>  JV> page of ports are always on the 8MHz bus, and port 4Fh is
>  JV> always unused, so a stable form of jmp $+2.
>  
> I think it would be highly unwise to rely on this being true forever.
Long time no see, Darryl. :-)    
I seem to recall that 4F was mirrored on the motherboard in some
way and impossible to use in any real fashion..? I don't think
a card on the bus can use anything in that range, and if that
is true it means a motherboard manufacturer would have to be the 
guilty party. 
Here's a clip from the Linux kernel. He uses port 80h, which
shows in a port list as being used for DMA.. Any comments?
/*
 * Thanks to James van Artsdalen for a better timing-fix than
 * the two short jumps: using outb's to a nonexistent port seems
 * to guarantee better timings even on fast machines.
 *
 * On the other hand, I'd like to be sure of a non-existent port:
 * I feel a bit unsafe about using 0x80 (should be safe, though)
 *
 *		Linus
 */
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