I did have a live cd lying around somewhere, but that was not of great help. "cfdisk" absolutely refused to run. I could not mount from a terminal in the liveCD
( mount -t ext3 /dev/mapper/isw_xxxxxxx /mnt/target )
resulting in "superblock errors" or "partition could not be recognized" and those sorts of things.
and from within "grub", it couldn't even see /boot/grub/stage1. setup (hd0) didn´t work either.
Well, searching around on the internet seems to regularly suggest to use the "grub" trick, or suggests that the root (hdx,y) setting is incorrect, but my problem clearly was a hosing of the entire file system. I thought.
Well, since I am running from a fake RAID array, I needed to remember to install "dmraid" (intrepid has this by default now), but in feisty that needed to be activated through the sources.list first, then apt-get updated and then installed. Then perform "dmraid -ay" to get the /dev/mapper devices to work.
It makes no sense to mount a RAID-ed partition directly through /dev/sda2. You should remember that as well :). On the internet, I couldn't see very good pointers, but eventually I decided to finish where the single user mode left off: fsck.
root@recife# fsck -y /dev/mapper/isw_xxxxxxxx02
eventually ran the entire file system check and resolved looooads of errors. Mounting this on /mnt/target later did work. I could also sort of boot into the system, but because /etc was gone, it wasn't very helpful :). So the entire system got hosed, but from the Live CD system, I could rescue a couple of important files and put them onto different systems or mail them around. Thus, I didn't lose my university assignments and what have you, but the entire installed system is a loss.
I've now re-installed intrepid from the netboot cd (download from the internet) and that worked in one go. There's a guide on the internet on how to install that for fakeraid systems. It's a lot easier. Grub however still has problems getting things organized, so you should pay heed there. Also, it seems that "update-grub" doesn't work properly when menu.lst does not exist. Actually, it does attempt to ask you if it should be generated, but that doesn't work well. I ended up creating a single file "line" with a "y
On reboot, things already worked fine, but I like to install the nvidia restricted module drivers for better performance. The screen resolution for my IIyama was still problematic though. It only got to 1024x768. Eventually, I ran nvidia-xconfig, which put in more crap into xorg.conf, then restarted xorg ( nohup /etc/init.d/gdm restart ), after which I had more options to choose from.
Right now, I think I've more or less entirely upgraded to the system I had, so I can carry on hacking and doing things. For some reason, the old system was slowing down significantly. And then there's not even a heavy registry to be supported.