IBM’s System/360: The Groundbreaking Mainframe That Helped Land Men on the Moon

54 years ago, IBM introduced the groundbreaking System/360 mainframe, which played a vital role in NASA’s Apollo missions and revolutionized computer compatibility. This innovative technology allowed machines within a product line to communicate and work with each other, setting new standards in the computer industry.

A New Era of Compatibility

Before the System/360, businesses would purchase a computer, develop programs for it, and eventually discard it when it became outdated or slow. IBM’s System/360 changed this by introducing compatibility across a family of machines, saving businesses from the costly endeavor of rewriting essential programs. This product line featured upward compatibility with larger processors and ensured peripherals like printers and storage devices were compatible as well.

The Launch of System/360

IBM announced the System/360 in April 1964, with prices ranging from $133,000 to $5.5 million or rental fees between $2,700 to $115,000 a month. The excitement around the new product line was palpable, as more than 100,000 businessmen attended meetings announcing the System/360 in 165 American cities. IBM President Thomas J. Watson Jr. hailed the System/360 as IBM’s most important product announcement ever, marking a significant departure from previous computer design concepts.

Impressive Specifications and NASA’s Apollo Missions

Late 1960s: NASA's IBM System/360 Model 91 operator console in action. IBM System/360. (2023, February 2). In Wikipedia. https://en.wikipedia.org/wiki/IBM_System/360
Late 1960s: NASA’s IBM System/360 Model 91 operator console in action. Credit: IBM System/360. (2023, February 2). In Wikipedia. https://en.wikipedia.org/wiki/IBM_System/360

The System/360’s impressive specs included the introduction of the 8-bit byte, a performance range of 25-to-1, and processing speeds ranging from 33,000 to over 750,000 additions per second. These machines played a crucial role in NASA’s Apollo missions, translating the massive amounts of data sent by Apollo flights into useful information for flight controllers.

The same System/360 computer that processed the data for the first lunar landing also calculated the liftoff data needed for astronauts Neil Armstrong and Buzz Aldrin to rendezvous back with the command module piloted by Michael Collins for the flight back to Earth.

IBM’s Continued Mainframe Evolution

The IBM Real-Time Computer Complex (RTCC) at NASA's Houston-based Manned Spacecraft Center (now Lyndon B. Johnson Space Center) rapidly processed and relayed data for directing Apollo missions. Initially utilizing IBM 7094-11 computers, the RTCC later employed IBM System/360 Model 75J mainframes and related storage and processing equipment.
The IBM Real-Time Computer Complex (RTCC) at NASA’s Houston-based Manned Spacecraft Center (now Lyndon B. Johnson Space Center) rapidly processed and relayed data for directing Apollo missions. Initially utilizing IBM 7094-11 computers, the RTCC later employed IBM System/360 Model 75J mainframes and related storage and processing equipment.

In the early 1970s, IBM started replacing the System/360 with the System/370, maintaining its dominance in the computing market. Today, IBM mainframes remain a significant business, generating $1.1 billion in revenue in the most recent quarter.

IBM’s modern mainframes, known as System z, maintain compatibility with their predecessors, all the way back to System/360. This compatibility requirement demands strict design considerations for new hardware and software, ensuring that applications continue to work properly.

As a testament to the lasting impact of the System/360, programs developed for the original machines can still run, sometimes with minor modifications, on modern IBM mainframes. IBM remains committed to providing users with ample notice before any necessary software changes, preserving the legacy of the groundbreaking System/360 mainframe.

A Lasting Legacy: System/360’s Impact on Modern Computing

The Saturn digital computer, developed by IBM's Electronics Systems Center in Owego, NY, was integral to the launch vehicle guidance system. It managed prelaunch checkout, booster guidance, and Saturn V lunar trajectory injection while issuing course-correction signals 25 times per second during launch.
The Saturn digital computer, developed by IBM’s Electronics Systems Center in Owego, NY, was integral to the launch vehicle guidance system. It managed prelaunch checkout, booster guidance, and Saturn V lunar trajectory injection while issuing course-correction signals 25 times per second during launch.

The System/360 not only transformed the world of computing through compatibility and scalability but also left an indelible mark on modern technology. Its influence can still be felt today in various aspects of the computing industry.

Paving the Way for Future Mainframe Advancements

IBM’s commitment to compatibility set a precedent for future mainframe advancements. The company’s subsequent mainframe generations, such as the System/370, System/390, and the current System z, have all been built upon the foundations laid by the System/360. As a result, IBM has maintained its position as a leader in mainframe technology, offering innovative solutions that continue to support businesses worldwide.

Inspiring Technological Innovations

The 1965 Gemini III mission marked the debut of a guidance computer aboard a spacecraft, providing flight information to command pilot Virgil E. Grissom. This pivotal step in the US Moon-landing program showcased the reliability of the 59-pound (27-kg) computer, produced at IBM's Space Guidance Center.
The 1965 Gemini III mission marked the debut of a guidance computer aboard a spacecraft, providing flight information to command pilot Virgil E. Grissom. This pivotal step in the US Moon-landing program showcased the reliability of the 59-pound (27-kg) computer produced at IBM’s Space Guidance Center.

The success of the System/360 inspired other companies to develop compatible technologies, fostering competition and driving innovation. This led to the creation of various devices and peripherals that could easily integrate with existing systems, improving productivity and efficiency in numerous industries.

A Catalyst for Software Development

The System/360 played a significant role in the development of modern software. By creating an environment in which software could be written once and run on multiple systems, IBM encouraged software developers to focus on creating versatile, adaptable programs. This forward-thinking approach laid the groundwork for the software industry as we know it today, with countless applications designed for compatibility and scalability.

A Lasting Impact on Space Exploration

In NASA's Houston Mission Control Center on July 20, 1969, an Eidophor device displayed a televised image of Neil Armstrong and Buzz Aldrin on the moon. (Photo: NASA)
In NASA’s Houston Mission Control Center on July 20, 1969, an Eidophor device displayed a televised image of Neil Armstrong and Buzz Aldrin on the moon. (Photo: NASA)

IBM’s System/360 played a pivotal role in NASA’s Apollo missions, showcasing the power of mainframe technology to process vast amounts of data and provide mission-critical support. This achievement not only demonstrated the potential of mainframes in space exploration but also paved the way for future collaborations between technology companies and space agencies. Today, advanced computing continues to play a vital role in space exploration, research, and mission planning.

Conclusion

IBM’s System/360 revolutionized the computing industry and left an enduring legacy that continues to shape the world of technology. By introducing compatibility and scalability across its product line, IBM set new standards that fostered innovation, competition, and growth in the computing landscape. From modern mainframe technology to software development and space exploration, the impact of the System/360 can still be felt today, more than half a century after its debut.

Frequently Asked Questions

Q: What computer was used in Apollo 11?

A: The Apollo 11 mission utilized two main computers: the onboard Apollo Guidance Computer (AGC) and the IBM System/360 mainframe on the ground. The AGC provided real-time flight guidance and navigation, while the IBM System/360 processed and translated vast amounts of mission data.

Q: Which IBM computer helped man land on the moon?

A: The IBM System/360 mainframe played a crucial role in the Apollo missions, including Apollo 11. This powerful computer processed, translated, and relayed mission data to flight controllers, aiding in the success of the first manned lunar landing.

Q: Were IBM computers used at NASA?

A: Yes, IBM computers were extensively used at NASA during the Apollo missions. The IBM System/360 mainframe was particularly important for processing and managing the enormous amounts of data generated during these missions.

Q: How big was the computer on Apollo 11?

A: The Apollo Guidance Computer (AGC) onboard Apollo 11 was relatively compact for its time, weighing approximately 70 pounds (32 kg) and measuring 24 x 12.5 x 6 inches (61 x 32 x 15 cm).

Q: What technology was lost on Apollo 11?

A: No significant technology was lost on the Apollo 11 mission. The mission was a success, and the astronauts safely returned to Earth with valuable scientific data and lunar samples.

Q: How many times did the Apollo 11 computer crash?

A: The Apollo Guidance Computer (AGC) experienced several alarms during the lunar descent, which are often referred to as “crashes.” These alarms were caused by an unexpected workload, but the AGC continued to function, and the mission proceeded as planned.

To dive deeper into the technology behind the Apollo 11 mission, check out our article on the Apollo S-band transponder, which highlights another key component that contributed to the mission’s success.

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