A hard drive reader is a device that can connect to a computer and allow hard drives that are designed to be internal devices to be effectively used as external memory. This type of device can be quite useful for someone who has upgraded a computer and may have extra hard drives from older computers that still have data on them. These devices can be simple adapter cords that connect to a hard drive and plug into a universal serial bus (USB) port on a computer, or hardware that allows a drive to be docked onto the device. A Hard Disk Reader typically allows a hard drive to then function like a fairly portable mass media device.
Sometimes called an external enclosure, a hard drive enclosure allows a computer user to access data on an internal hard drive that is no longer inside a computer. A hard drive is a form of physical memory storage that allows a computer user to save data, such as programs and files. Internal hard drives cannot typically be accessed from outside a computer, unless some type of reader is used. There are two primary ways in which these devices can work, which is to either simply be an adapter cable or as a piece of hardware to which a hard drive connects.
An adapter cable can be used to allow a user to connect one end to the pin connectors of an internal hard drive and the other end to a USB port on a computer. Since the USB can also transfer power to a device, these adapters can sometimes provide the power necessary for the hard drive to run, though a power adapter for the drive may also be necessary. The connected hard drive will then appear as an external media device on the computer, and the data on it can be accessed accordingly.
A external hard drive enclosure can also be a piece of hardware that a hard drive can be connected to, allowing it to interface with a computer. This is typically done through a USB port as well, but rather than just a cord, there is usually a docking station or enclosure for the hard drive. The connector on the hard drive is connected to the enclosure or dock and the device is connected to the computer. This type of reader usually works much like the connector cable, and the drive will appear as external memory. These readers can be more stable than an adapter cable, however, so frequent hard drive reading can benefit from such a device.