When you delete everything from a flash drive and reformat it, you would think it should ‘display’ as completely empty when checked, but that may not always be the case. With that in mind, today’s SuperUser Q&A post has the answer to a confused reader’s question.
Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.
Photo courtesy of Adikos (Flickr).
The Question
SuperUser reader Andrew wants to know how there can be used space on an empty and freshly formatted flash drive:
How can there be used space on an empty and freshly formatted flash drive?
After reformatting the flash drive, Windows tells me that it is not completely empty. If I right-click on the flash drive in Windows Explorer and select Properties, Windows gives me this information:
Why is this the case even though I just formatted the flash drive? Is this to be expected or are there some files still lingering on the flash drive? When I open the flash drive in Windows Explorer, no folders or files appear even though my system’s settings are configured to show hidden items. I find it worrisome that there is a total of 91.7 MB somehow being used on this supposedly “empty” flash drive.
The Answer
SuperUser contributor David Schwartz has the answer for us:
Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.
The largest one is probably the cluster allocation bitmap (“$Bitmap”) that keeps track of the space that is used and the space that is free. This is pre-allocated when the file system is created.
