See:
http://www.wiebetech.com/ATA6firewire.htm

“Utilizing High Capacity ATA-6 (>137GB) Drives in FireWire Enclosures”

by James Wiebe, CEO
WiebeTech LLC
October 21, 2002
www.wiebetech.com
© 2002 WiebeTech LLC. All rights reserved.

The OXFW911 was designed to support ATA-5 (but not ATA-6) devices, which, by definition, are less than 137GB in capacity.

Western Digital started shipping drives with capacities of 180 and 200GB, and it became obvious that OXFW911's didn't work (especially with the 200GB version). These new drives were true ATA-6 devices, and the OXFW911 did not 'speak' true ATA-6 protocol.

Most OXFW911 designs currently shipping are not capable of providing ATA-6 support (unless the vendor specifically provides and supports an upgrade program).

The OXFW911, when modified with ATA-6 support, remains the preferred solution for FireWire drives.