Seagate ST373405LW/LWV/LC/LCV ユーザーズマニュアル
Cheetah 73LP Product Manual, Rev. E
15
5.2.6
Hot plugging Cheetah 73LP disc drives
The ANSI SPI-3 (T10/1302D) document defines the physical requirements for removal and insertion of SCSI
devices on the SCSI bus. Four cases are addressed. The cases are differentiated by the state of the SCSI bus
when the removal or insertion occurs.
devices on the SCSI bus. Four cases are addressed. The cases are differentiated by the state of the SCSI bus
when the removal or insertion occurs.
Case 1 - All bus devices powered off during removal or insertion
Case 2 - RST signal asserted continuously during removal or insertion
Case 3 - Current I/O processes not allowed during insertion or removal
Case 4 - Current I/O process allowed during insertion or removal, except on the device being changed
Seagate Cheetah 73LP disc drives support all four hot plugging cases. Provision shall be made by the system
such that a device being inserted makes power and ground connections prior to the connection of any device
signal contact to the bus. A device being removed shall maintain power and ground connections after the dis-
connection of any device signal contact from the bus (see T10/1302D SPI-3 Annex C).
such that a device being inserted makes power and ground connections prior to the connection of any device
signal contact to the bus. A device being removed shall maintain power and ground connections after the dis-
connection of any device signal contact from the bus (see T10/1302D SPI-3 Annex C).
It is the responsibility of the systems integrator to assure that no hazards from temperature, energy, voltage, or
ESD potential are presented during the hot connect/disconnect operation.
ESD potential are presented during the hot connect/disconnect operation.
All I/O processes for the SCSI device being inserted or removed shall be quiescent. All SCSI devices on the
bus shall have receivers that conform to the SPI-3 standard.
bus shall have receivers that conform to the SPI-3 standard.
If the device being hot plugged uses single-ended (SE) drivers and the bus is currently operating in low voltage
differential (LVD) mode, then all I/O processes for all devices on the bus must be completed, and the bus qui-
esced, before attempting to hot plug. Following the insertion of the newly installed device, the SCSI host
adapter must issue a Bus Reset, followed by a synchronous transfer negotiation. Failure to perform the SCSI
Bus Reset could result in erroneous bus operations.
differential (LVD) mode, then all I/O processes for all devices on the bus must be completed, and the bus qui-
esced, before attempting to hot plug. Following the insertion of the newly installed device, the SCSI host
adapter must issue a Bus Reset, followed by a synchronous transfer negotiation. Failure to perform the SCSI
Bus Reset could result in erroneous bus operations.
The SCSI bus termination and termination power source shall be external to the device being inserted or
removed.
removed.
End users should not mix devices with high voltage differential (HVD) drivers and receivers and devices with
SE, LVD, or multimode drivers and receivers on the same SCSI bus since the common mode voltages in the
HVD environment may not be controlled to safe levels for SE and LVD devices (see ANSI SPI-3).
SE, LVD, or multimode drivers and receivers on the same SCSI bus since the common mode voltages in the
HVD environment may not be controlled to safe levels for SE and LVD devices (see ANSI SPI-3).
Caution.
The disc drive spindle must come to a complete stop prior to completely removing the drive from
the cabinet chassis. Use of the Stop Spindle command or partial withdrawal of the drive, enough to
be disconnected from the power source, prior to removal are methods for insuring that this require-
ment is met. During drive insertion, care should be taken to avoid exceeding the limits stated in
Section 6.4.4, “Shock and vibration” in this manual.
the cabinet chassis. Use of the Stop Spindle command or partial withdrawal of the drive, enough to
be disconnected from the power source, prior to removal are methods for insuring that this require-
ment is met. During drive insertion, care should be taken to avoid exceeding the limits stated in
Section 6.4.4, “Shock and vibration” in this manual.
5.2.7
S.M.A.R.T.
S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended
to recognize conditions that indicate imminent drive failure and is designed to provide sufficient warning of a
failure to allow you to back up the data before an actual failure occurs.
to recognize conditions that indicate imminent drive failure and is designed to provide sufficient warning of a
failure to allow you to back up the data before an actual failure occurs.
Note.
The drive’s firmware monitors specific attributes for degradation over time but can’t predict instanta-
neous drive failures.
neous drive failures.
Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating per-
formance of the drive and the thresholds are optimized to minimize “false” and “failed” predictions.
formance of the drive and the thresholds are optimized to minimize “false” and “failed” predictions.
Controlling S.M.A.R.T.
The operating mode of S.M.A.R.T. is controlled by the DEXCPT and PERF bits on the Informational Exceptions
Control mode page (1Ch). Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEX-
CPT bit disables all S.M.A.R.T. functions. When enabled, S.M.A.R.T. collects on-line data as the drive performs
normal read and write operations. When the PERF bit is set, the drive is considered to be in “On-line Mode
Only” and will not perform off-line functions.
Control mode page (1Ch). Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEX-
CPT bit disables all S.M.A.R.T. functions. When enabled, S.M.A.R.T. collects on-line data as the drive performs
normal read and write operations. When the PERF bit is set, the drive is considered to be in “On-line Mode
Only” and will not perform off-line functions.