Ooh! Well looky here (/proc/mounts):

/dev/root / ext2 rw 0 0

none /proc proc rw 0 0

/dev/hda4 /drive0 ext2 rw 0 0

/dev/hdc4 /drive1 ext2 ro 0 0

Notice - drive1 is ro. I did an rw but not an rwm (yet) at this point. If I do an rwm I get back "mount: can't find /drive1 in /etc/fstab or /etc/mtab" - and hence I figure it needs to go in there.

It's weird 'cause /drive1 is already mounted (it's in /proc/mounts - didn't think to look there, thanks!) but I'd think it needs to be in /etc/fstab (at least in the interest of playing nice and all that).

Since I've been getting all these warnings and such, the lack of /drive1 from /etc/fstab seemed to match up with that.

OK then - I added it in. rwm works now. Yay! rom works as well. Also yay. Grazie.