Thirty years ago, Windows 95 was too big and complicated to install on its own, so Microsoft relied on a smaller version called Windows 3.1 instead. Now, an engineer who worked at Microsoft back then has explained why they chose that approach.
To understand what happened, let’s go back to the setup process of Windows 95 in the 1990s. If you started from MS-DOS, Windows 3.1 was installed first, and a separate program would handle copying files and transferring settings before launching Windows 95. If you started with Windows 3.1, the same app would start automatically.
The question on everyone’s mind is: why not just use a smaller version of Windows 95 from the start? The answer lies in engineering and user experience issues. Developing an extra miniature OS would have added unnecessary work to Microsoft’s already-behind-schedule project.
Additionally, using a smaller version required multiple reboots, which broke the one-reboot principle that users were used to at the time. Engineers also had to consider the disk space needed for installation – two floppy disks compared to one with Windows 3.1.
Chen explains that having an extra step involved less engineering effort and resulted in a smoother user experience. The smaller version of Windows 3.1 was already developed, so there were no significant costs or complications added to the process.
This answer highlights how, even thirty years later, engineers still grapple with issues like disk space, reboots, and workflow.
Source: https://www.theregister.com/2025/09/29/chen_windows_95_install