Stick a Hard Drive in Your Pocket How to Choose and Connect the Latest USB 2.0 and IEEE-1394(FireWire) External Drives

Stick a Hard Drive in Your Pocket
How to Choose and Connect the Latest USB 2.0 and IEEE-1394(FireWire) External Drives

If you're out of drive bays inside your computer or want to move gigabytes of storage between computers, you're no longer out of luck. Today's new breed of high-capacity, high-performance hard drives based on the new USB 2.0 and existing IEEE-1394a standards enable you to hot-swap drives between systems and carry a huge amount of storage in your pocket.

There are several factors to consider in your search for fast portable hard disk storage, including:

• Capacity
• Interface type
• Operating system compatibility
• Shock Resistance
• Host adapter requirements
• Upgrading hubs and cables

This article shows you how to avoid potential pitfalls on your way to the best portable hard disk storage for your needs.

Capacity

Today's newest IDE/ATA desktop hard drives have capacities of 120GB, and the 127GB barrier of the ATA-5 standard is looming over current systems. Depending upon the pocket-sized portable hard drive you choose, you can disregard the 127GB barrier, or select a model with a more modest capacity that still rivals recent entries in the "big desktop drive" sweepstakes, as you can see in this table of portable hard drive capacities.

Portable Hard Drive Capacities from Major Vendors

As you can see, you can choose any capacity you like, provided you have the right interface. Since the interface (USB, FireWire, etc.) handles communication with the drive, rather than the system BIOS, you can install and use drives which are larger than the IDE drives your system BIOS can work with.

Potential pitfall: buying a drive that's too small means you'll be back for another relatively expensive drive in the future.

Best bet: buy the largest drive you can afford that also has the performance, interface type, and other features you want.

Interface Types and Drive Speed

Until recently, the largest and fastest portable drives have used the IEEE-1394a (FireWire/iLink) interface, which is many times faster than USB 1.x. However, with the advent of USB 2.0 (also known as Hi-Speed USB), several vendors now support this faster version of USB.

Here's how the three interface types stack up in speed:

From the standpoint of interface speed, USB 2.0 is the new speed champion, edging out IEEE-1394a/FireWire. However, note that most of the drives you are connecting have a slower transfer speed than what either interface is capable of supporting, meaning that the drive specifications become more important than the interface it is connected to. For example, LaCie's PocketDrive series, which support both IEEE-1394a and USB 2.0 interfaces, features a 16MB/sec transfer rate when the USB 2.0 interface is used, but its IEEE-1394a interface features a maximum write transfer rate of 25MB/sec and read transfer rate of 35MB/sec. Drives that feature just one port type or the other generally boast faster data-transfer rates. For example, Fantom's line of 5400 rpm USB 2.0 drives have a maximum data transfer rate of 60MB/sec (equal to the peak USB 2.0 rate of 480Mps), while its line of IEEE-1394a/FireWire drives support a 50MB/sec data transfer rate (equal to the peak IEEE-1394a rate of 400Mbps).

Drive rotational speeds also vary a great deal, with some vendors offering drives as fast as 7200 rpm, while others continue to use 5400 rpm or slower drives. While greater rotational speed doesn't usually affect a drive's rated data transfer rate (the interface type is the major limiting factor), a drive that spins faster can help you locate data faster.

Potential pitfalls: Buying a drive that won't work with your operating system or interface type you prefer; buying a drive which isn't as fast as you need.

Best bet: Choose a drive based on the operating system and interface type you prefer; choose combo IEEE-1394a and USB 2.0 drives only if you already have both interface types on your systems.

Operating System Compatibility

In most cases, if you use Windows 98, Windows Me, Windows 2000 or recent versions of MacOS, you will be able to swap a USB 1.x or IEEE-1394a drive back and forth between operating systems. However, if you want cross-platform compatibility, be sure to check the specifications for your drive first. Some vendors, such as Buslink, for example, sell separate PC and Mac versions of some drives.

While some vendors have added Windows XP-specific drivers to the installation CD or their support Web sites, others don't yet offer Windows XP drivers. If you use Windows XP, be sure to verify that your preferred drive has Windows XP drivers before you make your purchase.

Potential pitfall: No Windows XP support or separate Windows/MacOS models.

Best bet: Choose a drive which already offers Windows XP drivers; select drives which can work with both Windows PCs and MacOS-based systems.

Shock Resistance

While all IEEE-1394a and USB drives are designed to be portable to a certain extent, thanks to their external interface and support for hot-swapping, there's a big difference between swapping drives in a typical home or office environment and popping a drive into your pocket for a long cross-country trip. If you need to transport a standard USB or IEEE-1394a drive between locations, plan on using a securely padded case for protection, or buy the shock-resistant models made by LaCie or BusLink. While these models don't feature the over 100GB storage options of conventional external drives, their internal and external design helps prevent drive and data damage during transport.

Potential pitfall: Buying a drive that's not rugged enough for travel; buying a drive that's not large enough for high-capacity storage.

Best bet: Buy a drive suitable for your preferred environment (single location or travel) that's as large as you can afford.

Host Adapters

While USB 2.0 and IEEE-1394a interfaces offer huge speed advantages over the slower USB 1.1 interfaces, they share a common limitation: most systems don't have these faster interfaces built-in.

If you don't have either interface in your system, you will need to decide how to add the interface. You can, of course, install a wide variety of IEEE-1394a or USB 2.0 interface cards from many vendors into an open PCI slot on a desktop computer, or install a CardBus PC Card into a compatible notebook computer slot. However, before you start shopping for an interface card, you should decide which interface best suits your needs.

Until the advent of USB 2.0-compatible drives and devices, IEEE-1394a was the way to go as far as hot-swap removable drives in terms of speed. Even though most USB 2.0 drives are a bit faster than IEEE-1394a drives, you may still want to use the IEEE-1394a interface if you also have a DV camcorder or plan to edit digital video. If you're short on open PCI slots, consider using a high-end sound card that also includes an IEEE-1394a port, such as the Creative Labs Sound Blaster Audigy. The Audigy series features an IEEE-1394a jack, enabling you to attach external hard drives and other IEEE-1394a devices without installing a separate host adapter. For best results with the Sound Blaster Audigy, I recommend that you verify that the external drive you want to use is on the SB1394 Certified or SB1394 Compatible list of products at http://www.soundblaster.com/sb1394/. Adaptec, Maxtor, Orange Micro, and SIIG are some of the major vendors which can supply you with a separate IEEE-1394a card if you prefer.

If you already have a wide variety of USB 1.x-compatible devices, or want the even greater speed of USB 2.0 drives, opt for a USB 2.0 interface card from vendors such as Adaptec, Belkin, Maxtor, Orange Micro, or SIIG. USB 2.0 interfaces handle multiple USB 1.x devices better than a USB 1.1 interface can. If you're in the market for a new computer or motherboard upgrade, look for USB 2.0-compatible motherboards and systems now coming on the market, such as MicroStar International's K7T266 Pro2-RU motherboard, Giga-Byte's GA-7DXR+, and the Gateway 700XL. Most of these motherboards use a separate USB 2.0 chip made by NEC. Intel's ICH-4 South Bridge-equivalent chip integrating USB 2.0 is due out in April 2002 for use with many of its existing and forthcoming memory controller hub (North Bridge-equivalent) chips, while VIA Technologies offers its own VT-6202 host controller for use on either PCI cards or as a separate motherboard chip.

If you prefer a built-in IEEE-1394a interface, most recent Sony VAIO notebook computers have it, as well as some Compaq, Gateway, and Dell notebook and desktop computers.

If you're otherwise happy with your current system but want to get both USB 2.0 and IEEE-1394a interfaces in a single PCI slot, you can get combo USB 2.0 and IEEE-1394a cards from vendors such as Orange Micro, Adaptec, and SIIG. Notebook computers users with CardBus slots will need to opt for separate IEEE-1394a or USB 2.0 CardBus PC Cards.

Potential pitfall: Running out of PCI slots if you need both IEEE-1394a and USB 2.0 ports.

Best bet: Use a combo IEEE-1394a/USB 2.0 card or get a new motherboard or system with USB 2.0 or IEEE-1394a built-in to save a slot.

Hubs and Cables

If you decide to make USB 2.0 your preferred interface for portable hard drives, don't forget to upgrade your hubs; a USB 1.x-compatible hub will drop the 480Mbps performance of USB 2.0 down to a 12Mbps crawl.

While some vendors claim that standard USB cables should be able to support either 12Mbps or 480Mbps speed, older cables could be a weak link in your USB daisy-chain. To avoid problems, use the cables included with USB 2.0 drives, or select certified USB 2.0 cables if you need longer cables.

Potential pitfall: USB 1.x-compliant hubs and cables slow down USB 2.0 peripherals.

Best bet: Upgrade hubs and cables to USB 2.0 standard.

Conclusion

USB 2.0 has arrived, and the combination of high performance with the widest compatibility and the largest number of available peripherals clearly makes it the best choice for most PC users. While the typical system will need a host adapter to be ready for today's IEEE-1394a or USB 2.0 portable hard drives, the investment is worth it if you have large amounts of data to move from system to system. If your desktop computer is out of drive bays or if you rely on notebook computers, these drives can save you from expensive hardware upgrades.

For More Information

Drive Vendors

Host Adapter Vendors

Motherboard, Chipset and System Vendors

Interface Technologies

Copyright©2002 Pearson Education. All rights reserved.