TRS IDE occupies 16 addresses 0x40-0x47, and a mirror at 0x48-0x4F (A3 is not connected).
In this address space the IDE registers are mapped 1 to 1. The upper data register byte
is unconnected.

Occupied I/O addresses:
0x40	IDE data register
0x41	IDE error/feature register
0x42	IDE sector count register
0x43	IDE sector number register
0x44	IDE cylinder low register
0x45	IDE cylinder high register
0x46	IDE drive/head register
0x48	IDE command/status register

GIDE and

The G-IDE occupies 12 addresses. The base address is configurable in 16 steps, so can be
mapped in the whole I/O-space (address lines A4-A7). The 16 bit data register can be 
addressed with two 8-bit accesses (Z80 instructions INI and OTIR). The IDE registers are
mapped from BASE+0x8 to BASE+0xF. The extra IDE addresses (alternate status/digital 
output register and IDE drive address register are mapped to 0x6 and 0x7. At 0x5 is the
Real Time clock. 0x4 is decoded for expansion

Occupied I/O addresses:
0x?4	reserved for IDE expansion board
0x?5	RTC access
0x?6	IDE alternate status / digital output register
0x?7	IDE drive address register
0x?8	IDE data register
0x?9	IDE error/feature register
0x?A	IDE sector count register
0x?B	IDE sector number register
0x?C	IDE cylinder low register
0x?D	IDE cylinder high register
0x?E	IDE drive/head register
0x?F	IDE command/status register

(? is configurable from 0 to F)

A driver written for the TRS-IDE, using only half of each 512-byte sector can be adapted
for the GIDE, by writing a dummy byte during the second half of the block transfer. The 
disk could even be compatible between the two drivers! 

Using the full GIDE potential is possible only by rewriting a larger part of the driver.
Reading is no problem, but writing will become slower ar the other half of the sector should
be read first, the two halves combined and then written to disk. Buffer space is 768 bytes.

As reference, the register set of the WD1002-HD0:

Addres Read              Write
0x00   Sector Buffer   / Sector Buffer
0x01   Error Register  / Write precompensation
0x02   Sector Count    / Sector Count
0x03   Sector Number   / Sector Number
0x04   Cylinder Low    / Cylinder Low
0x05   Cylinder High   / Cylinder High
0x06   Size/Drive/Head / Size/Drive/Head
0x07   Status Register / Command Register