Thread: An internal or external disk

Whether you want an internal or external disk, you'll need to consider how much information you need to store. Disks are available with capacities as small as 80GB and as large as 1 TB - that's about 1,000 gigabytes - but as a general rule, look for a disk that's twice the size of the one currently fitted in your computer. 500GB disks are reasonably priced and should give you enough room for several years of use.
If you want to add a new internal hard disk you'll need to check that there's room for it inside your PC. This means that you'll need a spare slot inside your PC's case. Most cases have several slots inside but if you're unsure, it's worth opening the case and having a look for a free one next to your existing hard disk. Almost all desktop computers use hard disks that are 3.5in wide, while notebooks use smaller 2.5in disks. These smaller disks are more expensive and trickier to fit inside a desktop PC, so be sure to buy a 3.5in model.

You'll also need to find out what kind of cables are used to connect the hard disk to your computer. Hard disks need to be connected to two cables: one supplies power and the other carries information between the disk and the rest of the PC. Modern PCs use one of two different types of interface to carry information: PATA or SATA. PATA uses wide ribbon cables with an equally wide plug at either end, while SATA uses thinner cables that are only about a centimetre wide.



PATA cables are usually grey, often with blue plugs at the end, while SATA cables are usually brightly coloured with black plugs. If you can't work out what type of cable is connected to your existing disk then check your computer's manual: PATA is sometimes referred to as IDE or ATA. The majority of modern computers use SATA, so we'll install a SATA disk in this article, but the process when installing a PATA disk is almost identical.

In the mini Workshop overleaf we'll show you how to install a second hard disk into a typical home PC - we used a Dell Dimension. Some shops sell hard disks in fancy packaging with extra software and cables, while others send just the disk itself. We used the latter.