you mean recovering data after the kernel screwed up?
or booting problem?
or corrupted data?
or kernel panick?
why should you reinstall it?.
maybe you want to be more specific when you mean 'crash'
I think the moral is, : always backup the important data.
You can just zip and transfer it to your school account. That's one of the safest place.
If you need to recover, I think it's very hard. We have had once with ReCom server.
We can't get into the system. And the system just didn't boot.
So, we insert the rescue-disk (YOu Must Have This! ), go into the system,
spending around 7hours (around 5 pm - 12.00 am. ) trying bunch of methods, including trying to burn the data into CD, but to no avail.
At last, we manage to copy the data using scp command, tar-zip it, and transfer it to our school account.
(and the problem behave differently from time to time. At that time, we can hardly run ANY command , not even ls command. Strangely, we can use Windoz's dir command. )
So, I don;t think there's one method that manage you to always recover the data. The most important thing when you have problem( classic would be booting problem,) always have rescue disk with you.
And always back-up the data.
After that, you usually want to reinstall Linux again. (since it may corrupt you other data if you keep using it).