 
  Use to copy the file currently displayed in the active view
window from memory to disk. The file remains in memory.
 
With Save As you can save to a different file than the one
you loaded your program from, preserving the original
version.
 
Tip: Save (Full Menus only) is faster than Save As, but
     Save always overwrites the disk file from which the
     current file was loaded. Save All (Full Menus only) is
     used when you are working on multiple-module programs.