diff --git a/NOVA/nova_mta.c b/NOVA/nova_mta.c
index 7809d04a..5e8c443d 100644
--- a/NOVA/nova_mta.c
+++ b/NOVA/nova_mta.c
@@ -1,6 +1,6 @@
 /* nova_mta.c: NOVA magnetic tape simulator
 
-   Copyright (c) 1993-2022, Robert M. Supnik
+   Copyright (c) 1993-2023, Robert M. Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -25,6 +25,7 @@
 
    mta          magnetic tape
 
+   02-Nov-23    RMS     Mode change should test STA_BOT, not sim_tape_BOT
    26-Mar-22    RMS     Added extra case points for new MTSE definitions
    13-Mar-17    RMS     Annotated fall through in switch
    04-Jul-07    BKR     fixed boot code to properly boot self-boot tapes;
@@ -371,7 +372,7 @@ else switch (c) {                                       /* case on command */
         break;
 
     case CU_DMODE:                                      /* drive mode */
-        if (!sim_tape_bot (uptr))                       /* must be BOT */
+        if ((uptr->USTAT & STA_BOT) == 0)               /* must be BOT */
             mta_sta = mta_sta | STA_ILL;
         else mta_upddsta (uptr, (mta_cu & CU_PE)?       /* update drv status */
             uptr->USTAT | STA_PEM: uptr->USTAT & ~ STA_PEM);
diff --git a/PDP11/pdp11_cpumod.c b/PDP11/pdp11_cpumod.c
index ea877a11..6ec84f73 100644
--- a/PDP11/pdp11_cpumod.c
+++ b/PDP11/pdp11_cpumod.c
@@ -695,8 +695,8 @@ return SCPE_NXM;                                        /* unimplemented */
 t_stat CPU70_wr (int32 data, int32 pa, int32 access)
 {
 switch ((pa >> 1) & 017) {                              /* decode pa<4:1> */
-    case 000:
-    case 001:
+    case 000:                                           /* low error */
+    case 001:                                           /* high error */
         return SCPE_OK;                                 /* error addr */
 
     case 002:                                           /* MEMERR */
diff --git a/PDP11/pdp11_dz.c b/PDP11/pdp11_dz.c
index 5be89e76..400b2518 100644
--- a/PDP11/pdp11_dz.c
+++ b/PDP11/pdp11_dz.c
@@ -1,6 +1,6 @@
 /* pdp11_dz.c: DZ11 terminal multiplexor simulator
 
-   Copyright (c) 2001-2008, Robert M Supnik
+   Copyright (c) 2001-2023, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -25,6 +25,7 @@
 
    dz           DZ11 terminal multiplexor
 
+   23-Feb-23    RMS     Fixed line number calculation in connect (Walter Mueller)
    29-Dec-08    RMS     Added MTAB_NC to SET LOG command (Walter Mueller)
    19-Nov-08    RMS     Revised for common TMXR show routines
    18-Jun-07    RMS     Added UNIT_IDLE flag
diff --git a/PDP11/pdp11_rk.c b/PDP11/pdp11_rk.c
index 84d0cedd..7f626fd2 100644
--- a/PDP11/pdp11_rk.c
+++ b/PDP11/pdp11_rk.c
@@ -734,7 +734,7 @@ if (wc && (err == 0)) {                                 /* seek ok? */
                 rkxb[i] = comp;
             }
         else {                                          /* normal fetch */
-            if ((t = MAP_RDW (ma, wc << 1, rkxb))) {  /* get buf */
+            if ((t = MAP_RDW (ma, wc << 1, rkxb))) {    /* get buf */
                 rker = rker | RKER_NXM;                 /* NXM? set flg */
                 wc = wc - (t >> 1);                     /* adj wd cnt */
                 }
diff --git a/PDP11/pdp11_ts.c b/PDP11/pdp11_ts.c
index 7da3e141..940942d2 100644
--- a/PDP11/pdp11_ts.c
+++ b/PDP11/pdp11_ts.c
@@ -544,7 +544,7 @@ do {
         msgrfc = fc;
     if ((st = sim_tape_sprecf (uptr, &tbc)))            /* space rec fwd, err? */
         return ts_map_status (st);                      /* map status */
-        ts_set_mot (0);                                 /* tape has moved, !BOT */
+    ts_set_mot (0);                                     /* tape has moved, !BOT */
     } while (fc != 0);
 return 0;
 }
diff --git a/PDP18B/pdp18b_fpp.c b/PDP18B/pdp18b_fpp.c
index 65427275..45931fbc 100644
--- a/PDP18B/pdp18b_fpp.c
+++ b/PDP18B/pdp18b_fpp.c
@@ -379,7 +379,7 @@ return SCPE_OK;
 
 t_stat fp15_opnd (int32 ir, int32 addr, UFP *fpn)
 {
-int32 i, numwd, wd[3];
+int32 i, numwd, wd[3] = { 0,0,0 };
 
 fguard = 0;                                             /* clear guard */
 if (ir & FI_NOLOAD)                                     /* no load? */
@@ -426,7 +426,7 @@ return FP_OK;
 
 t_stat fp15_store (int32 ir, int32 addr, UFP *a)
 {
-int32 i, numwd, wd[3];
+int32 i, numwd, wd[3] = { 0,0,0 };
 t_stat sta;
 
 fguard = 0;                                             /* clear guard */
diff --git a/PDP8/pdp8_mt.c b/PDP8/pdp8_mt.c
index e9e5105a..0e430c32 100644
--- a/PDP8/pdp8_mt.c
+++ b/PDP8/pdp8_mt.c
@@ -1,6 +1,6 @@
 /* pdp8_mt.c: PDP-8 magnetic tape simulator
 
-   Copyright (c) 1993-2022, Robert M Supnik
+   Copyright (c) 1993-2023, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -25,6 +25,7 @@
 
    mt           TM8E/TU10 magtape
 
+   01-Nov-23    RMS     Fixed illegal op test to use BOT flag
    26-Mar-22    RMS     Added extra case points for new MTSE definitions
    16-Feb-06    RMS     Added tape capacity checking
    16-Aug-05    RMS     Fixed C++ declaration and cast problems
@@ -270,7 +271,7 @@ switch (IR & 07) {                                      /* decode IR<9:11> */
         if (((uptr->flags & UNIT_ATT) == 0) ||
               sim_is_active (uptr) ||
            (((f == FN_WRITE) || (f == FN_WREOF)) && sim_tape_wrp (uptr))
-           || (((f == FN_SPACER) || (f == FN_REWIND)) && sim_tape_bot (uptr))) {
+           || (((f == FN_SPACER) || (f == FN_REWIND)) && (uptr->USTAT & STA_BOT))) {
             mt_sta = mt_sta | STA_ILL | STA_ERR;        /* illegal op error */
             mt_set_done ();                             /* set done */
             mt_updcsta (uptr);                          /* update status */
diff --git a/PDP8/pdp8_sys.c b/PDP8/pdp8_sys.c
index 70ee98f7..55962b80 100644
--- a/PDP8/pdp8_sys.c
+++ b/PDP8/pdp8_sys.c
@@ -1,6 +1,6 @@
 /* pdp8_sys.c: PDP-8 simulator interface
 
-   Copyright (c) 1993-2021, Robert M Supnik
+   Copyright (c) 1993-2023, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),