Canon 20D - File Structure and CF question

[Paul_Canning]

OK, so when I plug my camera into the PC, I notice it there are several folders on the memory card.

Some are empty, with the higher numbered ones containing recent photos. Can anyone explain how the camera's file structure works? Am I safe to delete the folders to essentially "format" the card?

When I empty the photos on the camera, the folder still exist on the CF card...

 

[Wivelrod]

I always formatted the CF card to wipe it on my 20D, and still do on the 40D and 5D2.

 

[Gnomey]

The 20D has a limit of 100 photos per folder, after filling the first folder it will create another for the next lot. It is safe to delete the empty folders, the camera will recreate a new folder to use the next time you turn it on.