About 5 years ago I purchased Seagate FreeAgent Desk external HDD with 1TB storage capacity. It uses an external adapter to power the hard drive and USB for data transfer. Couple of months ago I started using it with Raspberry Pi B+ for NAS, source of DLNA server media files and torrent box. Few weeks ago it started acting up, the MBR got courrpted, with a heavy heart I formatted it and after a day or two I stopped showing up Pi and PC. It had died. Without the hard drive the NAS, dlna and torrent box functionalities were useless. So just for fun I decided to have a look inside. I opened it up and found a 1TB SATA HDD and a USB to SATA converter PCB.
I had a 160 GB HDD lying around, I took out the 1TB hdd and replaced it with 160GB hdd. The size was exactly the same. Connected it back to Pi and every thing is as back as it was except the storage size. But I’m happy with it.