It was still possible to use "real mode" (16-bit DOS) device drivers with Win95. [1] I believe there was a 32-bit kernel running on top of this 16-bit foundatio

It was still possible to use "real mode" (16-bit DOS) device drivers with Win95. [1] I believe there was a 32-bit kernel running on top of this 16-bit foundation, but it was definitely a hybrid arrangement. User space processes definitely ran in 32-bit "protected mode", and 16-bit legacy processes ran in their own protected address space when run from inside Win95 - with the 32-bit OS kernel taking the place of what would normally have been the interplay of BIOS and DOS, handling the interrupts routinely generated by 16-bit DOS software for making what we would now call syscalls. I believe much of this was already in place with Windows 3.1(1)'s 386 enhanced mode and Win32s, although from memory Windows 95 moved far more device drivers into the 32-bit kernel. Presumably this was enabled by not having to be able to end the windowing session and quit back to DOS without rebooting. [1] I seem to remember CD-ROM drive controller drivers being particularly common culprits in this regard, with virtual mode device drivers often being unavailable, so you had to use real mode drivers in config.sys even on Win9x. Yes, back in the day of single-, double-, and quad-speed CD-ROM drives, you typically had an ISA card with a custom controller that then connected to the CD-ROM drive via an "I can't believe it's not IDE" ribbon cable. Only later did we get ATAPI and hard drives and optical drives could use the same controller and bus. (Sound cards often had an on-board CD-ROM drive controller and ribbon cable connector around that time.)