Advertisements The problem is not the size of the unit in this case (since it can be configured as RAID 0+1 or Raid 5 with hot spare, both of which would be 1TB) but the fact that it uses a RAID controller card and software drivers. You can only use true hardware RAID which can connect to any eSATA port (not just their proprietary eSATA RAID controller) and appear to the host as a single drive without any drivers required. Rule of thumb: If it includes a proprietary controller card or a disk with drivers it is incompatible. In an era of quiet and affordable 1TB drives there is little purpose for a RAID unit on the TiVo unless you have some perceived need for data redundancy and don't mind the noise and heat. A year ago there were no 1TB drives and no quiet 750GB ones so a RAID of smaller drives was the only solution.