory and sixteen 32-bit registers implemented on magnetic-core memory. The CAB 500 was a compact desktop computer designed to be operated by a single unskilled person, with minimal technical requirements for installation and operation. Furthermore, it was powered by one of the first interactive high-level languages, PAF, which facilitated its usage.

The CAB 500 experienced immediate success, prompting the scaling up of production methods. Approximately a hundred units of the CAB 500 were manufactured and sold, with around a dozen units exported to countries including China and Japan.

1958: CAB 3900

Starting from 1958, SEA became a subsidiary of Schneider-Westinghouse, affording it increased industrial resources. This was also the juncture at which the decision was made to create a business computer, leveraging the experience gained from the CAB 2124 and 3030. Although primarily designed for scientific purposes, these machines were also used for business tasks, revealing a gap in the manufacturer's offerings.

In collaboration with Crédit Lyonnais, the prototype named CABAN (Banking Calculator) was developed, placing emphasis on magnetic tape storage, offering higher capacity compared to punched cards. Intending to compete with the IBM 1401 and the Bull Gamma 30, the CAB 3900 was a fully transistorized machine, featuring a magnetic-core main memory and accommodating up to nine tape drives. It operated at a fairly fast 2 MHz (in contrast, the IBM 1401 was clocked at 870 kHz), which enabled SEA to devise a bit-serial processor, which was less complex and costly while maintaining adequate performance for business applications. The Symmag logic, however, was abandoned as it was deemed too slow.

A programming language called PAGE (Programmation Automatique de GEstion - Automatic Business Programming) was developed for the CAB 3900. It had analogies with COBOL but more limited ambitions and greater simplicity.

In 1963, the French government urged SEA to align with Bull, leading to a negotiated agreement: SEA would allow Bull to market its computer range in exchange for Bull's Andelys plant. This agreement had mixed effects for SEA. On one hand, Bull's sales representatives were not accustomed to catering to scientific needs, resulting in underwhelming sales for the CAB 500. On the other hand, they had to incorporate the competing CAB 3900 business computer into their portfolio alongside their own offerings.

Nonetheless, these newfound production resources enabled SEA to expand its industrial capacity and manufacture the CAB 3900. An improved version, the CAB 4000, was introduced shortly thereafter, rectifying identified flaws from the first generation and enhancing its capabilities.

A total of 37 CAB 3900 and 4000 units were sold, marking the second-largest commercial success for SEA.

Later developments

In 1964, SEA entered into a Memorandum of Understanding with Control Data Corporation (CDC), granting access to the technologies and peripherals of the emerging American supercomputer specialist. However, this agreement did not progress further, as CDC subsequently established its own commercial subsidiary in France. In the same year, IBM unveiled the 360 series, introducing a novel concept of both horizontal (application domains) and vertical (performance levels) compatibility within a unified family of computers. This groundbreaking concept of compatibility and interoperability greatly interested SEA, prompting an exploration of a new generation of products built on these principles. SEA drafted an architecture inspired by stack machines for its processor and Algol for its machine language, similar to Burroughs' approach in the United States. Initially, two models were planned: a successor to the entry-level CAB 500 (CAB 1500) and a high-performance machine for the top tier (CAB 15000). With ambitious plans in mind, SEA contemplated an industrialization program to manufacture approximately a thousand of these new machines.

Ultimately, compelled by the French government in December 1966 as part of Plan Calcul, SEA was forced to merge with Compagnie européenne d'automatisme électronique, a joint subsidiary of Compagnie générale d'électricité, Compagnie générale de télégraphie sans fil (CSF), and Intertechnique, forming the Compagnie internationale pour l'informatique (CII).

At its peak, SEA employed up to 800 staff members and secured nearly 1000 patents.

Marketed models

The SEA primarily produced computers in small quantities, about a couple hundreds, and occasionally as one-of-a-kind units, most notably for military clients.
Six major categories of computers stand out:

* Analog computers, from the OME and NADAC family
* Unique military models, such as the CUBA and CAB 1011
* The CAB 2000 and 3000 families, which were the first mass produced stored program computers from SEA
* Business computers (CAB 3900 and 4000)
* The CAB 500, a relatively different small computer in the range
* And finally, research prototypes: the Dorothées, CAB 1500 and 15000

The following table provides an overview of the key digital computers constructed by SEA. The analog calculators from the OME and NADAC series are not included in the representation, neither are specific, non commercial units such as the CUBA.

See also

* List of vacuum tube computers
* History of computing

References

{{reflist

External links

History of SEA, on the Bull Teams Federation (FEB)


from François-Henri Raymond, extract from ''Colloquium on the History of Computing in France'', March 1988


* ttps://www.analogmuseum.org/library/OME-P2.pdf 1955 review of the OME P2 analog computer(in French)

Description of the symmag magnetic logic used in the CAB-500
(in French)

Illustrated SEA presentation brochure
from the "Birth of the French computing industry" exposition, in French

History of computing
History of computing in France
Defunct computer hardware companies
Defunct computer systems companies
Computer companies of France