Seagate Barracuda 18XL ST318416N, Product Manual

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10 Barracuda 18XL Product Manual, Rev. A
Data buffer transfer rate to/from disc media: (< 1 track):
SCSI interface data transfer rate (asynchronous, 15 bit SCSI bus) [5]:
Maximum instantaneous 5 Mbytes/sec [6]
Maximum average 5 Mbytes/sec [7]
Target sustainable transfer rate:
Average 22
Maximum 25
Minimum 15
Synchronous transfer rate:
16 bit SE I/O data bus models 40 Mbytes/sec (Fast-40 or Ultra-2)
16 bit LVD I/O data bus models 160 Mbytes/sec (Fast-80 or Ultra160)
Sector Sizes:
Default 512 byte user data blocks
Variable 512 to 4,096 bytes per sector in multiples of 2 bytes per sector.
If n (number of bytes per sector requested) is odd, then n–1 sectors will be used.
Notes for Section 4.2.
[1] Execution time measured from receipt of the last Byte of the Command Descriptor Block (CDB) to the
request for a Status Byte Transfer to the Initiator (excluding connect/disconnect).
[2] Maximum times are specified over the worst case conditions of temperature, voltage margins and drive
orientation. When comparing specified access times, care should be taken to distinguish between typical
access times and maximum access times. The best comparison is obtained by system benchmark tests
conducted under identical conditions. Maximum times do not include error recovery.
[3] Typical Access times are measured under nominal conditions of temperature, voltage, and horizontal ori-
entation as measured on a representative sample of drives.
[4] Assumes no errors and no sector has been relocated.
[5] Rate measured from the start of the first sector transfer to or from the Host.
[6] Assumes system ability to support the rates listed and no cable loss.
[7] Simulated.
[8] Access time = controller ov average seek time
Access to data = controller ov average seek time + latency time
18.373 GB models 9.186 GB models
Min. [4] 18.5 18.5 MByte/sec
Avg. [4] 23.9 23.9 MByte/sec
Max. [4] 29.4 29.4 MByte/sec
Read/write consecutive sectors on a track Yes
Flaw reallocation performance impact (for flaws reallocated at format time using
the spare sectors per sparing region reallocation scheme) Negligible
Command overhead time for head switch in sequential mode
Command overhead time for cylinder switch in sequential mode
Command overhead, sequential read, tagged
Command overhead, sequential W/R, untagged 918
µ
sec
918
µ
sec
8
µ
sec
8
µ
sec
Average rotational latency 4.17 msec