[ydl-gen] About permissions, etc.

[Charles Trois]

Hello!

I am a bit confused about some matters related to permissions.
Here is a part of my fstab file:

Sirrah ~ # cat /etc/fstab
...
/dev/hda9   /mnt/giga       hfs       defaults,umask=0          0 0
/dev/hda10  /mnt/Sigma      hfsplus   defaults                  0 0
/dev/hda11  /mnt/SigmaX     hfsplus   defaults                  0 0
...

and here are the contents of /mnt:

Sirrah ~ # ls -l /mnt
total 8
drwxr-xr-x 1 root root   28 Dec 21 17:00 Sigma
drwxrwxr-t 1 root cdrw   38 Jan 21 09:52 SigmaX
drwx------ 2 root root 4096 Aug 11 01:49 cdrom
drwx------ 2 root root 4096 Aug 11 01:49 floppy
drwxrwxrwx 1 root root   40 Dec 21 16:00 giga

I want to suppress the write permissions on Sigma and SigmaX. So I did

Sirrah ~ # chmod 555 /mnt/Sigma

That worked all right, and I went on with

Sirrah ~ # chmod 555 /mnt/SigmaX
chmod: changing permissions of `/mnt/SigmaX': Read-only file system

The error here is surprising, as SigmaX is mounted rw:

Sirrah ~ # mount
...
/dev/hda11 on /mnt/SigmaX type hfsplus (rw)
...

I tried the step of remounting it rw: the error disappeared, but chmod 
produced no result.
SigmaX, strangely, belongs to the cdrw group, and I wondered if that 
could be the cause of the trouble, so I tried to change it to root; but 
the answer was again: Read-only file system.
Finally, I wondered if SigmaX might have the "i" attribute, so I tried:

Sirrah ~ # lsattr /mnt
------------- /mnt/cdrom
------------- /mnt/floppy
lsattr: Inappropriate ioctl for device While reading flags on /mnt/giga
------------- /mnt/Sigma
------------- /mnt/SigmaX

It shows no attributes, but there is this error about giga: it is 
perhaps of no consequence, but it should not be there!

I'd be grateful for any hints that could help me get out of this mess.

Charles