diff --git a/PDP8/pdp8_lp.c b/PDP8/pdp8_lp.c
index c1f40534..092758b6 100644
--- a/PDP8/pdp8_lp.c
+++ b/PDP8/pdp8_lp.c
@@ -177,6 +177,7 @@ t_stat lpt_attach (UNIT *uptr, CONST char *cptr)
 {
 t_stat reason;
 
+sim_switches |= SWMASK ('A');   /* Default to Append to existing file */
 reason = attach_unit (uptr, cptr);
 lpt_err = (lpt_unit.flags & UNIT_ATT) == 0;
 return reason;
diff --git a/PDP8/pdp8_pt.c b/PDP8/pdp8_pt.c
index 404a2524..a2a16209 100644
--- a/PDP8/pdp8_pt.c
+++ b/PDP8/pdp8_pt.c
@@ -46,6 +46,7 @@ t_stat ptr_svc (UNIT *uptr);
 t_stat ptp_svc (UNIT *uptr);
 t_stat ptr_reset (DEVICE *dptr);
 t_stat ptp_reset (DEVICE *dptr);
+t_stat ptp_attach (UNIT *uptr, CONST char *cptr);
 t_stat ptr_boot (int32 unitno, DEVICE *dptr);
 const char *ptr_description (DEVICE *dptr);
 const char *ptp_description (DEVICE *dptr);
@@ -123,7 +124,7 @@ DEVICE ptp_dev = {
     "PTP", &ptp_unit, ptp_reg, ptp_mod,
     1, 10, 31, 1, 8, 8,
     NULL, NULL, &ptp_reset,
-    NULL, NULL, NULL,
+    NULL, &ptp_attach, NULL,
     &ptp_dib, 0, 0,
     NULL, NULL, NULL, NULL, NULL, NULL,
     &ptp_description
@@ -260,6 +261,14 @@ sim_cancel (&ptp_unit);                                 /* deactivate unit */
 return SCPE_OK;
 }
 
+/* Attach routine */
+
+t_stat ptp_attach (UNIT *uptr, CONST char *cptr)
+{
+sim_switches |= SWMASK ('A');   /* Default to Append to existing file */
+return attach_unit (uptr, cptr);
+}
+
 /* Bootstrap routine */
 
 #define BOOT_START 07756
diff --git a/doc/pdp8_doc.doc b/doc/pdp8_doc.doc
index 4c22ce7f..ed1ef084 100644
Binary files a/doc/pdp8_doc.doc and b/doc/pdp8_doc.doc differ