Note: The guide below is inconclusive, it appears as though he's using the drives via USB (for like pictures/videos) because he never explores any of the data... he only shows properties like 20 times.
Sonyx2302 is able to access the PS3HDD on the PC, more specifically he can Access the OtherOS (Linux) partition and OtherOSBoot partition. He were also able access those partitions just before he even installed Linux on it.
This was done by putting it into the PS3 to format it into the PS3Filesystem and than quick format it via "Fat32Formatter" on he Computer via SATA. fter that he putted the HDD back into the PS3, that recovered the Filesystem. fter that he was able to access the OtherOS partition on the Computer.
Here is the translated Tutorial:
Attention: Make a Backup of your PS3HDD before you try this!!!