InfoDir for

From Point Inception:

With the infoDir program you may arrange items in a hierarchical manner or an upside-down tree structure, the same way files are organized in a typical computer system. The top level directory or folder is indicated by /. Tap on the any of the new button icons to create a new directory, a new memo or a new event at the current directory. To view or edit an item, tap on the items's name or icon. To move to a subdirectory, tap on the directory's name. To move one level up in the directory tree, tap on the up icon. Only empty directories can be deleted. Directories may be renamed or deleted by selecting the correct item from the menu.