Seagate HAWK 4, Product Manual

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Product Manual - Hawk 4 Family SCSI-2 (Volume 1), Rev. F 11
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5.3.1 Notes for sections 5.2 and 5.3.
[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
orientation 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 the Initiator immediately sends Write Data to the drive when requested.
[7] Command execution requires a data transfer phase (data to or from the disc media). Assumes the initia-
tor is instantly ready to send/receive the data when the drive generates first request for a data byte
transfer, and assumes an average data transfer rate between the drive and the Initiator as specified in
section 5.3.
[8] All performance characteristics assume that automatic adaptive temperature compensation is not in
process when the SCSI command is received. The following paragraphs give highlights of thermal cali-
bration operation.
a.
At spin-up, all heads are calibrated on the outer and inner diameter calibration tracks.
b. A timed calibration occurs 1 minute after spin-up, and every 10 minutes thereafter. During these
timed calibrations, the firmware alternates between the inner and outer diameter calibration tracks.
For example, all heads are calibrated on the inner track, then 10 minutes later all heads are cali-
brated on the outer track. Automatic adaptive temperature calibration does not interrupt SCSI com-
mands being executed.
c. If automatic adaptive thermal calibration is in process when the drive receives a SCSI command, the
drive queues the command until the compensation for the specific head being compensated com-
pletes. When compensation completes for the specific head being compensated, the drive executes
the first queued command. When execution of the first queued command completes, the drive con-
tinues compensation for the remaining head(s). The above procedure continues until the drive com-
pletes compensation for all heads.
d. When a timed calibration comes due, the drive postpones the calibration until the drive has been idle
for 25 to 50 milliseconds.
e. When the drive receives a Write command, the drive performs a single head calibration if a calibra-
tion has been delayed for 1 to 5 minutes. The drive performs an uninterruptible calibration of all heads
if the calibration has been delayed more than 5 minutes.
f. The drive preforms a calibration of all heads prior to the first retry of any media error if a timed
calibration has been delayed for over one minute.
g. Automatic adaptive temperature compensation takes less than 0.1% of bus time.
h. Automatic adaptive temperature compensation occurs at times other than mentioned above, but
should be transparent to the user (e.g., during execution of Format, Rezero, and Reassign Block
commands).
i. A rezero command can be used to reset the Automatic adaptive temperature compensation timer
back to start so that the host can know when the interruption for timed thermal compensation will
occur.
[9] Assumes system ability to support 5.2 Mb/s and no cable loss.
[10] Simulated.
[11] Assumes Typical host delays and cable losses.
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*SCSI Interface commands described in SCSI Interface Manual 77738479.