diff --git a/libsrc/atari/atari.inc b/libsrc/atari/atari.inc
index 6d5a87d5c..9b732fd18 100644
--- a/libsrc/atari/atari.inc
+++ b/libsrc/atari/atari.inc
@@ -1041,14 +1041,18 @@ ATRRW	= $1F		;RIGHT-ARROW
 sst_flag     = 0	; length 1
 sst_sectsize = 1	;        2
 sst_driveno  = 3	;        1  (drive #)
-;sst_id	     = 3	;        1  (to make size power of 2, used as
-;;				    test for valid pointer, must contain
-;;				    $CD)
-;SSTIDVAL     = $CD
-
 sst_size     = 4	; size of one entry
 			; if changed, adapt diopncls.s
 
+;-------------------------------------------------------------------------
+; OFFSETS INTO _dio_phys_pos
+;-------------------------------------------------------------------------
+
+diopp_head   = 0	; head
+diopp_track  = 1	; track / cylinder
+diopp_sector = 3	; sector
+diopp_size   = 5	; size of structure
+
 ;-------------------------------------------------------------------------
 ; End of atari.inc
 ;-------------------------------------------------------------------------