Over the last year, external hard drives have evolved significantly -- and the change doesn't only involve increased capacity. Driven by the realization (finally) that Macs and PCs can typically handle the same data types (music, pictures, and movies) and that building separate drives for the two platforms is not financially advantageous, vendors are standardizing their drives on the USB 2.0, FireWire 400 (1394a), and FireWire 800 (1394b) interfaces.
Three of the latest drives that represent this trend are the Iomega Triple Interface Professional Silver Series Desktop Hard Drive, the Maxtor OneTouch III, Turbo Edition, and Western Digital's MyBook Pro Edition II. While these units don't quite represent every variety of external drive, they do characterize the genre quite well.
For example, the 750-Gbyte Iomega, while smallest of the three in both size and capacity, is no slouch -- it's a single-drive unit in a world where 500 Gbytes in a box was pushing both heat and capacity boundaries last year. The Maxtor and Western Digital units offer, respectively, dual 750-Gbyte drives for a 1.5-terabyte capacity, and dual 500-Gbyte drives for a 1-terabyte capacity; both are enclosed in RAID boxes. All of the drives are intelligent enough to power down when not in use -- a good thing, since prolonged usage will make them warm to the touch.
Interestingly, the vendors of all these of these units appear to have settled on EMC Retrospect Express as their choice for backup software. It’s a robust package that offers automated and immediate backup procedures and can create a disaster-recovery strategy.
While the software's primary advantage over the competition is that it comes free with the hardware, you’ll find that while Retrospect Express can be a bit obtuse in spots (read the documentation!), it works, it works well, and it works quickly. Finding all three of those features in one software package is not usual.
A Choice Of Interface
As noted, each of the tested hard drives supports a trio of interfaces:
- FireWire 800 (1394b), offering up to 800 Mbyte/sec data transfer rates
- FireWire 400 (1394a), offering up to 400 Mbyte/sec data transfer rates
- USB 2.0, offering up to 480 Mbyte/sec data transfer rates
While both the USB and FireWire 400 interfaces are common to both Mac and PC platforms, FireWire 800 is found more often on a Mac. PCI cards with FireWire 800 are available for Windows environments -- they’re priced in the range of $30 to $70, and while adding more money on top of the drive purchase may seem unattractive, there is a possible benefit.
Ad hoc testing on the Iomega drive using Retrospect Express showed a 1,566.7 Mbyte/min transfer rate using USB 2.0, 1,847.1 Mbyte/min with Firewire 400, and 2,487.5 Mbyte/min using Firewire 800. That’s a 900+ Mbyte/min jump over USB 2.0 and a 600+ Mbyte/min jump over Firewire 400. While there can be variations in performance based on the actual implementation of any interface, faster computer operations are always better than slower ones when calculating what your time is worth.
The two external units that support RAID, Maxtor and Western Digital, also both support RAID 0 (disk striping), and RAID 1 (disk mirroring). Under RAID 0, the two drives are used as one logical storage area with a capacity equal to the sum of the two drives' storage space. (Two 500-Gbyte drives would be combined to become 1 terabyte, two 750-Gbyte drives would become 1.5 terabyte, etc.) Under the second RAID arrangement, the total capacity is equal to that of just one drive while the additional drive is used to backup (mirror) the contents of the first.
RAID 0 is typically used to pick up a slight speed increase during data transfers while RAID 1 is a security measure and may actually slow performance slightly. RAID 0 provides no data security should one drive fail. If not backed up elsewhere, your data is lost. RAID 1 will let you rebuild the contents of one drive from the other should a single drive failure occur. (Naturally, if both drives fail you’re out of luck. Nothing is perfect.)
And Then There's NAS
One problem with attaching a USB or FireWire external hard drive to your PC is that any time anyone on your network wants to access a file from it they are, effectively, going through your computer to do so. That doesn't only compromise your system's security, it's going to slow down your PC -- a lot. One of the better solutions for the networked user is to move the attached storage onto the network itself via network attached storage (NAS).
While NAS devices have almost a two-decade track record in enterprise systems, their popularity on the desktop is only a few years old. I tested one of the latest desktop NAS drives to hit the market, the Iomega StorCenter NAS 150D, to see how it compared with the more common USB and FireWire drives.
Whatever type of drive you choose, keep in mind that hard disk prices tend to be fluid -- and that prices typically shift in a downward direction. So keep looking around for bargains.