The trend with technology seems to be going small and mobile. You would probably think that is where the manufacturers got the idea of making external hard drives. These are hard disk drives (HDD) that are literally placed outside of the computer case. An external HDD does not only give you more space, but it provides you with mobility. With the option to remove this HDD, you are able to take all your data with you.

There are external HDD that are built to be external, meaning the HDD has built-in cables that allow you to interface with your computer. Older connectors would use SCSI or SATA cables that connect to a type of HDD connector inside your computer. Newer versions of external HDD uses a simpler method by simply connecting via the USB or the FireWire. Some external HDD provide you with the ability to backup the data from your computer. Although an external HDD gives you the mobility, they tend to be more expensive as compared to the internal versions with the same capacity.

As an alternative to these external HDD, manufacturers have developed an HDD casing that allows you to convert your internal HDD, whether it is a 3.5 drive or a 2.5 drive, to external HDD. You would have to purchase this casing separately, but the advantage is that with this type of casing, you can easily upgrade your HDD without hassle. What differentiates an external 3.5 drive from a 2.5 drive is that normally, the larger device would need an extra power source, while the 2.5 can be supported by the power coming from the USB or FireWire.

A more corporate version of an external HDD is a Network Access Storage (NAS). This device is connected directly to you network so you do not need to have a host computer to access the data in it. NAS also allows multiple users to access the data concurrently without using the resources of a host computer.