I had ignored the special Y cables that came with each of the two drives.
Al Fasoldt's reviews and commentaries, continuously available online since 1983


Beware of overloading USB

Feb. 20, 2011

By Al Fasoldt
Copyright © 2011, Al Fasoldt
Copyright © 2011, The Post-Standard

   Three cheers for USB.
   Er, make that two and a half cheers. I battled a USB problem that stumped me for months. Despite my wife's belief that I know everything there is to know about computers, I was lost. I finally gave up and had to take the last resort.
   I looked in the manual. In this case, the "manual" was a bunch of support sites on the web. It didn't take long for me to shout "Eureka!"
   Here's what happened:
   Running low on extra storage space , I bought some new USB external hard drives. I got two tiny ones each the size of a billfold. They're the kind that get their power from the USB connection. This helps keep them cheap. (One of them was only $19.)
   Naturally, I realized both needed to be plugged into a powered USB hub. I rearranged some of the USB connections on my computer desk so that both of the little drives could be plugged into my newest powered hub. It's got two quick-change USB ports on the top and five more-or-less permanent USB ports on the back. The other ports on that hub were filled with connections to powered drives. I figured that was OK.
   Bad assumption. Within a few weeks the tiny drives started failing. Every hour or so they would disappear from the computer. I couldn't save files. Files that were on the drive often got messed up.
   Was it gamma rays? (I've read that gamma rays actually can disrupt circuits.) Or the cold weather? (Sometimes changing temperatures can give a hard drive a bad hair day.) Or Just a bad hub?
   I switched to an older hub. Same problem.
   The difficulty, as I learned from my research on the web, was that I had ignored the special Y cables that came with each of the two drives. These Y cables have one USB connector on the drive end and two on the other end. You're supposed to plug each Y-end cable into a separate port on the hub, or into separate USB ports your computer if you don't have a hub.
   Bah. Who'd want to do that?
   Me. I found out that the extra connector has a very important function. It doubles the electric current that goes to a USB-powered drive. Without it, the drive doesn't get enough current and stops working right. This means any files that are being accessed on the drive when it fails are turned into chop suey. You end up with a non-working drive that's starved of power and corrupt of files, as Will Shakespeare might say.
   So here's what I learned. If your new USB drive comes with a Y-connector, use it. And buy an extra powered hub if you have more than two extra drives of any kind (external hard drives or external DVD burners and so on). Otherwise an overtaxed hub might fail.
   Don't be like me. And don't tell my wife.