I created a dos/mbr partition table and some partitions using gparted, on a hard drive I connected to my laptop via a SATA-USB interface. I then placed the hard drive in my system hard drive bay and booted the system using a live USB. When I opened gparted, it did not recognize the partition table. I then created another partition table with the hard drive in the laptop's hard drive bay. When I removed the hard drive from the bay and connected it to my laptop via a SATA-USB interface, gparted was also not able to recognize the partition table. In both cases however, gparted was able to recognize the partition table on the hard drive, if I connect it to my laptop via the same interface with which I had created the partition table.
My question is how does the system differentiates between a partition table created in the hard drive bay and via a SATA-USB interface?