On 12/8/2005 at 9:49 PM Allison wrote: However, the 8089 IOP was a piece of cruft and one big pain to debug. Expensive, short-sighted and brain-dead, but it did have a flat 20-bit addressing space. The 186 with integrated periopherals and 20 bit DMA pretty much put the kebosh on it. Cheers, Chuck