[danachow]

You are not remembering correctly. No flavor of Windows NT (this includes 2000 and XP) gave direct hardware access out of the box.

There were a couple of undocumented but well known NT kernel functions to manipulate the task IO permission level (eg Ke386SetIoAccessMap) and there was a commonly used hack/gaping security hole to manipulate these with a 3rd party driver that was built to do nothing except that (probably the most commonly shared one went by the name of GIVEIO.SYS - first presented in Dr Dobbs Journal in the 90s). This would work similarly on Vista and 7 as it would on the older OSes.

Win2k didn’t so much as force you into flat mode as it was a completely different kernel architecture from Windows 98/95 - the “security benefits” include the myriad other ways that NT is an actual multiuser OS vs 98/95 being a glorified DOS extender. The Windows 11 kernel is an NT descendant through 2000/XP and the preceding NT 4/3 releases preceding those.

* The above mentioned driver has even been updated by internets for 64-but Windows https://www-user.tu-chemnitz.de/~heha/hsn/giveio64.zip/readm...