6 Barracuda ES.2 Serial ATA Product Ma nual, Rev. ATable 2: Drive specifications summary for 500 GB and 250 GB models
Drive specification ST3500320NS ST3250310NS
Formatted Gbytes (512 bytes/sector)* 500 250
Guaranteed sectors 976,773,168 488,397,168
Heads 4 2
Discs 2 1
Bytes per sector 512
Default sectors per track 63
Default read/write heads 16
Default cylinders 16,383
Recording density, KBPI (kbits/in max) 1,090
Track density, KTPI (ktracks/in avg.) 150
Areal density, (Gbits/in2 avg) 164
Spindle speed (RPM) 7,200
Internal data transfer rate (Mbits/sec max) 1287
Sustained data transfer rate OD (Mbytes/sec max) 105
I/O data-transfer rate (Mbytes/sec max) 300
ATA data-transfer modes supported PIO modes 0–4
Multiword DMA modes 0–2
Ultra DMA modes 0–6
Cache buffer 32 Mbytes
Height (mm max) 26.1 mm (1.028 inches)
Width (mm max) 101.6 mm (4.000 inches) +/- 0.010 inches
Length (mm max) 146.99 mm (5.787 inches)
Weight (max) 530 grams (1.168 lbs) 495 grams (1.091 lbs)
Average latency 4.16 msec
Power-on to ready (sec max) 20 sec
Standby to ready (sec max) 8 sec
Track-to-track seek time (msec typical) 0.8 read; 1.0 write
Average seek, read (msec typical) 8.5
Average seek, write (msec typical) 9.5
Startup current (typical) 12V (peak) 2.8 amps
Voltage tolerance (including noise) 5V + 10% / -7.5%
12V + 10% / -7.5%
Ambient temperature 5° to 55°C (operating)
–40° to 70°C (nonoperating)
Temperature gradient (°C per hour max) 20°C (operating)
30°C (nonoperating)
Relative humidity 5% to 95% (operating)
5% to 95% (nonoperating)
Relative humidity gradient 30% per hour max
Wet bulb temperature (°C max) 37.7 (operating)
40.0 (nonoperating)
Altitude, operating –60.96 m to 3,048 m
(–200 ft. to 10,000+ ft.)
Altitude, nonoperating
(below mean sea level, max)
–60.96 m to 12,192 m
(–200 ft. to 40,000+ ft.)
Operational Shock (max at 2 msec) 70 Gs
Non-Operational Shock (max at 2 msec) 300 Gs