Use a USB drive for backup?

Infopackets Reader Walt H. asks:

" Is it possible to create an image [backup] of your hard drive to an external USB hard drive? If so, what limits are there in creating the image and restoring it?

I can't add another hard drive to my laptop, plus I thought a portable USB drive could allow me to image more than one computer. "

Side note: USB is short from for Universal Serial Bus. It's a small port usually located at the back of your computer and is pretty much the standard connection used for external computer peripherals today (such scanner, mouse, keyboard, printer, etc).

My Response:

The backup image file Walt is referring to is a disk image. And yes, the portable device will work on any computer which supports USB under Windows 98+ (USB isn't supported under Windows 95).

But what about using the USB drive under DOS?

It's is safe to say that the majority of disk imaging programs of today run primarily under DOS, with the exception of Acronis TrueImage which can also create an image while Windows is still loaded:

Acronis True Image 8.0 Review

So what happens if the imaging program runs under Windows, but Windows is inoperable and you want to restore an image on a USB device? The answer is that the disk imaging program (such as PowerQuest DriveImage, or Symantec Ghost) would have to run from DOS.

And if the USB drive isn't compatible with DOS, that means that the backup file will not be accessible.

DOS is a legacy Operating System and there is limited support for peripherals such as a USB device. All USB devices are not the same; some may work under DOS, while others may not. This also holds true for the imaging software which also runs under DOS: some USB drives may work, and some may not.

The only sure-fire way of knowing is to try the scenario on your own.