diff --git a/libsrc/atari/atari.inc b/libsrc/atari/atari.inc
index 4064b8a09..f7c0c43dd 100644
--- a/libsrc/atari/atari.inc
+++ b/libsrc/atari/atari.inc
@@ -1085,6 +1085,15 @@ diopp_track  = 1	; track / cylinder
 diopp_sector = 3	; sector
 diopp_size   = 5	; size of structure
 
+;-------------------------------------------------------------------------
+; VALUES for dos_type
+;-------------------------------------------------------------------------
+
+ATARIDOS     = 0
+SPARTADOS    = 1
+OSADOS       = 2	; OS/A+
+MYDOS        = 3
+
 ;-------------------------------------------------------------------------
 ; End of atari.inc
 ;-------------------------------------------------------------------------