2 articles were written in March 2013:

Since the last auto-power-off project went well, I decided to go for another problem hunting me for a while. Our satellite receivers are capable to work as PVRs when a USB disk is added. First I tried a plain USB flash stick, but its write speed was not fast enough (and with the switch to HD TV you need about 1GB per 10 minutes recording time). So I bought an external hard drive enclosure and put a 250GB drive in it.

The problem which bugged me from the beginning was that the disk stayed always on. This is not so much an issue about power consumption, but more about durability. Most disk not specifically designed for servers don’t really like to powered on always. Also, the case got noticeably warm, which also reduces the life-time of the disk.