It is possible to use SET FEATURES to put the X-MASS into 16-bit mode, but then you would only read 8 of the 16-bits of data that ATA devices often use, and you would only be able to use half the capacity of the device and you would not be able to read devices formatted on the PC for example.
In default configuration the X-MASS operates the same as the Symbiface 2 SYMBiFACE II IDE and has the same functionality.
The I/O ports operate in a "pass-through" like mode where the registers directly reflect those of the connected ATA device.
Like the Symbiface 2SYMBiFACE II, the device should be selected with port FD0E first, then the other I/O ports can be used to program the selected device.
The I/O port is decoded fully: