External hard disk can be hook up to your computer in many ways. The most commonly used interface would be USB. Some of them might come with a USB cable split into two at the other end. This is to ensure that sufficient power is being supplied to your external hard disk. Just as connecting a thumb drive to a computer, you just need to plug in the cable to the corresponding USB port on your computer. If your external hard disk has a firewire interface, use it. Although firewire 400 has a lower rated transfer rate as compared to USB's rated 480 Mbps bandwidth, firewire 400 promises faster overall transfer speed as it has a higher sustainable transfer rate as distortion of signals do not occur as often as USB. Other than that, eSata is another interface. As its name implies, it is being derived from the ubiquitous SATA interface. It beats USB and Firewire 400/800 in terms of transfer speed. However, one drawback is that eSata does not supply power to the connecting device. Therefore, you have to hook up another cable to the main power socket for the hard disk to function properly.
Thanks a lot both of you, that's all I needed to know - I think!
I plan to use it to store some of the stuff that I need less often when my hard drive fills up a bit more. I've had to burn a whole load of files to DVDs to make room a few weeks ago, but that's not convenient for files I might want to change at some point. Thus, I won't use it constantly like an extension of my normal hard drive but only when I need it. I'm glad you told me about the shortened life, Byakuya_Kuchiki, that's very useful.
For the reasons you mentioned, the choice for an external USB hard disk seems reasonable to me... If you use it as an archive or back-up (seems like WORM) and accidentally change a file, you will have some pleasure with it...
why not an internal HD? may be cheaper
Ninjakannon, I take it you don't have room in your case for two harddrives? What I am going to do when my laptop arrives is take out my internal 200gb 3.5" hdd and put it in an external case for $20, save some money that way; while in the long term you may be better of buying a pre-configured external hdd (depending on the hdd safety features and padding) or save some cash and buy an internal drive on sale and an external case for it (make sure that you match an ultra ata drive with a corresponding case and the same for sata). There are also eSATA externals from what I understand but don't have experience with them.
Oh it's all so complicated! Heh, computing issues - with software or hardware can both end having far more to them than you first realised. I like the idea of being able to take the external hard drive to another computer easily as I sometimes need to copy large amounts of data from one computer to another. Using an external hard drive just sounds more useful than adding another internal one.