These are used in the Register and Login forms.
And, the deprecated CreatePageDir is replaced by CreateDir (fixes a bug
introduced by Oddmuse version 2.3.0).
Recent GNU/Linux systems use ext3 or ext4 file systems. These use HTree
to index files. Wikipedia says: "HTree indexing improved the scalability
of Linux ext2 based filesystems from a practical limit of a few thousand
files, into the range of tens of millions of files per directory. [...]
HTree indexes are available in ext3 when the dir_index feature is
enabled. [...] HTree indexes are turned on by default in ext4."
Thus, instead of working on balanced-page-directories.pl, we decided to
get rid of these sub-directories altogether.
Unfortunately, this is backwards incompatible. Users wanting to upgrade
will need to install the upgrade.pl extension in order to upgrade the
file database.
