Perpendicular recording is a technology first introduced in the 7200.10 line and is succeeded by the second generation version found in the newer 7200.11 drives. Perpendicular recording aligns the bits vertically on the disk rather than horizontally, effectively squeezing more data in a smaller area. This means that hard drives made in such a way can increase their maximum capacity, as well as deliver increased sustained data throughput. The drive head can read more data in a small physical distance.
Figure: Bit orientations for longitudinal recording (above) and perpendicular recording (below). (via The Tech Report)
| Specifications |
320 GB |
| Model Number |
ST3320620AS |
| Interface |
SATA 3.0Gb/s |
| Cache |
16 MBytes |
| Capacity |
320 GB |
| Guaranteed Sectors |
625,142,448 |
| PHYSICAL |
|
| Height (max) |
26.1 mm (1.028 inches) |
| Width (max) |
101.6 mm (4.010 inches) |
| Length (max) |
146.99 mm (5.787 inches) |
| Weight (typical) |
635 grams (1.40 pounds) |
| PERFORMANCE |
|
| Spindle Speed |
7,200 rpm |
| Average latency |
4.16 msec |
| Random read seek time |
<8.5 msec |
| Random write seek time |
<10.0 msec |
| RELIABILITY |
|
| MTBF |
700,000 hours |
| Annual Failure Rate |
0.34 % |
| POWER |
|
| Maximum start current, DC |
2.80 amps |
