(a) the TITLE of web pages is
HDFS: <directory name>
for directories and files, correspondingly.
trimmed from the right, if too long.
(This helps finding browser windows, tabs, navigating history, and creating bookmarks)
(b) instead of or in addition to "go to parent directory" link, each element of the path displayed at the top of the page should link to the corresponding directory.
This also saves a line in display.
(c) the file browsing page should not automatically refresh.
(d) it would be nice to use the whole window rather than the text box for viewing.
Wrapping is often harmful.
(These may be a radio-button options option saved in a cookie)