If by "buffered interface" you mean a 4-way adapter which offers two IDE channels and the ZIP drive is connected to the second channel, then no. Only the first channel of the interface is recognised by AmigaOS. If you connect the ZIP drive to the first channel (or even without the 4-way adapter) then it will be recognised by AmigaOS 3.9. For the second channel you need IDEfix.
Why don't you like IDEfix ? It is a very nice piece of software.
Bye,
Thomas
