PC to Hard Disk Connection Types
Almost all consumer-grade external hard disks in the market today offer a USB 2.0 connection. This connection has a theoretical maximum transfer rate of 480 megabits per second or 60 megabyte per second. In practice, the rate will be about 40 megabyte per second. This speed will be enough for your data backup needs.
If you consider a faster interface, a speed that comes close to your internal hard disk’s, then you should consider e-SATA (External Serial AT Attachment, or external SATA). e-SATA theoretically supports transfers up to 3000 megabits per second (300 megabytes per second). However, the external disks having e-SATA interfaces are a little bit more expensive.
Firewire is mainly used in Macintosh computers. The numbers appearing in the name emphasizes speed in megabits, such 400, 800, 1600 and 3200. So, Firewire S1600T offers a theoretical speed of 1600 megabits per second.
Ethernet is another option, which we discussed with the network attached storage drives (NAS drives) here.
In almost all hard disks, there is the USB 2.0 connection. This may be the only one or in addition to other connection types.
This question comes into play if you want to carry your files with you. Of course, your first preference will not be to carry a bulky drive in your bag. You will be choosing something smaller and lighter. The smaller size disks use 2.5" hard disk drives, whereas larger ones use 3.5" drives.
The higher, the better.