I've had my HX900 for several months now and have noticed that the fan and hard drive are constantly on. I guess the drive needs to be on for instant startup when programmed for recording. My concern is I know that hard drives running 24/7 will eventually fail. I also have a Replay which is exactly what happened since the fan and drive are also on 24/7. I have been able to backup and restore the image of my Replay to a new drive when the original died. Does anyone know the operating system and have a program to backup the necessary files of the drive so that a replacement drive can be created in case the original fails? The second drive in the Replay is starting to make clicking noises so I anticipate the need to replace this drive soon. Any suggestions or solutuions would be appreciated.