Portable external hard drives are becoming more and more popular these days — and why not?  With their small form-factor (mine is 0.7″h x 5″l x 3.2″w and 0.4 pounds) and price (anywhere from $150-$200 for a 500Gb drive), they make ideal data storage units, especially for transfering data on the road.  I recently took one on the road for a photography assignment, and one nice thing about them (of many — I love them!) is that you may not need to lug your laptop around!  Many hotels have “data centers” where you can use their PCs — most often people use them for checking email or flight status — but since these devices are connected via USB or Firewire (more on that later), you can sit down, plug in your drive, and get to work.  These days especially, with the proliferation of netbooks, such drives are immensely useful.

In terms of connection, the most common is USB.  Generally, if you get one with Firewire, you may wish to ensure that the drive also has a USB connection.  This is important as, in the hotel data center example above, many computers aren’t equiped with Firewire connections (and I haven’t seen a netbook yet that has one, though they may exist).

Why should you care about USB versus Firewire?  Speed!  The sustained data transfer rates between USB and Firewire can be substantial, as shown below.

• USB 2.0 — 480 Mb/s maximum burst transfer rate, with an average sustained data transfer of 10-30 Mb/s
• Firewire 400 (aka 1394a) — 400 Mb/s sustained data transfer rate
• Firewire 800 (aka 1394b)  — 800 Mb/s sustained data transfer rate

That’s a huge difference!

My portable hard drive of choice is the Western Digital Passport line; for a 500 Gb drive, their USB My Passport Essential currently costs $150 while their USB/Firewire My Passport Studio can be purchased for $180.

Here’s an important point (with regards to the USB/Firewire drive mentioned above) and tip (with regards to the USB drive mentioned above) — you may wish to make sure the drives are formatted using the NTFS file system.  The USB/Firewire drive comes formatted for the Mac, so you’ll need to reformat anyways — just make sure you use the NTFS system.  On many USB only drives, they are formatted from the factory as FAT32 drives, so you’ll want to reformat them using NTFS.

What’s the difference between FAT32 and NTFS formatted drives?  A detailed description is beyond the scope of this post, but a few points are as follows.

• FAT32 has a 4 Gb file size limit, so you’d be unable to store any files greater than that size on a FAT32 drive
• NTFS has greater security features
• NTFS is more space efficient (due to it’s cluster size)
• NTFS has greater reliability

Here are a couple of articles talking about FAT32 versus NTFS:

• NTFS.com
• The Elder Geek
• Microsoft