Microsoft at 50

Microsoft is celebrating its 50th anniversary in 2025. The company was started in 1975.

To mark the occasion, founder Bill Gates has released the original code that launched the entire technology company — the Altair BASIC interpreter. According to Gates, it was “the coolest code I’ve ever written.”

The source code is now available at the celebration page at https://www.gatesnotes.com/microsoft-original-source-code

In 1975, a young Harvard student named Gates and his friend Paul Allen were intrigued by an article in Popular Electronics magazine that introduced a new microcomputer called the Altair 8800.

They saw that personal computers could be a reality — if only someone would write software for them. They contacted the Altair’s manufacturer, Micro Instrumentation and Telemetry Systems (MITS). Gates and Allen thought promised to deliver a ready-to-use version of the popular BASIC programming language. There was just one problem — they had never even seen an Altair computer in person, let alone wrote any code for one. Gates and Allen worked for two months, almost without sleep, developing the program on Harvard’s PDP-10 computer, simulating the operation of the Altair’s 8080 processor. The result was a 4-kilobyte interpreter.

This Altair BASIC was Microsoft’s first product – and the beginning of the software giant’s journey.

Sources:
https://www.vintagecomputer.net/altair-poptronics.cfm
https://www.gatesnotes.com/microsoft-original-source-code
https://hackaday.com/2025/04/03/a-very-trippy-look-at-microsofts-beginnings/
https://etn.fi/index.php/13-news/17361-microsoft-laehti-liikkeelle-50-vuotta-sitten-basic-tulkista