I don't have an answer for you and worse yet I have a question that maybe Jack or someone with a better understanding of computers could answer.
From a CNET review "one thing the Dell Dimension E310 does provide is advanced data security, namely Dell's DataSafe hardware-and-software-based data-protection solution. In a nutshell, DataSafe is a dual-drive RAID 1 array with a software component that automates backups. Our review unit came with dual 80GB hard drives, but only one of them was available to us for storage. The other remained invisible, taking regular snapshots of the visible drive." If Thirdbird upgrades drives and wishes to use the second drive as a recording destination will some software tweaks be required?

Mine came with two 160s already, and I never had any problem with one being invisible.