Thanks for the warning, Werner.

I was expecting the limit was 4 Gb, but I seem to remember there IS some
uncertainty as to whether 2 Gb or 4 Gb is the limit. You've apparently
'been there, done that'. If I understand you correctly, if I have a
KNOPPIXn that is compressed to 2 Gb or more it will cause trouble
expanding it on /tmp. Is that any different than expanding it to /?
I'm assuming 2.5:1 compression here.

I would have expected I might be able to
conjure up a KNOPPIX-DATA of about 10 Gb and store that as 4 Gb cloop
compressed on /mnt-system and sometime or other expand it again to
10 Gb on /. All this assuming no file in KNOPPIX-DATA ever exceeds 4 Gb.

Since my overlays are always incremental, small additions, I don't think
this is a problem if I am limited to 5 Gb in reiser terms and compressed
to 2 Gb on Fat32 on /mnt-system, but I can see this would be a problem
for re-mastering.

My understanding is that the limit is not a Fat32 limit per se, but
rather a limit of iso9660 filesize ON fat32 filesystems.