Start with the determination of a suitable form factor hard drive. Standard models have a width of 3.5 or 2.5 inches. External hard driveand the first category are very bulky and heavy. Sometimes such devices require connection to AC mains. This feature doesn't allow to use them in conjunction with mobile PC outdoors.
Note the amount of memory the hard disk. Device with form factor of 3.5 inches, as a rule, allow you to record more information than their smaller counterparts. If you value this feature, select the 3.5 inch hard drive.
Do not forget to learn another important feature is the processing speed. Keep in mind not only the direct write speed to disk, but the bandwidth of information exchange between hard drive and PC. High speed data transfer provide USB 3.0 and eSATA.
Find out the presence of connectors required for connection with other devices. In most cases, you use the USB port. With it, you will be able to connect the hard drive not only to computer but also TV, sound system and so on.
Examine the appearance of the hard disk. Find out what material it is made of the case. Often you can find hard disks with a metal sheath. The case well protects the drive from external influences.
Remember that certain models of removable hard drives require an active connection the two USB channels. Usually after one of them passed information, and through other food. If you plan to use the hard drive with mobile computer, avoid buying a hard driveand with the specified feature. First, you can always connect additional peripherals. And secondly, like the winchesters actively consume battery power.