To commemorate Microsoft’s 50th anniversary, Bill Gates has released the original source code for Altair BASIC, the company’s very first product. Developed in 1975 by Gates and his late partner Paul Allen, Altair BASIC was a revolutionary interpreter that allowed users to write and execute programs on the MITS Altair 8800, one of the earliest personal computers. Gates has referred to this code as one of the most remarkable pieces he ever worked on, reflecting its historical and personal significance in launching Microsoft.
The inspiration for Altair BASIC came from a 1975 issue of Popular Electronics, which featured the Altair 8800 microcomputer. Gates and Allen, recognizing a major opportunity, contacted MITS with the bold claim that they had created a working BASIC interpreter for the Altair. Although they had not yet written it, their confidence drove them to complete the code in just a few weeks. Working without direct access to the hardware, they simulated the Intel 8080 processor using a Harvard mainframe, showcasing their determination and technical ingenuity.
After completing the software, the duo presented their creation to MITS, which agreed to license and distribute it. This collaboration marked the formal beginning of Microsoft, initially known as Micro-Soft, and positioned Altair BASIC as the foundational product of what would become one of the world’s most influential tech companies. The success of Altair BASIC not only validated Gates and Allen’s vision but also ignited the evolution of commercial software development.
In reflecting on the journey, Gates expressed gratitude to those who carried the Microsoft legacy forward, including successors like Steve Ballmer and Satya Nadella. He emphasized that the Altair BASIC source code represented the spark that led to an entire ecosystem of innovations, ranging from productivity software like Microsoft Office to breakthroughs in cloud computing and artificial intelligence. The release of this code offers a symbolic look back at how far the company has come in half a century.
The full 157-page source code is now publicly accessible on Gates’s blog, offering historians, developers, and tech enthusiasts a rare glimpse into the origins of modern computing. This archival release serves as both an educational resource and a celebration of Microsoft’s roots, illustrating the passion and pioneering spirit that fueled its creation in a rapidly evolving digital world.
