At the conclusion of his blog post, Bill Gates shared the original source code that holds significant sentimental value for him, as it was foundational to the emergence of Microsoft. The story of Microsoft began in January 1975, when Gates and co-founder Paul Allen came across an article in *Popular Electronics* featuring the Altair 8800, an early home computer created by MITS.
Gates recounts, “When Paul and I saw that cover, we knew two things: the PC revolution was imminent, and we wanted to get in on the ground floor.” This realization prompted them to create software that would enable Altair 8800 users to write their own programs using the straightforward BASIC programming language.
They quickly set out to develop a BASIC interpreter specifically for the Altair 8800. This interpreter was designed to convert BASIC commands into machine code compatible with the Altair 8800.
The challenge was significant; the interpreter had to function within a limited maximum of 4 kilobytes of memory to ensure that users could still run other programs on their machines. Notably, Gates and Allen created Microsoft’s first software in just two months, even though they did not own an Intel 8080 chip, the very one used in the Altair 8800.
To bridge this gap, Allen built a simulator on a Harvard PDP-10 mainframe. Gates focused on the interpreter’s main code, while another programmer, Monte Davidoff, contributed to the math package.
After completing the project, they presented the BASIC interpreter to MITS, which licensed it as Altair BASIC, marking the first official product of their newly formed company, Micro-Soft. Reflecting on this origins story, Gates remarks, “It’s amazing to think how this one piece of code led to half a century of innovation at Microsoft.”
Even decades later, the source code remains a source of nostalgia and pride for him.