We are used to thinking that the history of microprocessors begins with the Intel 4004. Even those who are not experts associate it with it as the first great chip that inaugurated the era of personal computing. But that is not the only possible story. There was another design, less known and outside the commercial circuits, that began operating before the 4004 reached the market. It did not appear on a computer or calculatorbut in an F-14 Tomcat, and for almost thirty years he was invisible to the public.
What that plane had inside was a processor designed to do something that no commercial chip did at that time: automatically calculate speed, altitude or wing position while the pilot maneuvered. That system, known as MP944, had been in service since 1970, when the 4004 had not yet been introduced. Its context was completely different from that of Intel, because it was not designed for the market or to be licensed, but rather to fulfill a requirement of the military program marked by the tensions of the Cold War.
A secret microprocessor in the bowels of an F-14
The novelty was not only that it made calculations, but that it did so automatically and digitally, something unusual in on-board systems from the late sixties. The MP944 processed sensor readingsapplied aerodynamic equations and provided data that influenced the behavior of the plane, reducing the pilot’s workload. It was not a passive assistant, but a module capable of interpreting those readings and providing results fast enough to be integrated into actual flight control. That is why it was considered a technology ahead of its time.
Documents declassified in the 1990s show that the MP944 combined advanced MOS technology with a 20-bit parallel architecture capable of executing pipelined calculations, something unusual for its time. Its frequency was 375 kHz and it could process specific mathematical operations efficiently enough to be integrated into real flight systems. According to the figures collected in Holt’s work and in the subsequent review by Tom’s Hardware, this performance placed the MP944 clearly ahead of the 4004 in number of instructions executed, although it was never intended as a general-purpose commercial chip. They were two different approaches: one for a military aircraft, the other for a commercial device.
When Holt’s work came to light decades later, he argued that the MP944 should be considered the first microprocessor, even though it was not on a single chip or commercially available. Intel engineers, such as Ted Hoff and Federico Faggin, disagreed and argued that 4004 was the first in integrating all the essential functions of a CPU in a single piece of silicon and with general use. Russell Fish, a former Motorola engineer, reviewed the MP944 documentation and described it as an advanced microprocessor for its time, while Richard Belgard saw it as an overly specific system, designed only to keep an airplane in flight.
Holt maintained that the reason no one knew about MP944 for years was because his work had been classified and subject to military restrictions. He said he spent decades requesting the release of the documents and was only able to do so when, in 1997, he won the support of Congresswoman Zoe Lofgren for the Navy to authorize their publication. With the documentation now available, the Navy qualified that version and maintained that Holt’s work had not actually been classified, but that what was missing was the company’s authorization to release the records. Garrett AiResearch admitted that they were no longer clear about what had happened, because the people who managed the case had left the company.
When the information became available, Russell Fish claimed that MP944 was so advanced for its time that, if known, it could have accelerated the development of the sector by up to five years. The creators of the 4004, such as Federico Faggin and Stan Mazor, openly disagreed and pointed out that the merit of the commercial microprocessor was to integrate all the essential elements on a single chip and make it viable for multiple applications. Richard Belgard qualified this position: he recognized the technical value of the MP944, but saw it as a system designed for a single purpose, without the capacity to open its own market.
The debate about which was the first microprocessor is not resolved with a date, but with a definition. The 4004 was the first to hit the market as a commercial, integrated and programmable chip, and that merit explains its place in manuals. The MP944, on the other hand, previously demonstrated that it was possible to process data digitally and feed control systems in real time, even if it was done while locked in an airplane and outside of public space. One opened an industry; the other anticipated capabilities. Both represented different ways of understanding what a microprocessor could be.
Images | DVIDS (1, 2, 3) | Thomas Nguyen
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