Microsoft turns 50 this April 4. To mark the occasion, its founder Bill Gates reflects on the company’s beginnings by publicly sharing the source code that started it all: the very first software ever developed by the company.
It all began in January 1975 when Bill Gates, then a 19-year-old Harvard student, and his childhood friend Paul Allen came across the cover of Popular Electronics magazine. That issue introduced the Altair 8800, a revolutionary computer at the time, developed by MITS (Micro Instrumentation and Telemetry Systems).
Gates and Allen immediately sensed that the era of personal computing was beginning. They decided to seize the opportunity and promised MITS a piece of software that could run on the new machine.
At that point, Gates and Allen had no existing code to show the company. So they threw themselves into a furious coding sprint, working day and night for nearly two months.
They were joined by a third developer, Monte Davidoff, who was responsible for the math functions in the software.
Without even having access to an actual Altair, they built a version of the BASIC programming language—originally created at Dartmouth in 1964—tailored specifically for the Altair computer.
Paul Allen developed a simulator for the Intel 8080 processor used by the Altair, allowing Bill Gates and Monte Davidoff to code the BASIC interpreter on it.
Gates printed his work using a teletype machine—a reminder of a time when every line of code was literally printed on paper.
After this marathon session, the software was ready and presented to MITS, who immediately licensed it. “Altair BASIC” became the first product of a new company named Micro-Soft—the hyphen would be dropped a few years later.
“This is the coolest code I’ve ever written,” says Gates, now 69, in a special nostalgic post published on his personal blog, Gates Notes.
To mark this half-century milestone, Microsoft’s founder decided to release the original source code of that first software, available for anyone to download (as a PDF file).
This symbolic gesture serves as a reminder of how far the Redmond-based company has come—from that first chunk of code to today’s flagship products like Windows, the Office suite, Windows Phone, and even the Xbox.
“It’s pretty wild to think that one piece of code could kick off fifty years of innovation,” Gates concludes.
Half a century later, Microsoft is now worth nearly $2.8 trillion on the stock market. That’s quite the return on a few thousand lines of paper code.
