So the disk developed a new I/O error, so there is now way around replacing it.
First however, I need once again to get the files of the disk. I now realize that I saved much too little details from the last attempt, so this is an attempt to be more specific.
I have decided to use the same solution as the last time, that is to boot the MBA up on the install DVD and transfer the files to my powermac over a crossed ethernet cable directly to the powermac. I have however heard about a possible easier way. Apparently when starting the MBA up in target mode (holding down the T key during boot), the MBA will appear over a USB as just a USB drive. I have always thought that would only work over firewire (which the MBA does not have) and it is quite possible it would require either a newer mac or a windows machine in the other end, but if it works it would be much simpler.
Anyway, back to the ethernet approach. In my setup I have the MBA connected to a USB hub into which I have connected an external (LaCie) CD drive and the MBA ethernet adapter. The CD drive has the install DVD in it and the ethernet is connected directly to the powermac. On the powermac, internet sharing has been enabled (in Options->Sharing). Then MBA is booted up on the CD (hold down the C key during boot) and after selecting language, I start a terminal from the Utilities menu (rather than continuing the actual install). In the terminal, I check that I have connectivity to the powermac (with ping). The installation program will automatically start and configure the ethernet network. You can also enable wireless networking but if you want to copy a large amount of files, it can take a really log time.
The first complication is to find a way to copy the files over the network. I am using MacPorts so I have `rsync' buried somewhere on the disk, but rsync both needs some libraries and access to `ssh' in order to work, so one needs to prepare the environment on the MBA terminal as follows:
export DLD_LIBRARY_PATH=/Voumes/Macintosh\ HD/opt/local/lib
Here we assume the MBA disk is called "Macintosh HD". Note also that command are typed in, partly from memory, so there may be some inaccuracies or typos, so be prepared.
Now we are ready to copy the files over:
rsync -av /Volumes/Macintosh HD/. <userid>@192.168.3.1:/Volumes/Old/MBA/
The internet sharing assigned 192.168.3.1 to the powermac. <userid> refers to your userid on the receiving end.
(more to come)