Since this topic is posted very often in Tech, I thought I'd make a quick guide to external hard drives.
External hard drives are a great way to add extra storage to a laptop or desktop and brilliant for making backups (which I strongly reccomend you do every week).
Types Of External Hard Drive
There are 2 main types; desktop and portable.
Desktop drives use a full 3.5" (usually 7200rpm) hard drive and offer good value for money and large capacities. They need a mains power supply.
Portable drives use smaller laptop 2.5" hard drives (either 4200 or 5400rpm). They cost more than a similar capacity desktop drive, but fit in a pocket and great for carrying around important work/documents you need frequently. The advantage is that most do not need an external power supply because they get it from USB or Firewire (6 pin) ports. Some drives may need more power and supply an extra USB cable to get power from another port. If you use 4 pin firewire, then you will need extra power.
You can also get even smaller 1.8" drives (such as ones used in iPods and ultraportable laptops), but they cost more.
Interface
There are 2 main types of connection used for external hard drives; USB and Firewire.
USB 2.0 is the most common. All modern desktops and laptops have USB 2.0 ports and they offer good speed for data transfer. It is also backwards compatible with USB 1 ports (and runs at a lower speed).
Firewire 400 ports are found on most desktops and laptops (apart from budget models). For desktops, you can get PCI firewire cards cheaply. Firewire 400 is faster than USB 2.0 for sustained transfer and therefore better for video work and transferring large amounts of data. There are 6 pin (powered) and 4 pin (unpowered) variants of Firewire 400. Most desktops tend to have 6 pin, while laptops tend to use 4 pin. All Apple laptops have 6 pin firewire.
There is also Firewire 800, which uses a 9 pin connector. It is twice as fast as Firewire 400, and good for people who do lots of heavy video work or transfer huge files regularly. You can get Firewire 800 PCI card for desktops, but they aren't commonly found on laptops apart from Apple PowerBooks (15/17" G4) and MacBook Pros (Core 2 Duo versions). You can get leads to connect Firewire 400 (4 or 6 pin) to Firewire 800 ports.
Capacity
You can never have too much hard drive capacity and it is best to buy the biggest you can afford. You may think that you will never fill it up, but it can be useful for backups or temporary storage.
1GB can hold approximately:
16 hours of 128kbps MP3 (about 240 songs of average 4 mins)
About 2 hours of DIVX/XVID movies
About 350 average JPEG 6 megapixel photos
4 minutes of DV video (imported from a DV camcorder)
What Drive To Buy
Generally as long as you stick to a good brand then you should be fine. Western Digitals seem very popular and reliable, especially their MyBook and Passport ranges, so you can't go wrong with them. Also, Seagate are known to be reliable. Avoid brands like Maxtor (I personally have had several of their drives fail), and any unbranded cheap drives. They tend to use poor quality components and low quality drives that are more likely to fail.
Western Digital MyBooks
Here are some good deals currently (prices correct at time of writing, 05/06/2007)
Essential USB 2.0 connection, black with green activity lights
250GB,
£54.99 from Amazon
320GB,
£64.07from Amazon
500GB,
£89.99 from Amazon
Premium USB 2.0 and Firewire 400 connection, black with blue activity and capacity lights
250GB,
£70.50 from Amazon
320GB,
£80.76 from Amazon
Pro USB 2.0, Firewire 400 and Firewire 800 connection, silver with blue activity and capacity lights
500GB,
£115.42 from eBuyer (Just 18p more than the Premium 500GB at Amazon!) Don't forget Google Checkout for £10 discount from eBuyer.
1TB,
£239.11 + £7 Delivery from Dabs (Twice the width of other MyBook drives because it uses 2 hard drives.)
Passport USB 2.0 connection, black with blue activity light
60GB,
£40.97 from Amazon
120GB,
£52.86 from Amazon
160GB,
£69.99 from Amazon
