diff --git a/specplus3.c b/specplus3.c
index f7e1adeb..e9db5e78 100644
--- a/specplus3.c
+++ b/specplus3.c
@@ -460,7 +460,7 @@ specplus3_disk_insert( specplus3_drive_number which, const char *filename )
   struct flock lock;
   size_t i; int error;
 
-  if( which < SPECPLUS3_DRIVE_A || which > SPECPLUS3_DRIVE_B ) {
+  if( which > SPECPLUS3_DRIVE_B ) {
     ui_error( UI_ERROR_ERROR, "specplus3_disk_insert: unknown drive %d\n",
 	      which );
     fuse_abort();
@@ -552,7 +552,7 @@ specplus3_disk_eject( specplus3_drive_number which )
 {
   int error;
 
-  if( which < SPECPLUS3_DRIVE_A || which > SPECPLUS3_DRIVE_B ) {
+  if( which > SPECPLUS3_DRIVE_B ) {
     ui_error( UI_ERROR_ERROR, "specplus3_disk_eject: unknown drive %d\n",
 	      which );
     fuse_abort();
diff --git a/specplus3.h b/specplus3.h
index e80a0c29..39639253 100644
--- a/specplus3.h
+++ b/specplus3.h
@@ -60,7 +60,7 @@ void specplus3_memoryport_write(WORD port, BYTE b);
 /* The +3's drives */
 
 typedef enum specplus3_drive_number {
-  SPECPLUS3_DRIVE_A = 0,
+  SPECPLUS3_DRIVE_A = 0,	/* First drive must be number zero */
   SPECPLUS3_DRIVE_B,
 } specplus3_drive_number;