The ATA and SCSI interfaces have evolved to include many sub-types, which may or may not be backwardly compatible.
Capacity is the amount of data that the drive can store, after formatting.
The drive Model number is Seagate's unique identifying code for each drive. The model number reflects the drive's form factor, capacity, and interface. The faster the spin rate, the less time it takes for the drive to read or write a given amount of data. It includes controller overhead but does not include drive latency. System Type describes the type of computer system in which this drive would most likely be used.