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USB—IT'S NOT JUST A BUS, IT'S ANADVENTURE

by Tom Cantrell

Start ı Nearvana ı Waiting for Baudot ı Not So Fast ı VolksPort ı Going Mobile ı Sources and PDF

WAITING FOR BAUDOT

On the desktop, all the excitement centers around the new USB 2.0, with its promise of both backward compatibility with existing 1.5- and 12-Mbps USB 1.1 sockets and a new turbocharged 480-Mbps High-Speed mode.

USB is already finding favor in devices such as mass storage and scanners that really call for more bandwidth than 1.1 can deliver. Most users have no choice but to accept the compromise in light of the lame alternatives (i.e., serial port, parallel port, or plug-in card).

The emergence of 2.0 will make USB a proper, not just pragmatic, choice for these higher bandwidth devices. The only question is how soon 2.0 will ramp up. About a year ago, I covered the then emerging 2.0 story ("Being Merry With USB," Circuit Cellar Online, January 2001). At the time, I wrote that for USB 2.0, as with the original version, the "full-fledged takeoff will only occur after 2.0 is built in to PCs and Windows, something which apparently wonıt happen for a year or two."

Iıll stick by that, noting that at this moment 2.0 is still somewhat of a bleeding-edge proposition. Chips are shipping, but motherboards with built-in 2.0 ports are still in the labs and havenıt hit the street yet. Windows XP, which Iım told has some measure of 2.0 support, has just been rolled out and wonıt represent a significant percentage of the PC-installed base for some time.

It might be tempting to think the beachhead established by the original version of USB would accelerate the takeover of 2.0, but Iım not sure thatıs the case. The fact is that a 2.0 setup starts with a 2.0-capable host PC and dead-ends without it. Other than finely parsed examples of contrived configurations, as far as I can see, thereıs little to be gained by adding a 2.0 peripheral to a 1.1 host.

That means for the vast legions of current 1.1 PCs running pre-XP Windows, the only option is going under the hood with a third-party plug-in 2.0 card and driver (see Photo 3).

Photo 3ıFor now, getting on the USB 2.0 bandwagon requires adding a host adapter such as the USB2connect 5100 from Adaptec.

Thatıs neither an extraordinarily scary nor expensive proposition, but itıs hard to argue that itıs a likely course for more than a few percent of the installed base. With a dearth of 2.0 hosts, peripheral suppliers will have little incentive to accelerate their designs to the new standard.

Iıd say weıre looking at least late 2002 before 2.0 starts to become standard equipment. But, thanks to the compelling speed boost, thereıs no doubt it eventually will.

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