Thanks for pointing out this kernel module! There exist others (e. g. transparency) which aim to do the same but so far they all had problems with the way Knoppix uses symbolic links.

I have donwloaded this one and did:

Code:
sudo su
unp mini_fo-0-5-9.tar.bz2
cd mini_fo
make
insmod ./mini_fo.o
The kernel module loaded successful, dmesg says "
Registering mini_fo version $Id: main.c,v 1.5 2004/04/02 14:42:53 wd Exp $". Wow. Now I tried to make /KNOPPIX/ writeable:

Code:
mkdir /tmp/mini_fo
mount -t mini_fo -o dir=/KNOPPIX/,dir2=/tmp/mini_fo/ /KNOPPIX/ /KNOPPIX/
Worked great! Now I can create subdirectories and files just where I want:

Code:
mkdir /usr/share/test
touch /usr/share/test/test.txt
Everything seems writeable, so why not try apt?

Code:
root@1[test]# apt-get update
Speicherzugriffsfehler
ooops! Something went wrong...
This is what dmesg says:
Code:
Unable to handle kernel NULL pointer dereference at virtual address 00000010
 printing eip:
c8c99ff5
*pde = 00000000
Oops: 0000
mini_fo af_packet orinoco_cs orinoco hermes autofs4 reiserfs ext3 jbd ymfpci ac97_codec uart401 sound soundcore serial usb-uhci usbcore ds yenta_socket pcmcia_core apm rtc cloop
CPU:    0
EIP:    0010:[<c8c99ff5>]    Tainted: P
EFLAGS: 00010282
eax: c16fd3e0   ebx: 00000000   ecx: c8ca0b24   edx: c8ca0cdf
esi: 00000000   edi: c5866f90   ebp: c5c03f3c   esp: c5c03f14
ds: 0018   es: 0018   ss: 0018
Process apt-get (pid: 19789, stackpage=c5c03000)
Stack: 00000004 c8ca0b24 c8ca3aa0 c8ca0cdf c8ca0b0e 000002ea c5866f90 c5c03f68
       c44be120 c5c03f78 00000000 c014fa6d c44be120 00000006 c5866f90 00000004
       ffffffea bffff2d0 00000004 fffffff7 c5866f90 00000001 00000000 00000000
Call Trace: [<c8ca0b24>]  [<c8ca3aa0>]  [<c8ca0cdf>]  [<c8ca0b0e>]  [<c014fa6d>]  [<c014b69a>]  [<c014b84d>]  [<c0108a67>]
Code: 8b 43 10 8b 50 34 85 d2 74 61 89 7c 24 08 b9 05 00 00 00 89
 <1>Unable to handle kernel NULL pointer dereference at virtual address 00000010
 printing eip:
c8c99ff5
Now I am stuck. What say the wizards here?

probono