Hi Gwenaelle,

Generally it indicates that the OS was unable to read data from a storage subsystem (disk drive).

There can be several reasons for this:
Poor cables: thermal expansion and contraction of cable connectors between a hard drive and a SATA port can make and break the connection. The device will see this as being unplugged while it is in use. Some electronic devices will refuse to reconnect (or just become confused until reset).
Often you can fix this by replacing the cables or work around this by going into the BIOS and enable hotswap for the port that your drive is on. This tells the OS to expect to get disconnected.( still get disconnected but it auto reconnects so you only get stupid little pauses rather than a crashed OS)

other things:

1. Update BIOS lots of bugs in various versions of BIOS that effect drive controllers. Your problem might go away with a BIOS update.
2. If that fails to fix the problem, then you need to update the chipset drivers for your CPU.
3. Try a different sata port or second controller if your system has one (lots of funky hardware, I had systems that the sata 2 would go deaf after a few hours but the sata 3 worked great.
4. If all these fail then start to look at your actual drive, sometimes you will get event log errors from the disk subsystem that indicates that the drive took too long to respond. This can mean, bugs in the electronics of the drive (sometimes you can turn off lazy writes and things will work after that) sometimes you can get firmware updates for your drive.
5. Windows 8 was the first windows OS to turn on Low power management by default. You can turn off the feature in control panel under the power management options for the drive and that might help.

Thank You!
Lokesh