Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate

Barracuda 18LP Product Manual, Rev. E 9
4.0 Performance characteristics
4.1 Internal drive characteristics (transparent to user)
ST39175
ST318275
Drive capacity 9.1 18.2 Gbyte (formatted, rounded off values)
Read/write heads 5 10
Bytes/track 186 186 Kbytes (average, rounded off values)
Bytes/surface 2,184 2,184 Mbytes (unformatted, rounded off values)
Tracks/surface (total) 11,721 11,721 Tracks (user accessible)
Tracks/inch 12,580 12,580 TPI
Peak bits/inch 223 223 KBPI
Internal data rate 137-240 137-240 Mbits/sec (variable with zone)
Disc rotational speed 7,200 7,200 r/min ± 0.5%
Average rotational latency 4.17 4.17 msec
Recording code 16/17 16/17 EPR4
4.2 SCSI performance characteristics (visible to user)*
The values given in Section 4.2.1 apply to all models of the Barracuda 18LP family unless otherwise specified.
Refer to Section 9.10 and to the SCSI Interface Product Manual, part number 77738479, for additional timing
details.
4.2.1 Access time [8]
Including controller overhead
(without disconnect) [1] [4]
Drive level
Read Write
msec
Average – Typical [3] 6.9 7.7
Single Track – Typical [3] 0.9 1.2
Full Stroke – Typical [3] 15 16
4.2.2 Format command execution time (minutes) [1]*
ST39175
ST318275
Maximum (with verify) 20 40
Maximum (no verify) 10 20
4.2.3 Generalized performance characteristics
Data buffer transfer rate to/from disc media (one 512-byte sector):
Min. [4]* 16.2 MByte/sec
Avg. [4] 25.3 MByte/sec
Max. [4] 28.3 MByte/sec
Data buffer transfer rate to/from disc media: (< 1 track):
Min. [4] 12.2 MByte/sec divided by (interleave factor)
Avg. [4] 18.8 MByte/sec divided by (interleave factor)
Max. [4] 21.2 MByte/sec divided by (interleave factor)
*[ ] All notes for Section 4.2 are listed at end of Section 4.2.3.