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USB 2.0 Support in Windows XP: High Speed at Last
Published: August 5, 2002
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The Universal Serial Bus (USB) technology lets you easily connect peripheral devices such as digital cameras, scanners, or mice to your computer. USB is designed to work with all sorts of devices, and to support hot plugging and Plug and Play. So you can connect your camera, for example, to the PC and start downloading pictures, without configuring software or rebooting.
The original USB standard offered great advantages over earlier connection technologies and its popularity spread. However, the version of USB we use most today, version 1.1, was designed with a maximum data transfer rate of 12 megabits per second (Mbps). That's speedy enough for a keyboard, mouse, and maybe a CD-ROM drive, but it's peanuts when you're working with digital video or high-speed external hard drives.
Higher speed technologies were starting to gain on USB's popularity. The most common technology for transferring digital video to a home PC has been the Institute of Electrical and Electronics Engineers (IEEE) 1394 standard. Also known as FireWire, it beats the socks off USB 1.1 with a 400 Mbps data transfer rate, which is why most digital video cameras come with IEEE 1394 (FireWire) ports, not USB.
But now there's a new version of USB, USB 2.0, with a hefty 480 Mbps data transfer rate, making it faster than IEEE 1394 (FireWire), and earning it the nickname Hi-Speed USB. USB devices have always operated at either 12 Mbps (for full-speed devices) or a mere 1.5 Mbps (for devices with lower bandwidth needs). USB 2.0 lets you use more of those devices at once and also adds a new speed, which can use the entire 480 Mbps bandwidth that USB 2.0 provides for Hi-Speed devices. Such high speeds are critical in bandwidth-hungry applications like mass storage devices, although not all devices are capable of running at 480 Mbps. For example, your USB 2.0 mouse is still a low speed device and is probably running at only 1 Mbps, but your USB 2.0 Hi-Speed CD-RW can take advantage of the new USB 2.0 high speeds and burn CDs much faster.
Compatibility with USB 1.1
Microsoft and the others who created USB 2.0 didn't leave USB 1.1 folks in the dust. USB 2.0 is fully compatible with USB 1.1 devices. The older devices work with the new bus, and vice versa.
However, keep in mind that you can't connect a Hi-Speed USB device to a USB 1.1 controller and expect it to run faster. Your computer will only run as fast as the slowest link in the chain.
In other words, all the USB 2.0 hubs in the world won't help my old laptop computer, which has built-in USB 1.1 controllers. I'll have to add a PC Card-based USB 2.0 controller, or buy a new laptop that has a USB 2.0 controller built in. Hi-Speed USB 2.0 devices will work fine when they're plugged into an older USB 1.1 controller—but they'll run at only 12 Mbps, instead of the full 480 Mbps.
The Hi Speed USB backward-compatibility means that I can start looking for new USB 2.0 devices now, even though not all of my computers have USB 2.0 capability. If you've been frequenting your local computer store, you've probably noticed USB 2.0 devices already. A number of manufacturers have USB 2.0 PCI controller cards for desktop PCs available for less than $50. PC cards for laptop USB 2.0 support are available for less than $80. And high-quality USB 2.0-compatible cables have been around for months. USB 2.0 shouldn't require you to buy new USB cables, unless you have really cheap cables that don't work well with USB 1.1, either. Certified USB 2.0 cables are available, but they're usually just high-quality USB 1.1 cables.
I can't tell you how often I've had to wait while my MP3 player downloaded a few megabytes of information at slow USB 1.1 speeds, and how much nicer it will be to use a fast USB 2.0 connection instead. I'm just waiting for a USB 2.0-compliant MP3 player to hit the market, because while my USB 1.1 player will run just fine on my new USB 2.0 hub, it can't run any faster.
USB 2.0 Device Driver Support
Some manufacturers now sell new PCs and laptops with support for USB 2.0 built in. If you want to add USB 2.0 to your computer, you must buy a USB 2.0 controller card and install it. For a desktop computer, this involves opening the case for access to your computer's PCI slots. For a laptop, you plug in the card whenever you want to connect a new Hi-Speed USB device. Most manufacturers provide installation and setup guides. Here is an example from Adaptec.
The Windows Catalog lists several USB 2.0 controller cards that are compatible with Windows XP.
Drivers for USB 2.0 devices in Windows XP became available on Windows Update in January. Windows XP Home Edition and Windows XP Professional are both fully USB 2.0-compliant with the correct drivers. Again, check the Windows Catalog before you buy a new USB 2.0 device to make sure it's compatible with Windows XP.
After you've installed your new USB 2.0 controller and devices, connect to the Internet and open Windows Update. Make sure that your new hardware is plugged in and operating (at least at low speed). If Windows XP recognizes your USB 2.0 hardware, it will offer you the chance to download the new USB 2.0 drivers. You can also manually download the driver by following the steps in Universal Serial Bus 2.0 Support in Windows XP.
USB 2.0 driver on Windows Update
Troubleshooting USB 2.0 Device Drivers
The Microsoft USB 2.0 driver may not be listed as an available update if third-party USB 2.0 drivers are installed on your computer. You may have to remove the third-party USB 2.0 drivers, and then install the Microsoft USB 2.0 driver from the Windows Update Web site.
The USB 2.0 drivers for Windows XP that are on Windows Update today only recognize devices using the NEC USB 2.0 EHCI controller chipset. The industry specification for Hi-Speed USB is called the Enhanced Host Controller Interface (EHCI ). That doesn't mean you have to buy an NEC-brand controller. The NEC chipset is fairly ubiquitous in the USB 2.0 world. That chipset is also the first one to be certified by the independent USB 2.0 testing body. Although the USB 2.0 drivers currently available on Windows Update only support the NEC controller, there should be an update soon that supports all EHCI-compliant controllers.
If you've made sure that everything on your computer is USB 2.0-compliant, and you're still getting low-speed results, you may not have the right drivers. Symptoms in Windows XP can include error messages such as “The Generic USB Hub is a HI-SPEED USB device and will function at reduced speed when plugged into a non-HI-SPEED port,” or “A HI-SPEED USB device is plugged into a non-HI-SPEED USB hub.” You may also see your high-speed controller card tagged with a yellow exclamation icon in Device Manager. The problem is that although you have a Hi-Speed hub or controller, Windows XP doesn't recognize it. (See the Knowledge Base article, Universal Serial Bus 2.0 Support in Windows XP for more detailed information).
Windows XP USB Driver Architecture
The original USB 1.1 driver in Windows XP was designed with USB 2.0 in mind, so adding USB 2.0 support didn't quite require Microsoft to start from scratch. The marvel of the USB architecture in Windows XP occurs at the Host Controller Driver: It is supported by mini-ports that each implements a specific type of USB support.
For those with knowledge of driver development, it's interesting to know that Windows XP originally included two mini-ports, Usbuhci.sys and Usbohci.sys. Adding USB 2.0 support requires a new mini-port, Usbehci.sys. USB 2.0 support updates Usbport.sys, Usbhub.sys, and other key USB support drivers. Windows XP also uses a host controller-specific coinstaller, Hccoin.dll, which provides for interaction between the USB 2.0 controller and companion host controllers. Windows 2000 wasn't so lucky: Microsoft built an entire new USB 2.0 device driver stack that operates in parallel with the old USB stack.
If you have a computer running Windows 98, you can get USB 2.0 drivers from third-party vendors like Adaptec, NEC, and Orange Micro. The vendors all sell USB 2.0 controllers, including drivers, which are compatible with Windows 98.
You can learn more about the hardware details behind USB 2.0 support in Windows XP in the USB 2.0 and Windows paper on the Windows Platform Development site.
Shopping for USB 2.0 Devices
Whenever you go shopping for a new Hi-Speed USB device, look for the official Hi-Speed USB logo, which can be seen on the USB Web site. (More details on USB 2.0 and other USB news can also be found there). Devices that don't display this logo aren't certified as compatible with the USB 2.0 specification, and may not work properly, or may cause problems with your other USB devices. Of course, you should also keep an eye out for the “Designed for Windows XP” logo to ensure that the device will be compatible with Windows XP.
Future Developments in USB 2.0
The USB 2.0 specification also describes a “mini USB-B” connector, which is a miniaturized connector port. This tiny port will make high-speed USB more acceptable to manufacturers of consumer electronics devices like MP3 players, digital cameras, digital camcorders, and other handheld devices without a lot of real estate for large plugs. Today, manufacturers of smaller devices rely on proprietary cables, so the mini USB-B connector should bring some standardization to the marketplace.
USB 2.0: Should You Care?
USB 2.0 makes attaching USB hard drives to your computer infinitely more rewarding. I have a USB 1.1-compatible hard drive and it's no treat waiting for data to crawl to and from that thing. So getting a USB 2.0 hard drive is high on my list of things to do.
Other USB 2.0 devices available now include cameras, scanners, hubs, IDE adapters that let you connect a regular hard drive to USB, and more. Expect to see printers and camcorders hitting the market in the next few months.
The bottom line? The original USB helped fully realize the promise of hot plugging and Plug and Play peripheral devices. USB 2.0 expands on that promise by offering high-speed data transfer. Windows XP is right there with USB 2.0 support to help make it all possible.
Expert Zone Columnist Don Jones is a writer, speaker, and a founding partner of BrainCore.Net. He is the author of a rapidly growing collection of computer books, including the Windows Server 2003 Weekend Crash Course. Don lives full-time in a 40-foot, fully computerized RV, traveling across the United States and is happiest when he has a new technology to play with. Don's favorite computer game is Pinball Arcade. You can reach Don at firstname.lastname@example.org.