Compaq ProLiant 1000 DDS-3 Enhancing DAT Reliability, Capacity, and Performanc - Page 4

ECG036/1297 7(&+12/2*< %5,() (cont'd) ... The drum in a DAT drive incorporates two read and two write heads, which are diametrically opposite one another (Figure 2). Read head Write head Write head Read head Figure 2: Top view of drum and diametrically opposite read and write heads. Because the write heads in a DAT drive are set at diametrically opposite angles, they record data on adjacent tracks at angles that vary by +20° and -20° (Figure 3). Recording data in diagonal stripes greatly minimizes magnetic crosstalk. Magnetic crosstalk is the interaction between signals from different tracks. Tracks Tape Direction Figure 3: Adjacent tracks are recorded at opposite angles, minimizing magnetic crosstalk. Compaq DAT Drive Product Line From the DDS format specification, Compaq developed a series of DAT drives using DDS technology, the first of which was the 2/4 GB DAT Drive (DDS-1), followed by the 4/8 GB DAT Drive (DDS-2). With the advent of DDS-3 technology, Compaq developed the 12/24 GB DAT Drive, which has a capacity of 12 GB native (uncompressed) and 24 GB compressed.