So I got up this morning (on the west coast, as you hoped), booted up into knoppix again, and started backing up my MBR and first sector of each partition. Then I noticed an icon on the knoppix desktop listing hda7 as a mountable partition, so I thought I'd try it again. Exactly the same way as last night,
sudo mount /dev/hda7 /mnt but it mounted!!! No errors. So I immediately backed up off-site everything I might possibly need, including the MBR and first sectors of each partition. Then rebooted without knoppix, making no changes, and success! I even have the two new partitions I wanted. I remember now that cfdisk warns you that you may need to reboot in order to read the new partition table properly, but it just didn't occur to me this time. I'm sure glad I didn't start deleting and re-creating the partition table. Several lessons learned, a _relatively_ easy way: 1. backups don't count unless you have them on hand 2. in addition to data, back up the MBR and first sector of each partition before messing with the partition table: dd if=/dev/hda of=hda.mbr bs=512 count=1 dd if=/dev/hdax of=hdax.mbr bs=512 count=1 3. after changing your partition table, you really do have to reboot - at least this is my best guess as to what the problem was. Thank you for all your efforts Mike! I'll return the favour to someone if I can't to you :)
