diff --git a/sim_defs.h b/sim_defs.h
index ce77bf7..f6e085d 100644
--- a/sim_defs.h
+++ b/sim_defs.h
@@ -591,6 +591,7 @@ struct UNIT {
     uint16              us9;                            /* device specific */
     uint16              us10;                           /* device specific */
     void                *tmxr;                          /* TMXR linkage */
+    uint32              recsize;                        /* Tape info */
     t_bool              (*cancel)(UNIT *);
     double              usecs_remaining;                /* time balance for long delays */
     char                *uname;                         /* Unit name */