UDO comes in both internal and external drive guises. Selection of the internal/external drive arrangement is often idiosyncratic. The Jaz drive uses a SCSI interface, with both internal and external drive models. The HiFD was re-released in November 1999, using a USB connection for the external drive. These vulnerabilities allow an attacker to boot from an external drive and compromise the firmware. The optical drive can then be repurposed as an external drive. Peter places a backup CD into the external drive while the others set up. They disconnect the existing hard drive and connect an external drive using an industrial endoscope. There were several external drive systems available for the H89/Z-89. However, the external drive may be removed (along with content) without losing settings. The external drive plugs into the TiVo box using an eSATA interface.