Product manual

Barracuda 18FC Product Manual, Rev. B 9
4.0 Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of
ST118273FC drives.
4.1 Internal drive characteristics
ST118273FC
Drive capacity 23.14 .........................Gbytes (unformatted)
18.21 .........................Gbytes (formatted with 512-byte logical blocks)
Read/write data heads 20
Bytes per track 155,000 .........................Bytes (average, unformatted)
Bytes per surface 1,165 .........................Mbytes (unformatted)
Cylinders/tracks per surface 7,501 .........................Tracks (user accessible)
Tracks per inch 8,250 .........................TPI
Internal data rate 120-190 .........................Mbits/sec (variable with zone)
Disc rotation speed 7,200 .........................rpm (± 0.5%)
Avg rotational latency 4.17 .........................msec
4.2 Seek performance characteristics
See section 9.5, “FC-AL physical interface” on page 46 and the
Fibre Channel Interface Manual (part number
77767496) for additional timing details.
4.2.1 Access time
4.2.2 Format command execution time for ≥ 512-byte sectors
Including controller overhead
1
,
2
(msec)
1. Execution time measured from receipt of the FCP command to the FCP response.
2. Assumes no errors and no sector has been relocated.
Read Write
Average Typical
3
,
4
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.
Access to data = controller overhead + average seek time + latency time.
7.9 8.7
Maximum
5
5. 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 maxi-
mum access times. The best comparison is obtained by system benchmark tests conducted under identical conditions.
Maximum times do not include error recovery.
9.3 9.6
Single track Typical
3,4
1.1 1.4
Maximum
4
1.3 1.6
Full stroke Typical
3,4
16 18
Maximum
4
18.5 20
ST118273FC
Maximum (with verify) 80 minutes
Maximum (without verify) 40 minutes