Comment stupid, stupid idea (Score 2) 27
The programming guide for the Amiga cautioned not to use the upper 8 bits of an address for ANYTHING, because, although the MC68000 only bonded out the lower address bits, it was still a 32-bit processor and future versions might bring out all the address lines. The never-to-be-forgiven (for this among other things) clowns at Microsoft ignored the directive and used to upper address bits in their BASIC, which promptly broke everything when the 68020 (all lines bonded out) came out.
Unless someone shows some intelligence and reverts that disaster-in-the-making, we will be stuck with incompatibilities and restrictions for however long Linux/X86 lasts.