Is it possible to pass from swap to ext3 without formating the partition ?
I had problems with my swap that was on hdc5, and I ran the command 'mkswap' on hdc6, the wrong partition, the one with
'/' label. And now I cannot access to the system, all data including... I wonder if I can do smth with that. Because I don't really want to reinstall the system.

It is really stupid, but it happens.

Thanks.

You have already formatted the system with mkswap, you need to reinstall, sorry.

I remember that it takes me about 5 minutes to format ext3, but it took only several seconds to format swap. Was it smth like quick format ?

REINSTALL??????? right. The is the most stupid answer I have seen.

simply use fdisk to change the type and then mke2fs the filesystem.

Of course mke2fs takes longer, ext2 is a filesystem, white swap is simply a mapping.

the way i read it his root is hdc6, if he formats it, he must reinstall.

Ahh sh_t. It is just my pet peeve where such a common suggest to any problem is to reinstall the entire system, so STUPIDLY, I did not read the post entirely. :-( Forgive me.

If hdc6 was the root partition and therefore mounted, I am kind of surprised mkswap would run. I will have to test that out (not of course on anything essential).

There is always the possibility of restoring the root partition from the backup (there is a backup is there not). There is also the possibility of booting with a boot disk and running mke2fs to restore the superblocks. See man mke2fs, the -S option. I do not know the actual effects of mkswap, but it may be worth a try.

No problem, i see that answer too much as well.
There may be a way to restore, such as restoring the superblocks, i'm not sure.
I very much doubt there is a backup of the entire root filesystem though.

Hopefully you haven't done anything drastic yet to change the contents on the partition. You may still be able to recover your info. mkswap only overwrites the superblock on the partition, so you should still be able to recover the contents by repairing it with a backup superblock. You have to boot up linux on a different partition or one that resides in memory. Either use a live-cd installation(knoppix), a linux-on-a-floppy(tomsrtbt), or install linux on another partition. After you have it booting in the other linux system, do a e2fsck on /dev/hdc5. Unless the partition is seriously corrupted, you should be able to get back your info.