The Sudden Motion Sensor (SMS) is Apple's motion-based data protection system used in their notebook computer systems. Apple introduced the system January 1, 2005 in the updated PowerBook line, and put it on the iBook line July 26, 2005. Since then, Apple has included systems in all their portable systems (since October 2006), now MacBook Pro and MacBook Air.
With a triaxial accelerometer, the shock detector detects sudden acceleration, such as when the computer is dropped, and prepares a relatively fragile hard disk drive mechanism for impact. The system releases the disk drive head from the hard disk disk, prevents data loss and damages the drive from the disk head crash. When the computer is stable, the drive is operating normally again. Clicks can be heard when the motion sensor is suddenly on.
Broadly speaking, there are two types of Sudden Motion Sensors. The sensors used in G4-based laptops resolve 1/52 g shifts (eg, near-6-bit dynamic range), while sensors used in Intel-based laptops today have 8-bit resolution (250 division scales). At least on an Intel-based laptop model, the MacBook Pro 15 ", Apple uses a Kionix KXM52-1050 three-axis accelerometer chip, with dynamic range of /- 2g and bandwidth up to 1.5Ã, kHz.
Motion sensors can also be read by programs that run on removable Apple and some programs use motion sensors to make the computer tilt awareness [1]. In this way, tilting can be used as a human interface device for example to scroll or to control the game.
Video Sudden Motion Sensor
After-sales hardware problem
Among MacBook and MacBook Pro communities there are some owners who install an aftermarket hard drive that is equipped with an anti-shock feature that reports a panic kernel error every time their unit is physically moved. This is believed to be a conflict between SMS and the new anti-shock drive function. The West Digital Scorpio notebook hard disk series has become the most frequently reported as vulnerable to this problem. In almost all cases, disabling SMS alleviates this problem without negative performance impact.
Maps Sudden Motion Sensor
Similar systems
- IBM, now Lenovo: Active Protection System, was found on several ThinkPads starting in 2003.
- Acer: GraviSense, found in some TravelMate series notebooks manufactured in 2006.
- HP: 3D DriveGuard and HP Mobile Data Protection System 3D.
- Dell: ST Microelectronics DE351DL Motion Sensor is found on XPS L401X, L501X and L701X models.
See also
- Active hard-drive protection
External links
- Apple.com: Command disables Sudden Sensor
- SeisMac: Displays the seismic data obtained from your SMS
- AMSTracker by Amit Singh Command line utility for reading data from Sudden Motion Sensor
Source of the article : Wikipedia
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