16-bit IDE-HD-driver wiring details:
How to wire you`ll find in the verdraht.txt. It should be mentioned that the 74hc04-iverter should be build into the par. Interface as near as possible to the 82c55-chip to avoid random peakes and noise.
Try to limit the cable-length outside the par. interface down to 10cm.
Its not so easy to pin out the additional 7 datalines from pin 18 to 25.
I for myself used a small drillingmachine and a rotating cutting-device to cut the pcb-board, means to free the pins 18 to 25 for free wiring.

Another nice and stable solution has been suggested by Dr. Jochen A.Borchert. He built up a rather small pcb with a 82c55 at the Portfolios system-bus just for the purpose to control the external HD.
Contact "dr.jochen.a.borchert@t-online.de" for details and prices. 

Its planed to build another ide-hd-driver with 8-bit access only.
Thus will be slower in performance and will access half of a disks- capacity only, but without any necessity to change the par. interface or build a new interface.   

Stefan in 2.99