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HDAPS - IBM Active Protection System Linux Driver

This is the Linux driver for monitoring the acceleratometer known as IBM Active Protection System.

The driver only enables reading of the acceleration data. It does not perform automatic disk head parking. But there are already some other useful applications for HDAPS, using the /sys interface it provides.


  • provides accelerometer values via sysfs
  • provides a joystick type input device

Project Homepage / Availability

  • Project Homepage
  • The driver is included in the 2.6-mm series of kernels since August, 26th 2005.
  • The driver is now in the mainline (2.6.14). (use as modul if you want use tp_smapi, Gentoo and X41)


A driver is included in recent Linux kernels and is actively maintained.

Harddisk Protection

As mentioned above, the hdaps kernel driver is only responsible for reading the accelerometer data and exporting it through the sysfs interface. In order to use this information to protect the disk, some additional steps are required.

See How to protect the harddisk through APS.

Input device support

The hdaps driver in the lastest kernels (2.6.14 and later?) also exports a joystick type input device, which can be used by games.


Disk head parking

See How to protect the harddisk through APS for more information.

Security & safety

Tilt monitoring

  • gkhdaps a GKrellM applet displaying tilt data
  • gnome-tilt a gnome applet showing tilt data

Visualisation (of ThinkPad orientation)


  • Robert Love mentions a Neverball patch on his blog to keep the display aligned. However, the link there seems broken.

Interesting links related to this project