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Seagate Enterprise NAS HDD Product Manual, Rev. B 13
www.seagate.com Drive Specifications
2.10 Acoustics
Drive acoustics are measured as overall A-weighted acoustic sound power levels (no pure tones). All measurements are consistent
with ISO document 7779. Sound power measurements are taken under essentially free-field conditions over a reflecting plane. For all
tests, the drive is oriented with the cover facing upward.
*During periods of drive idle, some offline activity may occur according to the S.M.A.R.T. specification, which may increase acoustic and power to operational levels.
2.10.1 Test for Prominent Discrete Tones (PDTs)
Seagate follows the ECMA-74 standards for measurement and identification of PDTs. An exception to this process is the use of the
absolute threshold of hearing. Seagate uses this threshold curve (originated in ISO 389-7) to discern tone audibility and to compensate
for the inaudible components of sound prior to computation of tone ratios according to Annex D of the ECMA-74 standards.
2.11 Electromagnetic immunity
When properly installed in a representative host system, the drive operates without errors or degradation in performance when
subjected to the radio frequency (RF) environments defined in
Table 6.
2.12 MTBF and Warranty
The product will achieve a Mean Time Between Failure Rate (MTBF) of 1,000,000 hours when operated in an environment of ambient
air temperatures of 25°C. Operation at temperatures outside the specifications shown in Section 2.9, "Environmental specifications."
may increase the product MTBF. MTBF is a population statistic that is not relevant to individual units.
MTBF specifications are based on the following assumptions for NAS environments:
• 8760 power-on hours per year
• 10,000 average motor start/stop cycles per year
• Operations at nominal voltages
• Temperatures outside the specifications in page 11 may reduce the product reliability.
Operation at excessive I/O duty cycle may degrade product reliability. The NAS environment of power-on hours, temperature, and I/O
duty cycle affect the product MTBF. The MTBF will be degraded if used in an enterprise application.
Note
For seek mode tests, the drive is placed in seek mode only.
The number of seeks per second is defined by the following equation:
(Number of seeks per second = 0.4 / (average latency + average access time
Table 5 Fluid Dynamic Bearing (FDB) motor acoustics
Idle* Seek
2.5 bels (typical)
2.6 bels (max)
2.6 bels (typical)
2.7 bels (max)
Table 6 Radio frequency environments
Test Description
Performance
level
Reference
standard
Electrostatic discharge Contact, HCP, VCP: ± 4 kV; Air: ± 8 kV B EN61000-4-2: 95
Radiated RF immunity 80MHz to 1,000MHz, 3 V/m,
80% AM with 1kHz sine
900MHz, 3 V/m, 50% pulse modulation @
200Hz
A EN61000-4-3: 96
ENV50204: 95
Electrical fast transient ± 1 kV on AC mains, ± 0.5 kV on external I/O B EN61000-4-4: 95
Surge immunity ± 1 kV differential, ± 2 kV common,
AC mains
B EN61000-4-5: 95
Conducted RF immunity 150kHz to 80MHz, 3 Vrms, 80% AM with 1kHz
sine
A EN61000-4-6: 97
Voltage dips, interrupts 0% open, 5 seconds
0% short, 5 seconds
40%, 0.10 seconds
70%, 0.01 seconds
C
C
C
B
EN61000-4-11: 94