Spurious "Disk Full" message from USB drive
I have a Lexar Jump Drive with 512MB. It
shows 128MB used but will not allow any
more files to be added; it displays the
message "disk full." How can I get this drive to
accept more data?
Answer : This exact problem cropped up when Microsoft first
introduced long filenames. The root directory of a floppy disk has precisely
224 slots to hold directory entries. Before long filenames, that was enough
for 224 files, and very few people ran into that limit. But each long
filename takes from two to twenty directory entries, depending on its length. Some people have been getting
"disk full" errors even when a floppy disk was only
half full. USB drives are typically formatted using
the same FAT16 file system that's used for floppy
disks, and they have the same problem. The root
directory has a fixed size, and once it has been filled
you can't add any more files. That fixed size may
vary; in a sample I tested the limit was 510 entries.
Fortunately, there's a simple solution: Store your
files in subfolders. The number of directory entries
in a subfolder is variable, increasing automatically as
needed. You can't create a subfolder in a root directory that's already full, so move some files temporarily off the USB drive. Create a new folder on the USB
drive and move all or most of the files into it. Once
you've started doing this, you may choose to create
other subfolders and organize your files by category.
The main thing is to stop dropping everything into
the root directory. Now you'll be able to take advantage of the full capacity of your USB drive.