Are you running low on hard disk space? Then you’ll need to buy an external hard drive or get and additional internal hard drive with a 3.5 inches form factor (for desktop systems and servers) or one with a 2.5 inches form factor (for notebooks). You should take into account the connection interface, so that you can avoid the motherboard incompatibility problems. Also, depending on the motherboard, you will have to choose a hard disk compatible with the spindle speed and the transfer rate. In order to avoid any further upgrades in the near future make sure that you acquire a device with high storage capacity.