A Limitation with USB Flash Drives

[jaugustine]

Hi,

If you use a USB flash drive ("thumb drive") and you can't copy
another file to that drive, with an error message such as "access denied"
or "unable to create...", it is possible you may have used up the space
available, used for the names of files and folders/directories in the "root"
folder/directory.

To "fix" this, move (copy then delete) some files to the hard drive.
Then create a folder(s) at the root directory. Afterwards, copy files into
a folder.

The "root" directory has a limit to the number of entries (filenames and
folder names) it can accommodate.

John

 

[Andrew Rossmann]

If you use a USB flash drive ("thumb drive") and you can't copy
another file to that drive, with an error message such as "access denied"
or "unable to create...", it is possible you may have used up the space
available, used for the names of files and folders/directories in the "root"
folder/directory.

To "fix" this, move (copy then delete) some files to the hard drive.
Then create a folder(s) at the root directory. Afterwards, copy files into
a folder.

The "root" directory has a limit to the number of entries (filenames and
folder names) it can accommodate.

This is a limitation of the FAT16 format, which has a fixed 512
directory entries available. It's worse with anything that doesn't fit
the old 8.3 ALL UPPERCASE filename format, as those use mulitple
directory entry slots.

If it's formatted using FAT32, then there is no limit, as the root
directory is treated like a subdirectory and can expand as needed. The
drawback with any FAT format is that any individual file is limited to
4G.

You can use NTFS with a Windows computer, which removes all the limits.

The drawback with NTFS is that few devices other than a Windows computer
will read it. Some non-computer devices may not support FAT32, either.

Some info:
http://support.microsoft.com/kb/310525/en-us
http://support.microsoft.com/kb/100108/EN-US/
http://support.microsoft.com/kb/120138
http://support.microsoft.com/kb/154997/EN-US/

 

[Tim Slattery]

If it's formatted using FAT32, then there is no limit, as the root
directory is treated like a subdirectory and can expand as needed.

It expands until it hits the limit of 65,536 entries. Each file or
subdirectory will take from two to thirteen entries, depending on the
length of its name. So you can still fill up the root directory while
there's lots of space left on the drive, but you have to work harder
at it then you did under FAT16.

The rawback with any FAT format is that any individual file is limited to
4G.

That's true.

You can use NTFS with a Windows computer, which removes all the limits.

Umm...not *any* windows computer, any NT-based Windows computer. That
excludes Win3.x, Win95, Win98, WinME. Not that many folks still use
those anyway.

The drawback with NTFS is that few devices other than a Windows computer
will read it.

I believe Linux machines can deal with it, I'm not sure about Macs.

Some non-computer devices may not support FAT32, either.

Definitely.