How to protect the harddisk through APS
|
This page tells you how to make the Active Protection System work under Linux to protect your harddrive from damage in case of a notebook drop or other kind of impact while it is running. |
How APS works in Linux
APS in Linux consists of four components on the software side:
- The HDAPS driver (included in recent kernels).
- The hdaps_protect disk protection kernel patch (available for kernel 2.6.15 and for kernel 2.6.16; see here for other versions)
- The hdapsd disk protection userspace daemon
- Optional: the khdapsmon KDE System Tray applet or the gnome-hdaps-applet.
The HDAPS driver exports a sysfs interface providing the acceleration values.
The hdaps_protect kernel patch xports a sysfs interface that enables an ide or sata disk to be protected by a userspace process.
The hdapsd userspace daemon monitors the acceleration values through the HDAPS interface and automatically initiates disk protection through the hdaps_protect interface - given that the movement exceeds a user specified threshold.
Finally the applets are providing a visual indication of the disk protection status and provide a graphical interface for adjusting configuration options for hdapsd.
Installation
As mentioned above, the hdaps kernel driver found in recent kernels 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.
- Download and build the latest hdaps_protect disk protection kernel patches.
- Enable the drivers in the kernel (requires kernel rebuild).
- Download, build and configure the hdapsd userspace daemon.
- Download and build one of the applets to get a real-time representation of the disk protection status.
Getting the files
The latest versions of hdaps_protect, hdapsd and the gnome-hdaps-applet are available at [1]..
khdapsmon can befound here.
Debian source and sid binary packages for hdapsd and the hdaps_protect patches (kernel-patch format) are available via APT access:
deb http://www.oakcourt.dyndns.org/debian/ ./ deb-src http://www.oakcourt.dyndns.org/debian/ ./
Patching the kernel and enabling the drivers
As root go to /usr/src/linux
# patch -p1 < ~/hdaps_protect.20060118.patch
|
TODO
|
tell about how to patch the kernel and what needs to be enabled afterwards
|
Problem with unload capabilities check
After installation, you may get the following kernel message when the disk is protected (e.g., via # echo 1 > /sys/block/sda/queue/protect):
ata_scsi_issue_protect_fn(): unload support NOT reported.. scsi_protect_queue(): head park not requested, used standby!..
or
idedisk_issue_protect_fn(): unload support NOT reported.. ide_protect_queue(): head park not requested, used standby!..
If you see this, and you are sure that your drive actually does support unloading (all original drives sold with HDAPS-equipped ThinkPads do), then add the following patch on top of the above patch:
diff -u linux-2.6.15.hdaps/drivers/ide/ide-disk.c linux-2.6.15.hdaps/drivers/ide/ide-disk.c --- linux-2.6.15.hdaps/drivers/ide/ide-disk.c 2006-01-18 07:11:54.000000000 +0000 +++ linux-2.6.15.hdaps/drivers/ide/ide-disk.c 2006-01-18 07:11:54.000000000 +0000 @@ -869,7 +869,7 @@ else printk(KERN_DEBUG "idedisk_issue_protect_fn(): unload support NOT reported..\n"); - return ide_protect_queue(q, (drive->id->cfsse & (1 << 13)) ? 1: 0); + return ide_protect_queue(q, 1); } int idedisk_issue_unprotect_fn(request_queue_t *q) diff -u linux-2.6.15.hdaps/drivers/scsi/libata-scsi.c linux-2.6.15.hdaps/drivers/scsi/libata-scsi.c --- linux-2.6.15.hdaps/drivers/scsi/libata-scsi.c 2006-01-18 07:15:31.000000000 +0000 +++ linux-2.6.15.hdaps/drivers/scsi/libata-scsi.c 2006-01-18 07:15:31.000000000 +0000 @@ -661,7 +661,7 @@ printk(KERN_DEBUG "ata_scsi_issue_protect_fn(): unload support NOT reported..\n"); /* call scsi_protect_queue, requesting either unload or standby */ - return scsi_protect_queue(q, ata_id_has_unload(dev->id) ? 1 : 0); + return scsi_protect_queue(q, 1); } static int ata_scsi_issue_unprotect_fn(request_queue_t *q)
Drives on which the capabilities check patch is needed
- Hitachi HTS726060M9AT00 (7K60) on ThinkPad T43
Installing hdapsd
|
TODO
|
tell how to build hdapsd
|
Configuring hdapsd
|
TODO
|
tell how to configure hdapsd
|
Building an applet
Building khdapsmon
|
TODO
|
tell people what to do
|
Building gnome-hdaps-applet
|
TODO
|
tell people what to do
|
Further Information
- Additonal information and support is available through the hdaps-devel mailinglist and its archive.
