Any operating system that can memory map linear regions in really high memory should work. This should include Linux, FreeBSD, SVR4, and more.
If you have NetBSD, you will need to install the aperture driver.
Extract the file apNetBSD.shar
(in xc/programs/Xserver/hw/xfree86/etc/apNetBSD.shar) and read
the README contained therein.