Suddenly can't write to USB flash drive

[GottaBuild]

I am running Knoppix with no hard drive, just a USB flash drive mounted as sda1. The drive is only 1/4 full. I can see from using Konqueror to browse files and also from the command line that all files have rwxrwxrwx permissions. I am trying to write to the USB drive but can't. If I use KEdit I get the message:

"The document could not be saved, as it was not possible to write to file:///mnt/sda1/asd.
Check that you have write access to this file or that enough disk space is available."

If I try to export bookmarks from Firefox I get not error message but the file is never written to the disk. I believe the problem started when I removed the USB drive and then replaced it during normal operations. After plugging the drive back in, I remounted it, and now I can read files fine, just can't write. I tried to unmount sda1 and then mount it again, but when I enter the command "umount /mnt/sda1" I get this message: "umount: /mnt/sda1: device is busy". Perhaps this is a clue.

Any ideas on how I can save all the work I have in memory before rebooting? Thanks!

[Harry Kuhman]

answer #6