MICROSOFT OPEN-SOURCES EARLIEST DOS CODE EVER FOUND

INDUSTRY DESK■ 1 MIN READ

SAT, MAY 23, 2026

■ AI-SUMMARIZED FROM 3 SOURCES ▸ TIMELINE

Microsoft has released the source code for 86-DOS, predating the company's 1981 acquisition of the operating system. The release marks a significant moment for computing history.

The open-sourced code dates back to before Microsoft purchased DOS, providing developers and historians with a rare glimpse into the early foundations of personal computing. The move underscores Microsoft's recent shift toward transparency around legacy technology. In other Microsoft updates, the company has fixed a bug causing Windows security warnings to display incorrectly when opening Remote Desktop (.rdp) files. Meanwhile, Microsoft is testing a modernized Windows 11 Run menu for Insiders in the Experimental Channel. The redesign introduces dark mode support and improved performance. The company removed the "Browse" button after discovering minimal user adoption, replacing it with a new "~\" command for direct home directory access. The refresh aims to bring the decades-old Run utility into line with modern Windows design standards.

■ SOURCES

► Ars Technica ► Bleeping Computer ► The Verge

■ SUMMARY WRITTEN BY AI FROM THE LINKS ABOVE

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MICROSOFT OPEN-SOURCES EARLIEST DOS CODE EVER FOUND

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