Electronic Arrays 9002

[...] "Sales had reached $100,000 per month when this advertisement ran in March 1973.

Ed Roberts' interest in computers began in high school when he built a simple digital computer from relays. His first real experience with computers came while at Oklahoma State University where engineering students had free access to an IBM 1620 computer. Roberts' office at Weapons Laboratory had the state of the art Hewlett-Packard 9100A programmable calculator in 1968. In July 1970, a semiconductor company, Electronic Arrays, announced a set of six LSI ICs that would make a four-function calculator.[22][23] Roberts was determined to design a calculator kit.

To fund the new project, Roberts sold 15% of MITS to fellow Air Force officer, Lieutenant William Yates. He also got an investment from another Weapons Laboratory officer, Major Ed Laughlin. Several other officers and scientist at the lab were interested in this state of the art calculator kit and helped with the design. Forrest Mims wrote the assembly manual in return for a calculator kit."

[...]

• "New Products: Do-it-yourself Electronic Calculator". Computer. IEEE. 3 (6): 38–41. November 1970. doi:10.1109/C-M.1970.216730. Electronic Arrays has developed the EAS100, a set of MOS LSI circuits for a 16 digit calculator with 8 digit display capability.
• ^ US patent 3800129, Richard H. Umstattd, "MOS Desk Calculator", issued 1974-03-26 The Electronic Arrays, Inc. calculator chip set that was used in the MITS 816 calculator.

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Short news release announcing the publication of an article in Popular Electronics magazine introducing the MITS 816 electronic calculator kit, based on the Electronic Arrays S-80 six-chip MOS large-scale integration calculator chipset. The S-80 chipset contained a change to the microcode of Electronic Arrays' original S-100 chipset that provided a different means for setting the decimal point position.

The MITS 816 has significant historical significance, as it was the first electronic calculator to be offered as a kit that anyone with a modicum of electronics skills could put together themselves."

In the world of electronic calculators, the company named MITS may not ring bells for many people. However, those who were involved in the infancy of personal computing, or those who have an affection for the early days of personal computing know the name well. MITS, (pronounced letter at a time) is an acronym for Micro Instrumentation and Telemetry Systems, effectively created the "personal computer" market with the introduction of the "Altair 8800" mini-computer (as they called it) in early 1975. The Altair computer was heralded as a breakthrough in the world of computers, with a kit selling for a mere $397 in 1974. There were other "hobbyist" computers available at the time, but they were not as powerful (relying on earlier microprocessor chips), nor as well publicized as the Altair. The Altair computer was featured on the front cover of the January, 1975 edition of Popular Electronics magazine, with a series of articles on the design and construction of the machine. Orders for the Altair poured in at a tremendous rate, propelling MITS and the Altair into the spotlight of personal computer history.

MITS started up as a small four-man company in late 1969. The principals were Ed Roberts, Forrest Mims III, Stan Cagle, and Bob Zahler. In January of 1970, the company was formally incorporated. Initial discussions came to the conclusion that there was a market in the model rocketry field for various electronic devices to go up with the rocket, at first, strobe lights to aid in recovery (for night launches), and later, to provide simple radio telemetery. These devices were designed such that hobbyists could build them from a kit, or buy pre-assembled. Later, MITS developed a novel wireless "walkie talkie" that used a beam of infrared light to send voice between two transceivers, up to 1000 feet apart.

While these products generated a modest revenue, by the early part of 1971, MITS was looking for a way to break into new markets. At the same time the fledgeling Large-Scale Integration (LSI) MOS Integrated Circuit manufacturer, Electronic Arrays, had recently introduced a six-device chipset that provided a great majority of the logic for a complete four-function electronic calculator. In mid-1971, the MITS team realized that there was tremendous market potential for low-priced electronic calculators. MITS contacted Electronic Arrays to arrange for some production samples. Soon, a prototype machine was built. MITS arranged volume pricing of the chipset, further reducing the cost. Since MITS had experienced some earlier success with Ed Roberts and Forrest Mims writing articles for various hobbyist publications, especially Popular Electronics, it was hoped that the calculator could make its debut as a featured construction article in that publication. Popular Electronics was contacted, and shown the prototype of the calculator in the fall of 1971.

The calculator was a big hit with the magazine's publishers(Ziff-Davis), and made the cover of the November, 1971 issue of the magazine, with the lead story proclaiming "Electronic Desk Calculator You Can Build". At the time, the machine was called the "Popular Electronics Calculator", but internally to MITS, this machine was designated as the model 816. The 816 could be ordered as a complete, assembled calculator for $275, or as a ready-to-build kit for $179. The model number 816 was based on the fact that the calculator had an eight-digit vacuum-fluorescent display, but could perform calculations to sixteen digits. At the time, the major players in the calculator market were charging between $400 and $600 for an electronic calculator with similar functionality.

The Electronic Arrays chipset consisted of six LSI integrated circuits containing over 8,000 transistors. The six devices had specific functions; input(keyboard processing), output(display generation), arithmetic(math processing), register storage, control ROM(microcode), and control logic. While it isn't entirely clear at this time, the chipset used in the MITS 816 appears to be the same chipset used in the ICM-816 calculator, which was introduced by a subsidiary of Electronic Arrays called International Calculating Machines, in early 1971. The ICM 816 initially sold for $495.

MITS proceeded to develop a number of other desktop (908DM and 1440), and later, handheld calculators which were sold as kits or fully-assembled. While the calculator line was initially successful, the intense competition in the marketplace, along with the introduction of single-chip calculator IC's by various large chip makers such as Texas Instruments, Rockwell and General Instruments, made it difficult for MITS to remain price-competitive in the market. There was also tough competition in the electronics kit market from Heathkit, who offered a number of high-quality build-it-yourself calculator products. By the late part of 1973, it was possible to buy a mass-market calculator fully assembled, for less than it cost to buy one of MITS 816, 1440, or 908DM desktop calculator kits.