Computers have fundamentally changed the way we work, entertain ourselves, go shopping and planning our trip to the other side of the planet. We store immense quantity of data in our computer hard drive. The capacity of computer HD's was literally multiplying over the last 20 years. Today hard disk drives of 200 GB and even 450 GB are not unusual. That means you can store all your computer games, store tens of thousands of music files or hundreds of movies in a single disk. You have before you several other considerations before you purchase a hard disk.

You can easily find cheap harddrives or used hardrives for PC and desktop computers through a variety of online sources. There are different factors to consider while buying a hard disk drive. The only thing most people would ever notice is the storage capacity. In the past home computers used 40 GB hard disks, but today they have almost become obsolete.

The next is Hard disk drive speed or speed of rotation measured in RPM and a minimum of 7,200 RPM is expected. The permanent data from the memory is brought to cache memory for quick access. You may require 16MB cache or more for playing all that video games you have bought. Then there is access speed. Internal hard drives have faster access (3 ms to 15 ms) than external hard drives (80 ms to 120 ms). However you may consider an external hard disk for security and backup purposes.

External hard drives now come with capabilities of up to 250 GB ensures you can carry files or any size over to different computers. They are connected to the computer by either USB 2.0 or FireWire.

It goes without saying that the hard disk should be compatible with the operating system you use. You need to be aware of the fact that most drives are formatted for Windows based operation. If you use Mac or Linux, you will be faced with compatibility issues. You will be required to invest in different software suites to make the hard drive compatible for your operating system.