5.0Performance characteristics

This section provides detailed information concerning performance-related characteristics and features of Con- stellation drives.

5.1Internal drive characteristics

 

ST9500430SS, ST9500431SS & ST9500432SS

Drive capacity

500

Gbytes (formatted, rounded off value)

Read/write data heads

6

 

Bytes per track

890,823

Bytes (average, rounded off values)

Bytes per surface

83,370

Mbytes (unformatted, rounded off value)

Tracks per surface (total)

123,148

Tracks (user accessible)

Tracks per inch

200,000

TPI (average)

Peak bits per inch

1,410,000

BPI

Areal density

283

Gbit/in2

Internal data rate

75 - 142

Mbytes/sec (variable with zone)

Disc rotation speed

7,200

rpm

Avg rotational latency

4.16

msec

5.2Seek performance characteristics

See Section 12.4.1, "SAS physical interface" on page 56 and the SAS Interface Manual (part number 100293071) for additional timing details.

5.2.1Access time

 

 

Including controller overhead1, 2

Not including controller overhead1, 2

 

 

(msec)

 

(msec)

 

 

 

Read

Write

Read

Write

Average

Typical3,4

8.2

8.6

8.0

8.4

Single track

Typical3,4

0.5

0.7

0.5

0.7

Full stroke

Typical3,4

17.55

18.02

17.35

17.82

1.Execution time measured from receipt of the Command to the Response.

2.Assumes no errors and no sector has been relocated.

3.Typical access times are measured under nominal conditions of temperature, voltage, and horizontal orientation as measured on a representative sample of drives.

4.Access time = controller overhead + average seek time and applies to all data transfer commands. Access to data = access time + latency time.

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Constellation SAS Product Manual, Rev. E

Page 18
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Seagate ST9500430SS manual Performance characteristics, Internal drive characteristics, Seek performance characteristics