If Windows 3.11 required a 32-bit processor, why was it called a 16-bit operating system?
https://devblogs.microsoft.com/oldnewthing/?p=14013

> Recall that Enhanced mode Windows allowed you to run multiple
> MS-DOS prompts that were pre-emptively multi-tasked.

拡張モードならMS-DOSプロンプトはプリエンプティブマルチタスクで動くはずだが?