We won't really know until we see the smart reports. The "timeout" error and hard reset could be a cabling issue, or a power supply issue, or a disk itself, or a disk controller?
The buffer I/O errors look more like unreadable sectors... I've not see them before. we'll know for sure when you get the end smart report.
Joe L.
I saw the same errors with 1 of my 3 WD20EARS disks in the first preclear cycle. They were gone the second time. Smart reports were fine both times.