As Microsoft celebrates its 50th anniversary this week, founder Bill Gates has marked the occasion by sharing a piece of computing history with the world. The billionaire philanthropist has released the original source code for the BASIC interpreter that he and Paul Allen wrote in 1975, the programming language that helped launch the personal computing revolution and laid the foundation for what would become one of the world's most valuable technology companies.
The Birth of Microsoft
In a reflective blog post commemorating Microsoft's golden anniversary, Gates recounts how he and his high school friend Paul Allen were inspired by a January 1975 article in Popular Electronics magazine featuring the Altair 8800 minicomputer. Despite being a freshman at Harvard, Gates made a bold decision that would change the course of computing history. He and Allen contacted Ed Roberts, CEO of Micro Instrumentation and Telemetry Systems (MITS), claiming they had developed software for the Altair—even though they hadn't yet written a single line of code.
Historical Timeline:
- 1964: BASIC programming language developed at Dartmouth College
- January 1975: Popular Electronics features Altair 8800 article
- Early 1975: Gates and Allen develop BASIC interpreter for Altair 8800
- April 1975: Microsoft officially founded
- 2025: Microsoft celebrates 50th anniversary
A Race Against Time
What followed was an intense two-month coding marathon. Gates and Allen worked tirelessly to adapt the BASIC programming language, originally developed at Dartmouth College in 1964, to work on the Altair 8800. The challenge was particularly daunting because they didn't even have a prototype of the machine they were developing for. Instead, they used a PDP-10 computer to emulate the Intel 8080 processor that would power the Altair, creating both the emulator and the BASIC interpreter simultaneously.
Key Technical Achievement: Gates and Allen created two critical components:
- An emulator for the Intel 8080 processor on a PDP-10 computer
- A BASIC interpreter that could run on the Altair 8800's limited hardware
The Code That Changed Everything
That code remains the coolest I've ever written, Gates reflected in his blog post, which now includes an option for anyone to download the original program as a 157-page PDF. This release provides a rare glimpse into the early days of personal computing and showcases the technical prowess of the young programmers who would go on to revolutionize the industry. The meticulously documented code reveals careful attention to both functionality and maintainability—impressive qualities for a rushed project created by programmers in their early twenties.
Why BASIC Mattered
The significance of this early BASIC interpreter cannot be overstated. Before Gates and Allen's creation, programming personal computers required tedious machine code or assembly language programming—processes that were prohibitively complex for most users. BASIC offered an accessible entry point that made personal computing viable for the average person. Its interactive nature allowed users to write programs and see immediate results, creating an engaging experience that helped fuel the PC revolution.
From Humble Beginnings to Tech Giant
The success of this initial software project led to the official founding of Microsoft in April 1975. From those humble beginnings, Microsoft grew into a technology behemoth that would develop the Windows operating system and productivity software like Word, Excel, and PowerPoint that continue to dominate the PC landscape today. The company now boasts a market value of approximately USD 2.8 trillion, cementing its place as one of the most successful enterprises in history.
A Personal Reflection
At 69 years old, Gates has been in a reflective mood this year, having recently published a memoir about his early years and celebrating the 25th anniversary of the Bill & Melinda Gates Foundation. Looking back on the code that started it all, Gates simply stated, Fifty years is a long time. It's crazy that the dream came true.
The Legacy Continues
The release of this historic code provides both a nostalgic look back for computing veterans and an educational opportunity for younger generations to understand the foundations upon which today's technology was built. While BASIC may have fallen out of favor compared to modern programming languages, its impact on making computing accessible cannot be understated. It served as a gateway for countless programmers who would go on to shape the digital world we live in today.
As Microsoft celebrates this milestone anniversary, the company continues to evolve under CEO Satya Nadella, focusing on cloud computing, artificial intelligence, and maintaining its position as one of the world's most influential technology companies—all built upon the foundation laid by two young programmers with a vision of making personal computing a reality.