Western Digital Caviar 120GB 7.2K EIDE Hard Drive WD1200BB

Capacity: 120GB
Spindle Speed: 7,200RPM
Interface Type: IDE / ATA (3.5″)
Disk Size: 3.5″x1.0″ (LFF Hard Drive)
Sustained Throughput (MBps): 
Average Seek Time (read/write ms): 8.9 / 10.9
Electrical Interface Speed: EIDE / Ultra ATA/100 – 100MBps
On-Board Cache: 2MB

Key Features

• RAID-specific time-limited error recovery improves compatibility with RAID adapters, and prevents drive fallout caused by the extended hard drive error-recovery processes common to desktop hard drives.
• 1 million hours MTBF meets enterprise-class reliability standards.
• Backed by an industry-leading five-year warranty.
• 8 MB cache provides a higher percentage of cache hits and significantly faster time to data than industry-standard 2 MB versions

Model : WD1200BBhysical Specifications
Formatted Capacity	120,034 MB
Interface	40-pin EIDE
Actuator Type	Rotary Voice Coil
Number of Disks	2
Data Surfaces	4
Number of Heads	4
Bytes Per SECTOR	512
User SECTORS Per Drive	234,441,648
Servo Type	Embedded
Recording Method EPR4	Rate 16/17 PRML
ECC	Reed Solomon
Head Park 2	Automatic

PRML – Partial Response Maximum Likelihood
EIDE – Enhanced Integrated Drive Electronics

² Turning the system power off causes the WD Caviar® to perform an automatic head park operation.

Performance Specifications
Average Seek 1 – Read – Write	8.9 ms average 10.9 ms average
Track-to-Track Seek	2.0 ms average
Full Stroke Seek	21 ms average
INDEX Pulse Period	8.3 ms (nominal)
Average Latency	4.2 ms (nominal)
Rotational Speed	7200 RPM (nominal)
Data Transfer Rate (maximum)	100 MB/s (Mode 5 Ultra ATA) 66.6 MB/s (Mode 4 Ultra ATA) 33.3 MB/s (Mode 2 Ultra ATA) 16.6 MB/s (Mode 4 PIO) 16.6 MB/s (Mode 2 multi-word DMA)
Interleave	1:1
Buffer Size	2 MB
Error Rate – Unrecoverable	<1 in 1014 bits read
Spindle Start Time – From Power-on to Drive Ready 2 – From Power-on to Rotational Speed 3	7.0 s average  5.0 s average
Spindle Stop Time	6.5 s average
Contact Start/Stop Cycles (CSS)	50,000 minimum

¹ When measuring seek times, the average latency must be subtracted from read, write, or explicit seek commands.
² Defined as the time from power-on to the setting of the Drive Ready and Seek Complete including calibration.
³ Defined as the time from power-on to when the full spindle rotational speed is reached.