As Microsoft turns 50, Bill Gates is taking tech enthusiasts on a nostalgic trip by sharing the very foundation of the company—the original source code that launched Microsoft into history.

In a heartfelt post on his Gates Notes blog, the billionaire co-founder reflected on the journey, calling the milestone "bittersweet." He also made a special announcement: the source code for Microsoft’s first product is now available for anyone to download.

From Harvard’s Lab to a Tech Revolution

Gates reminisced about the early days when he and Paul Allen worked tirelessly in Harvard’s computer lab, writing code on a PDP-10 minicomputer. That code would later become Microsoft’s first official product.

“It’s hard to believe 50 years have passed,” Gates wrote. “We owe this success to the brilliant minds at Microsoft—from Steve Ballmer to Satya Nadella—and every employee who helped shape our legacy.”

The Birth of Microsoft (or, Originally, Micro-Soft)

The story of Microsoft began with a magazine. In January 1975, Popular Electronics featured the Altair 8800, one of the first personal computers, built by a small company called MITS.

Seeing an opportunity, 19-year-old Gates and Allen contacted MITS, claiming they had developed a version of BASIC (a programming language) for the Altair’s processor. There was just one catch—they hadn’t actually written it yet.

With no time to waste, Gates, Allen, and their team worked around the clock for two months, turning their bold claim into reality. The result? The software that would launch Microsoft and change computing forever.

Now, half a century later, Gates is letting the world see the code that started it all—a rare glimpse into the origins of one of tech’s most influential companies.

Bill Gates Releases Microsoft’s Original Source Code to Celebrate 50th Anniversary