Potential data loss on SD cards bigger than 256 MBytes

FAQ #101377

 

Symptom
Under certain circumstances data losses on SD cards bigger than 256 MBytes have been observed. By analyzing these reports we have seen that in case more than 70% of the available memory on such a card is used it is possible that data is lost on the next power-up of the PCD or after the card has been re-inserted into the memory module holder (R600 / R6000) or opened by the SD Flash Explorer.
In case of many delete operations executed by the module the mentioned data loss can also occur if less than 70% of the available memory is used (due to the ware-out management of the SD card which varies the used memory areas).

Solution
An additional safety mechanism in the PCD firmware 1.10.51 as well as in the SD Flash Explorer in order to avoid future potential data loss on concerned cards has been implemented.
As soon as the system is rebooted (or the SD card is re-inserted into the R600 / R6000 mounted on a PCD with a new firmware versions) actions are taken in order to avoid the mentioned potential data loss.

The according firmware 1.10.51 (for PCD2.M5xx0 and for PCD3.Mxxx0 systems) with the new safety mechanism can be found on the support site www.sbc-support.ch.

In addition to the safety mechanism a new SD Flash Explorer version 2.0.215.0 features a “Backup” and a “Restore” feature which allows the creation of a backup of the file system.
This SD Flash Explorer can be downloaded from the support site from the section for the PCD7.R-SDxxx and will be distribued with the SP1 for PG5 2.0.

Remarks

• Even if the file system on a SD card is already filled up by more than 70%, it is still possible to download the data over FTP as long as the PCD is NOT switched off. This method is recommended before updating the firmware in order to guarantee that no data is lost.
• SD cards delivered by Saia-Burgess Controls AG after week7 of 2010 contain a mechanism that avoids the above mentioned data loss (as long as the card is not formatted with a firmware older than 1.10.51).