After a pair of spoiled SD Cards, I've started to investigate what's happening with the SD cards and the Raspberry PI. Overlocking? Too many reads and writes?? Bad batchs?? At the current point of my investigation (2013-08-24) it seems that nobody knows, or at least all these problems can cause a SD corruption.

I've started this page to collect all my investigations and further directions.

• April 2013: a well docummented case in raspberrypi.org.
• March 2013: a technique to avoid data corruption by making regular checks on the sd card

I was using as a power source for the Raspberry PI an spare micro-usb charger. In fact, I've switched among chargers thinking that they were interchangeable. After this problem, I've made several investigations:

• I grabbed a good multimeter: I don't want to hear that I've didn't using the proper tools
• I measured the voltage and the current of the charges I had at home. These are my conclusions:
  • The chargers are very different in their specifications (they all have 5V output, but the current varies from 300mA to 700mA or even 1A). I've checked that my raspberry (Model B) admits 700 mA, so I think this could work

But…

One thing I've discovered is this:

• The real output voltage is 7.5 V on average ¹⁾, not 5V as especified. Probably this is because of my power line?? I din't try to guess.
• They send the power in waves: they sent a wave of 300mA of power, and they stop for a while. Then, start again. At the very first moment I've though that I've was measuring wrong, but not: I've double checked this with another multimeter and the same result. They send and stop, send and stop. This is a shot in the head for a computer (however small may be, as the raspberry), and the perfect recipe for a disk crash (like I had).

Checkout the this thread and you will find a start guide who says the following:

The unit is powered via the microUSB connector (only the power pins are connected, so it will not transfer data over this connection). A standard modern phone charger with a microUSB connector will do, providing it can supply at least 700mA at +5Vdc. Check your power supply's ratings carefully. Suitable mains adaptors will be available from the RPi Shop and are recommended if you are unsure what to use.