diff --git a/INSTALL b/INSTALL
index e500002d..56e62818 100644
--- a/INSTALL
+++ b/INSTALL
@@ -22,10 +22,11 @@ SDL_Net
 
 SDL_Sound 
     For compressed audio on diskimages. (optional)
+    This is for cue/bin cdrom images with compressed (mp3/ogg) audio tracks.
 
 ALSA_Headers
     (optional)
-    ???????? for Alsa support under linux
+    for Alsa support under linux. Part of the linux kernel sources
 
 If you want compile from the CVS under a unix system, you'll also need 
 automake (>=1.6), autoconf(>=2.50). Should be available at http://www.gnu.org