The Faulty UFD: Sometimes A New Problem Requires An Old SolutionThe Faulty UFD: Sometimes A New Problem Requires An Old Solution

"UFD" is the official TLA for the ubiquitous "USB flash drive" or thumb drive. I didn't know that until I looked it up. But I do know how to fix one when it dies, because my hair is grayer than yours. I remember how to use the DOS FORMAT command.Back in the days when "mobile storage" meant 16-Kbyte 5 1/4-inch floppy disks, every one had to be formatted before it could be used. Floppies have pretty much become dinosaur storage, and flash drives and flash cards, quick little mammals, have taken over. But deep in their DNA they still share FORMAT with their extinct forebearers. So when a shiny new 1-Gbyte flash drive went into a death spiral in a front-panel USB port of my PC yesterday. I knew just what to do to fix it.

Check that. I almost knew what to do. Along with the blessing of being old enough to remember the FORMAT command comes the inevitable curse of being old enough to forget the particulars, like the command switch for file system type.

Fortunately, operating systems have DNA, too, and every copy of Windows still carries the genes -- and help files -- for all those DOS commands you haven't used for 10 years or more.

The first thing you have to remember, of course, is how to get to the DOS prompt: click Start, click Run, and type CMD into the box. Then if you've forgotten how to use the file system switch like I had, at the ">" prompt type HELP FORMAT.

Once you've gotten over the amazing feeling that typing text commands is as retro as chopping firewood to heat your log cabin, you'll discover that the command you need is something like

FORMAT G: /FS:FAT

The "G:" is, of course, the drive letter for your ailing flash drive. That command switch (the forward slash followed by FS for "file system") is the second thing you need to know. Most flash-memory devices use plain old FAT with support for long file names, according to the Wikipedia's very informative article on USB mass storage, but you can format a flash drive using any file system you want -- NTFS for Windows or HFS Plus for Macs, for example. Windows Vista will even format a flash drive with UDF, the Universal Disk Format used by optical disks -- not that you'd ever want to do it. FAT goes good with pretty much everything, and using any anything else just makes your flash drive a little less portable.

The same treatment works for flash cards, too -- the SD card in your digital camera, for instance. If it goes haywire and you can connect it to a PC, you can reformat it. Of course, a FORMAT wipes the flash device clean. All your data is lost. Generally with UDFs this isn't a serious problem. The data exists somewhere else, because that's how it got onto the flash drive. With flash cards that contain data you might want to save (how many month's worth of photographs are you carrying around, not backed up anywhere else, on your camera?) you can try another primeval DOS command: CHKDSK, which looks for and repairs errors in the file-allocation tables that give FAT its name.

If you're so young you've never seen a DOS prompt you ought to take a look at it. There's a whole computing museum buried inside Windows. And you don't have to thank me -- but the next time you see me on the bus if you'd get up and give me your seat I'd appreciate it.