IBM IC25N020ATDA04 Hard Drive Specifications - Page 47

Power switch design considerations, 4.6.4 Test considerations

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This power-down sequence should be followed for entry into any system power-down state, system suspend state, or system hibernation state. In a robustly designed system, emergency unload is limited to rare scenarios, such as battery removal during operation. 6.4.6.3 Power switch design considerations In systems that use IC25XXXXATDAxx-x consideration should be given to the design of the system power switch. IBM recommends that the switch operate under control of the BIOS, as opposed to being hardwired. The same recommendation is made for cover-close switches. When a hardwired switch is turned off, emergency unload occurs, as well as the problems cited in Section 5.1, "Data loss on power off" on page 21 and Section 5.2, "Write Cache" on page 21. 6.4.6.4 Test considerations Start/stop testing is classically performed to verify head/disk durability. In the case of IC25XXXXATDAxx-x the heads do not land on the disk, so this type of test should be viewed as a test of the load/unload function. Start/Stop testing should be done by commands through the interface, not by power cycling the drive. Simple power cycling of IC25XXXXATDAxx-x invokes the emergency unload mechanism and subjects the HDD to nontypical mechanical stress. Power cycling testing may be required to test the boot-up function of the system. In this case IBM recommends that the power-off portion of the cycle contain the sequence specified in Section 6.4.6.2, "Required Power-Off Sequence" on page 32. If this is not done, the emergency unload function is invoked and nontypical stress results. Travelstar 48GH, 30GN & 15GN hard disk drive specifications 33

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This power-down sequence should be followed for entry into any system power-down state, system
suspend state, or system hibernation state. In a robustly designed system, emergency unload is limited
to rare scenarios, such as battery removal during operation.
6.4.6.3 Power switch design considerations
In systems that use IC25XXXXATDAxx-x consideration should be given to the design of the system
power switch.
IBM recommends that the switch operate under control of the BIOS, as opposed to being hardwired. The
same recommendation is made for cover-close switches. When a hardwired switch is turned off,
emergency unload occurs, as well as the problems cited in Section 5.1, "Data loss on power off" on
page 21 and Section 5.2, "Write Cache" on page 21.
6.4.6.4 Test considerations
Start/stop testing is classically performed to verify head/disk durability. In the case of
IC25XXXXATDAxx-x the heads do not land on the disk, so this type of test should be viewed as a test of
the load/unload function.
Start/Stop testing should be done by commands
through the interface, not
by power cycling
the drive.
Simple power cycling of IC25XXXXATDAxx-x invokes the emergency unload mechanism and subjects
the HDD to nontypical mechanical stress.
Power cycling testing may be required to test the boot-up function of the system. In this case IBM
recommends that the power-off portion of the cycle contain the sequence specified in Section 6.4.6.2,
"Required Power-Off Sequence" on page 32.
If this is not done, the emergency unload function is
invoked and nontypical stress results.
Travelstar 48GH, 30GN & 15GN hard disk drive specifications
33