> What does Backplane
> Ready refer to?
I believe that it means that it fits a 3.5" form factor (the connectors
are located as if it was a 3.5"-sized drive).
It refers to the interface type. "Backplane Ready" drives are intended
for installation in external, multi-drive enclosures, usually for RAID
and hot swap purposes.
Long story short: if you're buying the drive for a desktop computer
and not an external multi-drive enclosure, you need the standard
"SATA cable connect" version.