Ohio Scientific

Ohio Scientific, Inc.
	File:Ohio Scientific wordmark.svg
Formerly	Ohio Scientific Instruments, Inc. (1975–1979); M/A-COM Office Systems, Inc. (1981–1983);
Company type	Private
Industry	Computer
Founded	1975; 51 years ago in Hiram, Ohio
Founders	Michael Cheiky; Charity Cheiky; Dale Dreisbach;
Defunct	Template:End date and age
Fate	Acquired by M/A-COM in 1980; later sold to Kendata in early 1983, then Isotron, Inc. (AB Fannyudde [sv]), in late 1983, then Dataindustrier AB in 1986
Headquarters	Aurora, Ohio, United States
Products	See § Products
Number of employees	300 (1980, peak)
Parent	M/A-COM (1981–1983); Kendata (1983); Isotron, Inc. (1983–1986);

Ohio Scientific, Inc. (OSI), initially known as Ohio Scientific Instruments, Inc., was a privately held American computer manufacturer headquartered in Ohio that operated from 1975 through 1986. The company specialized in producing computer hardware, expansion modules, and software solutions. Its most recognized product lines included the Challenger microcomputer series and the Superboard single-board computers. Notably, OSI was a pioneer in introducing microcomputers equipped with hard disk drives as early as 1977.

The firm was founded in 1975 in Hiram, Ohio by entrepreneurs Mike Cheiky, Charity Cheiky, and Dale A. Dreisbach. Originally concentrating on electronic educational tools, OSI quickly shifted its focus toward microcomputer manufacturing after the educational product line underperformed while computer-related items attracted considerable enthusiasm from hobbyist markets. The company expanded operations into a 72,000-square-foot facility located in Aurora, Ohio, achieving revenues of $1 million by 1976 and growing to $18 million by 1980. Manufacturing activities were distributed across locations in Ohio, California, and Puerto Rico.

In 1980, OSI was purchased by the telecommunications giant M/A-COM for $5 million, which rebranded the company as M/A-COM Office Systems and concentrated its efforts on producing business-oriented systems. However, financial setbacks at M/A-COM resulted in the sale of OSI to Kendata Inc. in 1983. Kendata restored the original Ohio Scientific name but struggled to maintain production operations. Subsequent ownership changes transferred the company to Sweden’s AB Fannyudde and later to Dataindustrier AB. The manufacturing plant in Aurora ceased operations in October 1983 following staff reductions.

Beginnings (1975–1976)

Ohio Scientific was founded in 1975 by Dale A. Dreisbach (circa 1909–1987), Michael "Mike" Cheiky (1952–2017), and Charity Cheiky (born approximately 1954). Mike brought engineering expertise from his tenure at Ohio Nuclear Company; Charity contributed her academic background from Western Reserve Academy; Dreisbach was a retired chemistry professor from Hiram College. The initial capital investment ranged between $5,000 and $25,000.

Starting out from the Cheikys' garage under the name Ohio Scientific Instruments, Inc., the enterprise initially targeted electronic teaching aids but soon pivoted after local sales of these products were disappointing. Early product offerings comprised a statistics tutorial calculator and a single-board microcomputer called the Microcomputer Trainer Board—powered by a MOS Technology 6502 microprocessor—designed by Mike leveraging his experience with minicomputers.

The Trainer Board achieved rapid market acceptance through focused advertising campaigns in Byte, generating orders totaling $100,000 within several months and achieving sales of $20,000—far surpassing initial projections. To support this growth trajectory, OSI relocated to a 700-square-foot retail space in Hiram situated near other local businesses.

Expansion Phase (1976–1980)

Following the introduction of their microcomputer products in the mid-1970s, Charity Cheiky became the pioneering female leader of a personal computer manufacturing company. By June 1976, Ohio Scientific had achieved $1 million in sales. In January 1978, the company moved from Hiram to a 72,000-square-foot facility in Aurora, Ohio, increasing its staff from 35 to 100 employees within half a year. Revenue escalated swiftly, reaching $10 million between 1977 and 1978, and doubling to $20 million by 1980. That year alone, Ohio Scientific recorded $18 million in revenue.

The Cheikys believed the rapid growth was becoming difficult to control effectively. Business associate Stan Veit characterized Ohio Scientific as lacking sufficient capital and proper organization, with delayed delivery schedules that limited sales despite their strong technical expertise. To tackle dealer complaints regarding slow software development, the company introduced a centralized software dealership initiative in late 1978 aimed at speeding up the creation of business applications.

In 1980, Ohio Scientific broadened its operations by inaugurating a manufacturing plant along with a 15,000-square-foot sales training center in Cleveland. Concurrently, they launched a printed circuit board production facility in Puerto Rico, establishing Ohio Scientific of Puerto Rico, Inc. Later that year, in November, Ohio Scientific acquired Okidata’s hard drive manufacturing unit located in Goleta, California, integrating it into their Ohio Scientific Memory Products division to supply storage drives for their Challenger microcomputers. By this stage, the company employed roughly 300 personnel across all locations.

Acquisition Period (1980–1983)

Although Ohio Scientific worked to enhance its software portfolio, it continued to face challenges with timely software delivery. Looking for an exit strategy, the Cheikys engaged with M/A-COM, a telecommunications conglomerate headquartered in Burlington, Massachusetts. In November 1980, M/A-COM announced its intention to purchase Ohio Scientific for $5 million in cash—with $3 million paid to the Cheikys and the balance going to Dreisbach. The acquisition was finalized in December 1980 with financial support from McDonald & Co. of Cleveland. Irwin M. Jacobs, president of M/A-COM, described the acquisition as part of a broader plan to offer integrated office communications solutions.

M/A-COM took ownership of all Ohio Scientific facilities located in Ohio, California, and Puerto Rico. The Cheikys briefly remained as consultants but were soon dismissed due to strategic disagreements. Harvey P. White initially managed the subsidiary before transferring to lead M/A-COM's Linkabit division; William Chalmers succeeded him after interim president Doug Hajjar's tenure. Chalmers was chosen over Chuck Kempton, a marketing vice president recruited from Wang Laboratories.

Under M/A-COM's control during 1981, Ohio Scientific experienced major corporate restructuring. Although the Aurora headquarters remained nominally active, most research and development activities were transferred to Burlington early in 1982; additionally, a second R&D center was established in California under Mike Cheiky’s leadership. Chalmers also relocated to Burlington. In December 1981, the subsidiary was renamed M/A-COM Office Systems, Inc., reflecting a strategic departure from its original brand identity. Chalmers remarked in 1982: "This is not an Ohio or a scientific company any more." The product line was dramatically reduced from 110 hardware and software offerings to seven primary business systems with customizable configurations. Future developments concentrated on Intel 8088 processors running CP/M-86 operating systems.

Demise (1983)

In August 1982, M/A-COM declared its intention to divest M/A-COM Office Systems by the end of the year, attributing this decision to a strategic shift toward high-speed digital communications and escalating development expenses associated with general-purpose hardware and software. The parent company was also contending with substantial financial losses.

By February 1983, Kendata Inc., a corporate reseller specializing in Victor computers and headquartered in Trumbull, Connecticut, acquired M/A-COM Office Systems. Kendata promptly reinstated the subsidiary’s original name, Ohio Scientific, aiming to capitalize on its established market reputation. Despite this, Kendata encountered significant difficulties related to manufacturing and technical issues, compounded by fierce competition from industry giants IBM and Tandy Corporation.

On October 3, 1983, the Aurora manufacturing facility of Ohio Scientific was shut down and its inventory liquidated following Kendata’s foreclosure on the property. This action led to the dismissal of the remaining 16 employees and effectively ended Aurora’s role as a hub for high-technology manufacturing.

In December 1983, Kendata sold the residual assets of Ohio Scientific to Sweden-based AB Fannyudde, which subsequently incorporated the company into its Isotron, Inc. subsidiary. Ohio Scientific continued operations under Isotron until 1986 when Dataindustrier AB (DIAB) purchased Isotron from Fannyudde.

Model 300 Computer Trainer Board (1976)

Ohio Scientific gained recognition primarily through its Superboard and Challenger series, which included both single-board computers and complete microcomputer systems housed in enclosures. The initial Superboards were introduced in the December 1975 issue of Byte. Prior to these releases, Ohio Scientific launched the Model 300 Computer Trainer Board featuring an MOS Technology 6502 CPU along with 128 Bytes of RAM. The compact board measured and required an external power supply delivering 5 V DC at 500 mA.

This trainer board was designed in line with contemporaneous educational boards; slide switches located on its underside connected directly to the 6502 processor’s data lines, read/write controls, and address pins. This setup allowed users to halt processor activity and manually input machine code into RAM. A set of LEDs provided visual feedback on the processor’s bus activity. Ohio Scientific supplied these units fully assembled along with documentation; power supplies and programming manuals were available as optional purchases.

Model 400 Superboard (1976)

September 1976 saw the release of the Model 400 Superboard by Ohio Scientific as a kit for self-assembly. This system supported multiple CPUs including the MOS 6502, MOS 6501, or Motorola 6800 processors. Its architecture featured a 48-line wide bus designed for backplane expansion, facilitating connection to peripheral cards such as the Model 420 memory expansion, Model 430 Super I/O board, and Model 440 Super Video graphics board. The Model 400 accommodated up to 1 kB of RAM and included 512 bytes of ROM, an ACIA chip for RS-232 or 4–20 mA loop serial communication interfaces, plus a peripheral adapter offering sixteen input/output lines. Constructed from G-10 fiberglass laminate material, the board measured approximately 8 by 10 inches.

The Model 430 Super I/O card provided two separate 8-bit digital-to-analog converters (DACs), one 8-bit analog-to-digital converter (ADC), an eight-bit parallel port, as well as multiple serial ports compatible with terminal and teletype communication protocols such as Baudot and ASCII. In 1977, Ohio Scientific introduced a rental option known as the "315 plan," enabling customers to upgrade from the Model 300 Trainer Board to a full Model 400 system complete with peripheral expansions.

In August of that same year, Ohio Scientific unveiled the OSI 460Z multiprocessor expansion board kit designed specifically for the Model 400 Superboard. This addition broadened software compatibility by supporting additional CPUs such as the Intersil 6100 (an implementation akin to the PDP-8) and Zilog Z80 (compatible with Intel’s 8080). The OSI 460Z functioned exclusively when paired with Model 400 units running a MOS 6502 processor, which acted as the primary controller for the expansion board and could regulate secondary processors by switching them between single-step or continuous operation modes. This configuration enabled genuine multiprocessing capabilities by allowing multiple processors to execute code concurrently through interrupt-driven context switching. When equipped with the OSI 460Z board, the Model 400 accessed other expansion cards via a designated mapped memory region—a "porthole"—of four kilobytes within the expansion’s address space.

Challenger I (1976)

Ohio Scientific unveiled its initial Challenger computer system, later designated as the Challenger I, around November 1976. Promoted as a compact tabletop computer, it utilized much of the circuitry from the Superboards but introduced a unique 48-pin S-100 bus featuring four expansion slots with Molex connectors. This design aimed to enhance reliability and facilitate future upgrades. The bus architecture included bi-directional data lines and fully regulated DC power, providing an economical and efficient method for system expansion.

The standard configuration was equipped with a 1-MHz MOS 6502A microprocessor, with optional enhancements available for a 4-MHz MOS 6502C or a Motorola 6800 processor. It came with 1 KB each of RAM and PROM, expandable to a maximum of 192 KB RAM and 16 KB PROM. Buyers who selected 4 KB of PROM were granted Microsoft BASIC on paper tape at no additional cost.

Equipped with an integrated bootstrap loader compatible with paper tape readers such as the Teletype Model 33, the Challenger I also supported video terminal connections. By mid-1977, Ohio Scientific expanded its product line for the Challenger I to include peripherals like single or dual floppy disk drives manufactured by GSI, cassette drives, video interface cards, and external keyboards. In January 1978, the company introduced a bundled package combining the Challenger I with a custom Sanyo CRT terminal, a rebranded GSI floppy drive, and Okidata dot-matrix printers.

Kilobaud Microcomputing described the Challenger I as "the first fully assembled mainframe computer priced competitively with hobby kits," underscoring Ohio Scientific's strategy to serve both hobbyists and professional markets through affordable and scalable computer systems.

Ohio Scientific Model 500 (1977)

Introduced in July 1977, the Ohio Scientific Model 500 was available in three configurations: a single-board computer, a compact desktop version (Model 500-1), and a keyboard-integrated model (Model 500-8). Powered by a 1-MHz MOS 6502 microprocessor, it supported up to 4 KB of RAM and included a 750-byte PROM along with four ROM sockets capable of holding up to 8 KB of ROM chips. The four included 2-KB ROM chips contained Microsoft's official BASIC interpreter. The Model 500 also featured a buffered expansion bus and incorporated a Motorola 6850 UART to support RS-232 and current-loop serial communication protocols.

The dimensions of the Model 500-1 measured approximately 12 by 15 by 4 centimeters, while the keyboard-equipped Model 500-8 was sized at roughly 15 by 17 by 10 centimeters. Fully assembled upon delivery, it maintained compatibility with Ohio Scientific’s Model 400 peripherals through the same backplane system, including support for the Model 440 Super Video board. Two machine code monitors were provided: one designed for terminal video output and another intended for use with the Model 440 video board.

From a market positioning perspective, the Model 500 was priced competitively against the "1977 Trinity"—Apple II, Commodore PET, and TRS-80—offering Microsoft BASIC at a noticeably lower price point. Although it was not marketed as a turnkey appliance computer, it attracted hobbyists willing to engage in more hands-on setup. This model exemplified Ohio Scientific’s commitment to delivering cost-effective computing solutions tailored to early microcomputer enthusiasts and small-scale users.

Challenger II, 2P (1977)

Introduced in 1977, the Challenger II family encompassed several models and configurations. The earliest versions—the Challenger II (initially model IIV, later known as C2-S2) and the Challenger IIP—were constructed around Ohio Scientific's Model 500 single-board computer. The Challenger IIP was powered by a 2-MHz MOS 6502A CPU, whereas the Challenger II operated with a slower 1-MHz 6502 processor. The IIP came equipped with an integrated keyboard and RF video output but offered only four semi-proprietary S-100 expansion slots. Conversely, the II provided eight S-100 slots but lacked both a keyboard and video output, instead relying on an external terminal and adopting a desktop design. Initially, the II did not include the cassette interface found on the IIP. Both systems shipped with Microsoft BASIC (with the IIP’s version stored in ROM), contained 4 KB of RAM, and maintained compatibility with all software designed for the original Challenger I. Subsequent II models incorporated the IIP’s cassette interface and video board along with an external full-sized keyboard.

The video output on the IIP was limited to text mode (32 rows by 64 columns) delivered via RF signal; simple graphics could be generated using special characters and customizable character sets. Starting in May 1978, Ohio Scientific offered the IIP’s built-in video board separately as the Model 540 for use with other Challenger units.

In November 1977, Ohio Scientific unveiled the C-D74 external hard drive, which utilized a 14-inch, 74-MB Winchester disk manufactured by Okidata—the first hard drive for microcomputers to feature 12 tracks per cylinder, eliminating head reseeking delays. This device achieved a data transfer rate of 7.3 Mbit/s, an access time of 5 milliseconds, and an average seek time of 35 milliseconds. Engineered specifically for the Challenger series, it came with OS-74 operating system support and an S-100 interface card. Later integrated into the Challenger III rack system, this innovation established Ohio Scientific as a pioneer in delivering microcomputers equipped with hard drives.

By April 1978, variants of both the II and IIP models were introduced featuring external 8-inch floppy disk drives; these "unbundled" systems were sold without external enclosures or power supplies. In 1979, Ohio Scientific expanded its offerings with an external dual 5.25-inch floppy drive unit compatible with the Challenger II. From September 1977 onward, all Challengers featuring floppy drives included OS-65D—a proprietary disk operating system providing filesystem support alongside BASIC, assembler/disassembler utilities, a line editor, and debugger—designed to use no more than 12 KB of RAM through overlay techniques. OS-65D supported dual floppy drives and enabled both sequential and random file access modes, significantly enhancing these systems' appeal for business applications.

Challenger III (1977)

Released concurrently with the Challenger II in 1977, the Challenger III was a desktop microcomputer incorporating three different processors—a MOS 6502A, a Zilog Z80, and a Motorola 6800—on a single circuit board. This multi-CPU design allowed it to run nearly all microcomputer software available at that time. Although only one processor could operate at any given moment, software interrupts facilitated smooth switching among them.

Ohio Scientific marketed the Challenger III as an ideal development platform for computer science students, a unified solution for small businesses or industrial users requiring multiple computing environments within one device, and as an advanced option for hobbyists. Optional accessories included an external dual 8-inch floppy drive and the C-D74 hard drive unit. These components were combined into the rack-mounted C3-B system—the first microcomputer to feature an integrated hard drive solution. By 1979, a lower-capacity version with a 24 MB hard disk was introduced.

The C3-B proved particularly effective as a database management system supporting multiple client terminals through its CA-10 serial I/O board, which could connect up to sixteen terminals simultaneously. In late 1978, Ohio Scientific launched the C3-OEM variant of the Challenger III that incorporated both the CA-10 board and dual floppy drives but omitted an integrated keyboard.

This product range highlighted Ohio Scientific’s strategic foresight in delivering versatile computing platforms that bridged educational environments, business needs, and industrial applications—strengthening their market position and competitive edge within the microcomputer industry.

Superboard II, Challenger 1P (1978)

Introduced in the autumn of 1978, the Superboard II was equipped with a MOS 6502 CPU, featuring 8 KB of BASIC stored in ROM, alongside separate ROMs for BIOS and a machine code monitor. It included 8 KB of static RAM, a cassette interface, and an integrated keyboard directly soldered onto the mainboard. Ohio Scientific marketed this model as the first microcomputer to integrate all components onto a single circuit board due to its unique design approach. Alongside it debuted the Challenger 1P, essentially the same hardware housed within a case that incorporated an internal power supply. Optional enhancements offered users 24 KB of RAM and a floppy disk controller capable of managing two 5.25-inch drives as well as connections for printers or modems.

The Superboard II's dimensions were compact, and it minimized component count by utilizing advanced large scale integration (LSI) chips that consolidated multiple support functions into individual ICs. The assembly process involved hand-soldering all 57 integrated circuits, passive components, keyboard parts, and a fuse; notably, the board lacked both solder mask and printed legends. A British version of this system was sold under the name Compukit UK101.

Bruce S. Chamberlain from Kilobaud Microcomputing commended its rapid BASIC interpreter and described it as "more affordable than comparable alternatives" and "the best value for novices and experts alike," emphasizing its cost-effective upgrade path. Similarly, Christopher Morgan of Byte magazine regarded it as "an outstanding option for budget-conscious personal computing enthusiasts."

Challenger 4P (1979)

Released in late 1979, the Challenger 4P was a keyboard-based computer powered by the 6502 microprocessor. It marked the first model in the Challenger series to support native color graphics, capable of displaying up to 16 colors simultaneously in bitmap mode and providing text resolution of 64 columns by 32 rows. Retaining features from earlier models, it allowed user-defined characters that enabled sophisticated shapes even within text mode displays. The system came standard with 24 KB of RAM expandable up to 48 KB and included a DAC interface facilitating sound production, voice output, analog joystick input, and notably, home automation control.

The 4P incorporated the X10 protocol, an industry standard for home automation at the time, enabling users to manage up to sixteen lighting fixtures and appliances through dedicated software. Its background mode supported multitasking by running additional programs concurrently while a resident timer managed scheduled control of connected devices. This fusion of computing power with home automation capabilities illustrated Ohio Scientific’s pioneering approach in targeting the emerging smart home sector.

C1P (MF) Series II (1980)

The C1P Series II represented an updated version of the Challenger 1P, featuring a plastic outer shell mounted on a metal chassis and integrating the DAC sound capabilities introduced with the Challenger 4P for enhanced audio and music performance. It came equipped with Microsoft’s 8K BASIC in ROM along with 8 KB of static RAM. Expansion options included the 630/10 card that provided home automation features comparable to those found on the 4P model. The C1P MF variant bundled dual 5.25-inch floppy disk drives alongside OS-MDMS, a compact database management system designed to appeal to business users requiring efficient data handling solutions.

This product range underscored Ohio Scientific’s commitment to delivering adaptable computing platforms combining multimedia and automation functions tailored for both consumer and enterprise markets, promoting business expansion through diversified offerings.

External links

Archive of Ohio Scientific and Compukit materials maintained by Mark Spankus
osiweb.org – Forum and repository dedicated to Ohio Scientific