Bureaucrats, dave_user, Administrators
4,650
edits
Changes
no edit summary
== Example: embedded Linux system equipped with an e.MMC ==
TBD
As explained [[#Device's built-in advanced functionalities|here]], the health status registers can be exploited to implement a monitoring mechanism. For example, a user-space application may poll periodically the status of the device and take actions accordingly if the wear-out exceeds predefined thresholds.
As explained in [[#Embedded Linux systems with eMMC or SD cards|this section]], e.MMC's feature specific registers for monitoring the health of the device. Following is a dump of the standard registers of the target's e.MMC regarding the wear-out status of the device, namely <code>DEVICE_LIFE_TIME_EST_TYP_B</code>, <code>DEVICE_LIFE_TIME_EST_TYP_B</code>, and <code>PRE_EOL_INFO</code>:<pre class="board-terminal">
root@desk-mx8mp:~# mmc extcsd read /dev/mmcblk2 | grep LIFE
eMMC Life Time Estimation A [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]: 0x01
eMMC Life Time Estimation B [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_B]: 0x01
root@desk-mx8mp:~# mmc extcsd read /dev/mmcblk2 | grep EOL
eMMC Pre EOL information [EXT_CSD_PRE_EOL_INFO]: 0x01
</pre>Some manufacturers use additional proprietary registers for providing information about the amount of data that have been actually written onto the device. If available, this number allows to calculate the WAF as the amount of data written by the applications of the test workload is known as well.
Last but not least, it is worth remembering that advanced, proprietary tools may also be available for health monitoring. For instance, Western Digital provides such tools for its devices. For more information, please contact our [mailto:sales@dave.eu Sales Department].
= References =
