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10
SCSI interface data transfer rate (asynchronous) [5]:
Maximum instantaneous
Maximum average
Synchronous transfer rate for SCSI Fast-20 (Ultra-1 SCSI):
Synchronous transfer rate for SCSI Fast-40 (Ultra-2 SCSI):
Synchronous transfer rate for fast SCSI-2:
Sector Sizes:
Default
Variable
Read/write consecutive sectors on a track
Flaw reallocation performance impact (for flaws reallocated at format time using
the spare sectors per sparing region reallocation scheme.)
Overhead time for head switch (512 byte sectors) in sequential mode
Overhead time for one track cylinder switch in sequential mode
Average rotational latency
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 overhead + average seek time
Access to data = controller overhead + average seek time + latency time
4.3
Start/stop time
After DC power at nominal voltage has been applied, the drive becomes ready within 30 seconds if the Motor
Start Option is disabled (i.e. the motor starts as soon as the power has been applied). If a recoverable error
condition is detected during the start sequence, the drive executes a recovery procedure which may cause the
time to become ready to exceed 30 seconds. During spin up to ready time the drive responds to some com-
mands over the SCSI interface in less than 1.5 seconds after application of power. Stop time is less than 20
seconds from removal of DC power.
If the Motor Start Option is enabled, the internal controller accepts the commands listed in the SCSI Interface
Product Manual less than 3 seconds after DC power has been applied. After the Motor Start Command has
been received the drive becomes ready for normal operations within 25 seconds typically (excluding an error
recovery procedure). The Motor Start Command can also be used to command the drive to stop the spindle
(see SCSI Interface Product Manual, part number 77738479).
There is no power control switch on the drive.
Barracuda 50 Product Manual, Rev. C
6.0 Mbytes/sec [6]
6.0 Mbytes/sec [7]
40 Mbytes/sec
80 Mbytes/sec
20 Mbytes/sec
512 byte user data blocks
512 to 2,048 bytes per sector in multiples of 4
bytes per sector.
If n (number of bytes per sector requested) is
odd, then n-1 sectors will be used.
Yes
Negligible
1.2 msec
1.2 msec (typical)
4.17 msec (calculate)
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