Shrinking the Extended Directory

This is my question, some modules on my server could not be unloaded properly, while try to unload them the server hanged and I was forced to turn the server of and restart it. None of the conventional methods for downing the server worked(crtl,alt,esc or Shift,shift,alt,esc). When the sever restarted I check the conlog file and saw this information for some volumes that were mounted. Reading fat,verfiying directory fat chain,scanning the directories,checking subdir,scannig files...etc. After these normal events I saw the statement, Shrinking the Extended Dir, with a list of; Problems with file xxxxxxxx.xxx,length extended and old length=0, new lenght=65536, does anyone know what this means or can someone point me to some documentation on this ?