Strange behavior

[Fritz Wettstein <fwenospam@gmx.ch>]

I have the following Problem:

swe@LinuxPPC:~$ sudo mkdir /sda1
swe@LinuxPPC:~$ sudo chown swe /sda1
swe@LinuxPPC:~$ ls -la /sda1
total 8
drwxr-xr-x   2 swe  root 4096 Jan 11 16:19 .
drwxr-xr-x  37 root root 4096 Jan 11 16:19 ..
swe@LinuxPPC:~$ mount /dev/sda1 /sda1
mount: only root can do that
swe@LinuxPPC:~$ sudo mount /dev/sda1 /sda1
swe@LinuxPPC:~$ ls -la /sda1
total 4908
drwxr-xr-x  14 root root   16384 Jan  1  1970 .
drwxr-xr-x  37 root root    4096 Jan 11 16:19 ..
-rwxr-xr-x   1 root root    6148 Jan 10 13:56 .DS_Store
drwxr-xr-x   2 root root    2048 Nov 23 12:27 .Trash-swe
.
.
.
-rwxr-xr-x   1 root root     180 Jan 11 15:59 hints
.
.
.
swe@LinuxPPC:~$ sudo mount /dev/sda1 /sda1
swe@LinuxPPC:~$ sudo chown -R swe /sda1
chown: changing ownership of `/sda1': Operation not permitted
chown: changing ownership of `/sda1/.Trashes': Operation not permitted
chown: changing ownership of `/sda1/macintosh.pdf': Operation not permitted
.
.
.
chown: changing ownership of `/sda1/hints': Operation not permitted
.
.
.
swe@LinuxPPC:~$ cat >>/sda1/hints
bash: /sda1/hints: Permission denied
swe@LinuxPPC:~$ sudo cat >>/sda1/hints
bash: /sda1/hints: Permission denied
swe@LinuxPPC:~$ su -
Password:
LinuxPPC:~# cat >>/sda1/hints

The user swe has the same group as root (0).
What's going on here?

Fritz