Hard Drives
External hard drives can be split into four main categories:
Desktop external hard drives
These are most suitable for storing large amounts of data for the long term, when portability and easy access are not high priorities. With the largest of the hard drives on the market able to store a staggering 120 high definition (HD) movies, 1,500 games or countless photographs, one purchase could meet your data storage needs for years to come.
Portable external hard drives
Built for life on the go, portable external hard drives can be stored in jacket pockets, bags or alongside laptops. While they can hold almost as much data as the biggest desktop external drives at the top end of the market, they tend to operate more slowly, but can still comfortably store music libraries and graphic-heavy presentations. As they do not generally require a power supply, portable drives offer a plug and play alternative.
Media player hard drives
These bridge the gap between your computer and high definition (HD) television. Capable of holding vast amounts of data, these hard drives play movies and images on your television screen with an HDMI cable. The latest models can hold entire multimedia libraries and connect with other hard drives across a network.
Network hard drives
Network hard drives allow users of multiple computers to access data from a single source. A small business may use this functionality to store commonly used files in one place; while in the home, a network drive allows music to be shared across iTunes to every computer or digital media player. The largest of network hard drives on the market are capable of backing up data from multiple computers.
What to look for:
Capacity
The main selling point of a hard drive is its capacity, measured either in gigabytes (GB) or terabytes (TB). One terabyte is a thousand gigabytes. Generally, buying a hard drive with a larger capacity offers better value per gigabyte. Consider how much space you will need for your hard drive by adding up how much data you intend to store on it. If you are planning to back up an entire computer then you should buy a hard drive capable of holding all your data, and preferably more to ensure your purchase is futureproof. A typical family PC could be comfortably backed up onto a 160GB hard drive, but those working on design, multimedia or music projects may be best served by a 2TB unit to avoid running out of space.
Size
The physical size of the hard drive is largely dictated by the drive inside. Desktop external hard drives tend to contain the standard 3.5 inch drives found in PCs, whereas portable hard drives use the 2.5 inch versions usually used in laptops. A 3.5 inch drive typically needs its own power source, so may not be suitable for using on the move or anywhere that sockets are hard to find. Most portable external hard drives, equipped with 2.5 inch drives, are powered via a USB cable from your computer’s power supply, but the lack of an external power source can drain the battery and compromise performance. While bulkier desktop external hard drives are great for backing up or just freeing some space on your PC, they do not fit into briefcases or the pouches of laptop bags so easily.
Speed
Spindle speed dictates how quickly you can access data from your hard drive and is measured in revolutions per minute (rpm). A speed of 7,200rpm is more than adequate for everyday use, but if you edit a lot of videos or want to use your external hard drive for another data-hungry task like multi-track music production, then a device with a spindle speed of 10,000rpm will serve you better.
The speed at which you can transfer data is also dependent on interface, or how your drive connects to your computer. Make sure your hard drive uses an interface that is compatible with your PC before you make a purchase. USB 2.0 is normally a safe bet and can transfer data at 480mbps (megabits per second), but also works with devices which use the older and slower USB 1.1 format. The speeds provided by USB 2.0 should allow you to comfortably stream a movie from the external hard drive.
Less well-known alternatives include FireWire 800, which can transfer data at 800mbps, while the rarer eSATA ports can reach speeds of up to 3,000mbps - perfect for professional design, video and music use. Some drives and computers support more than one interface, so check to see that you are using the fastest one available to you. But be warned, the transfer speeds advertised by manufacturers can be 'optimistic’ and are dependent on the performance of your computer.
Durability
Most drives are fitted with shock protection systems to ensure they can survive bumps and shakes without any problem. However, it’s a good idea to keep your hard drive as still as possible while in use. Heavy duty users may be comforted by a drive with a built-in fan to prevent overheating, but for many portable external hard drives this is not a problem. Equally, the high quality shells of modern external drives should mean moisture and dust present no cause for concern, except in extraordinary circumstances.
Buffer memory
Picking up the slack between moving data from a hard drive to a computer, buffer memory helps increase the speed of transfers by storing small amounts of data until it can be processed. This is particularly useful for streaming video content – particularly HD pictures – from a hard drive to a computer or a television.
Auto back up
The software which accompanies an external hard drive may feature an auto back-up program, protecting you from losing valuable downloads, essential reports or vital spreadsheets. A program like this can be set up to back up automatically on a schedule, or you can use it to create a copy of your external hard drive on the drive itself, another drive, your computer or a secure internet server.
Online storage
Some manufacturers offer free online storage with their hard drives, although it is normally only a limited amount of space, perhaps up to 2GB. This can be useful to store the most essential of data, or to keep handy documents like a CV or portfolio of design work in a place where you can access it any time. You can purchase more online space from the manufacturer should you feel the need, but portable USB memory sticks generally offer the same 'access anywhere’ functionality without requiring an internet connection.
Warranty
While you can often expect a one-year warranty as standard in the event that anything unexpected goes wrong with your data storage device, some manufacturers offer longer term cover. Two years is not uncommon and a select few may offer up to a five-year warranty.
