Windows XP and Mac OS-X put "stuff" on my card

There have been many recent threads about memory cards, but I haven't
seen any that mentioned this specific item.

Windows XP and Mac OS-X added files and directories to the memory card
in my camera. I use nether of those two operating systems on any of
my computers, so here is how it happened.

I was using my Oly C-4000 at a friend's house who uses Windows XP.
She wanted copies of the pictures I had just taken, so I removed the
128MB SM card from the camera and placed it in a card reader connected
via USB cable to her computer. She then selected the image files on
the card that she wanted and copied them to the hard drive.
Everything was done with My Computer in XP.

I'm not a Windows expert, but it looked like it was a standard copying
operation. No message appeared other than the usual animated sheet of
paper flying from the card reader to the HD. When that procedure was
finished, I removed the card from the reader and placed it back in the
camera.

I took more pictures afterward. The camera worked fine and the
previous images were still available to view in the camera. When I
got home and was transferring the new images to my own computer, I
noticed that there was now an additional directory and a few small
files that were not graphic images. Even though they did not seem to
affect the camera operation, I removed them on general principles.

A month later, I visited a different friend who has a new iMac running
OS-X. We did the same thing, copying selected files from my SM card
to his computer via an external USB card reader. I also tried leaving
the card in the camera and connecting the Oly USB cable from the
camera to his computer. In both cases, the card appeared properly as
a drive letter.

Afterward, everything worked just like it did in my previous
experience with Windows XP. When I returned home and read the card
with my own computer, there was similar additional stuff on it. I
again deleted it, leaving only the image files in the directory tree
that the C-4000 creates. BTW, I did not reformat the card, nor need
to. DOS has always been very reliable for editing files and
directories on camera cards. Also, as expected with non-camera files,
the added items could neither be viewed nor deleted with the camera.

When any type of file is added to a camera card, it reduces the space
available for camera images. But since the additional stuff totalled
only a few kB, that was not a problem. Also, when I examined the
mysterious file(s), it looked like some kind of database index, not an
executable or anything suspicious. I think I read somewhere that XP
has a "feature" which makes it easier to view, sort, or catalog
images. If so, I'm sure Microsoft copied it from Apple.

I might be considered overly fussy, but I don't want Bill Gates or
Steve Jobs putting "stuff" in my computer or camera, especially
without asking permission. In any case, I'm curious whether there is
an option that I could tell my friends about which turns off that
"feature".

Bruce

P.S. This might be the cause of some of the more mysterious or
"mystical" problems that other users are having. It also might be why
some people feel that routine reformatting does improve performance.