Submission + - Bringing modern USB xHCI support to Windows 98/2000 (yeokhengmeng.com)
Sometime in the mid 2010s, Intel broke compatibility with the previous USB host standards by mandating USB 3.0 xHCI and no longer supporting older USB standards in their modern chipsets.
This meant that older operating systems like Win 98 lost all USB functionality even if they could be installed on modern machines.
The vintage OS will work, but you cannot connect anything to it. Even USB 1 and 2 ports and devices will not work. BIOS support can mitigate this somewhat but only basic devices like keyboard, mouse and storage will work but you cannot hotplug them. All other devices will not work.
With AI's help, I decided to address this gap to create an xHCI miniport driver so Windows 98 will work better on modern machine.