I have a PCI device driver that maps a range of memory in StartDevice,
using MmMapIoSpace. In StopDevice, it calls MmUnmapIoSpace with the
pointer returned by MmMapIoSpace. On Win2K and XP this works fine. On
Win98, it throws a page fault and crashes the host. Apparently no one
ever uninstalled one of these devices on 98. 
(in 98, StopDevice
doesn’t get called on a shutdown or reboot, according to the debug
console) Is this a known issue with 98? I STFW and came up empty. Clues
appreciated.