> then I looked up the manpage for mount and figured out that
> I probably had to divide the number by 1024 (23328).
Just use the number shown by dumpe2fs, they are block numbers.
  The group number won't help, either.

> # mount /dev/hda1 /mnt/linux -o sb=3D23328 mount: wrong fs type, bad
> option, bad superblock on /dev/hda1, missing codepage or other error
> In some cases useful info is found in syslog - try dmesg | tail or so
You need to add the file system type:

  # mount -t ext3 /dev/hda1 /mnt/linux -o sb=3DADDR

> So I tried it with a -b argument of 23887872 (I know that's several
> orders of magnitude higher than the example. This is unix; for all I
> know the example could have been written in 1972).
e2fsprogs are fairly recent stuff; moreover, the second extended file
system was developed around 1993.

> Using an argument of 23328 gives a "bad magic number" message the same
> as before. I've also tried the above with the superblocks at 32768 and
> I guess I could go through them all, one by one, if you think
> it might help.
You should try them all to be sure.  It will be easier now that I've
clarified what numbers must be used.
  "Bad magic number" means that the block could not be identified as
super block because a fixed number identifying super blocks was not
found.

> Let's say I have a vague notion that there's an inode table somewhere
> on my disk, and this has pointers to the raw data that makes up my
> files. So the super block is the bit that points to the inode table?
Without the super block you will have problems identifying the group
descriptors, which in turn contain inode information.
  But dumpe2fs already found some groups.  Can you give me the
information dumpe2fs put out right at the beginning?
You could try working with 'debugfs' as a last resort.

> And probably contains other interesting stuff about the filesystem,
> like the fact that it's ext3 instead of ext2.
Correct.