50 years later, Bill Gates returns to the BASIC code that became Microsoft

On April 4, 1975, two college dropouts—Bill Gates and Paul Allen—set out to write software for a microcomputer that didn’t even exist yet. Today, as Microsoft turns 50, Gates is once again looking at that code, but this time through the lens of a legacy that’s reshaped the world.

In a commemorative blog post, Gates shared for the first time the original source code of Altair BASIC—the software he and Allen wrote in their early twenties—and reflected on how it became the first product “Microsoft” ever sold.

It’s amazing to think about how…