Hi George,
Its always been my belief that large folders cause multi level
directory block chaining in traditional UNIX fs.
I expect the majority of nmh users are using ext3 or ext4 filesystems,
as shown by ‘df -T’, though perhaps we have many Apple users who have
something else. I don't think ext* still use Thompson's original
approach of levels of data blocks to hold the extra (filename, inode)
pairs.
What I've found a problem with ext* filesystems is when a directory has
millions of files. Deleting them took a week because I had to remove
them in small batches with seconds of pause between to allow the machine
to recover. But Norm's some way under that. :-)
--
Cheers, Ralph.