diff --git a/PDP10/ka10_cpu.c b/PDP10/ka10_cpu.c
index e3437a6..b2911f7 100644
--- a/PDP10/ka10_cpu.c
+++ b/PDP10/ka10_cpu.c
@@ -664,7 +664,6 @@ int check_irq_level() {
 
 void restore_pi_hold() {
      int i, lvl;
-     int pi_ok, pi_t;
 
      if (!pi_enable)
         return;
@@ -739,8 +738,8 @@ t_stat dev_pag(uint32 dev, uint64 *data) {
        *data = res;
        sim_debug(DEBUG_DATAIO, &cpu_dev, "DATAI PAG %012llo\n", *data);
        break;
-    return SCPE_OK;
     }
+    return SCPE_OK;
 }
 
 t_stat dev_apr(uint32 dev, uint64 *data) {
@@ -934,7 +933,6 @@ int page_lookup(int addr, int flag, int *loc, int wr) {
     uint64   data;
     int      base;
     int      page = addr >> 9;
-    int      pg;
     int      uf = 0;
 
     if (flag) {
@@ -1076,7 +1074,7 @@ int Mem_read(int flag) {
         sim_interval--;
         if (!page_lookup(AB, flag, &addr, 0))
             return 1;
-        if (addr > MEMSIZE) {
+        if (addr > (int)MEMSIZE) {
             nxm_flag = 1;
             set_interrupt(0, apr_irq);
             return 1;
@@ -1098,7 +1096,7 @@ int Mem_write(int flag) {
         if (private_page)
             return 1;
 #endif
-        if (addr > MEMSIZE) {
+        if (addr > (int)MEMSIZE) {
             nxm_flag = 1;
             set_interrupt(0, apr_irq);
             return 1;
@@ -1159,7 +1157,7 @@ if ((reason = build_dev_tab ()) != SCPE_OK)            /* build, chk dib_tab */
 
   while ( reason == 0) {                                /* loop until ABORT */
      if (sim_interval <= 0) {                           /* check clock queue */
-          if (reason = sim_process_event () != SCPE_OK) {    /* error?  stop sim */
+          if ((reason = sim_process_event()) != SCPE_OK) {/* error?  stop sim */
                 if (reason != SCPE_STEP || !BYF5)
                    return reason;
           }
@@ -1205,7 +1203,6 @@ fetch:
 
     /* Update history */
     if (hst_lnt) {
-            int i;
             hst_p = hst_p + 1;
             if (hst_p >= hst_lnt)
                     hst_p = 0;
@@ -1236,7 +1233,7 @@ fetch:
                  goto last;
          /* Handle events during a indirect loop */
          if (sim_interval-- <= 0) {
-              if (reason = sim_process_event () != SCPE_OK) {
+              if ((reason = sim_process_event()) != SCPE_OK) {
                  if (reason != SCPE_STEP || !BYF5)
                      return reason;
               }
@@ -2192,7 +2189,7 @@ fxnorm:
                  break;
               }
 #if !KI
-              if ((BR == SMASK))              /* Handle special case */
+              if (BR == SMASK)                /* Handle special case */
                  flag3 = !flag3;
 #endif
               MQ = AR * (BR & RMASK);         /* 36 * low 18 = 54 bits */
@@ -2295,7 +2292,6 @@ fxnorm:
                       AR = (AR + 1) & FMASK;
                   flag1 = 1;
               }
-div:
               if (BR & SMASK)
                    AD = (AR + BR) & FMASK;
               else
@@ -2507,7 +2503,7 @@ div:
               BR = AB;
               do {
                  if (sim_interval <= 0) {
-                      sim_process_event ();
+                      sim_process_event();
                  }
                  /* Allow for interrupt */
                  if (pi_enable && pi_pending) {
@@ -3528,11 +3524,8 @@ for (i = 0; (dptr = sim_devices[i]) != NULL; i++) {
               if (dibp->io) {                           /* any dispatch? */
                    if (dev_tab[(dibp->dev_num >> 2) + j] != &null_dev) {
                                                        /* already filled? */
-                           printf ("%s device number conflict at %02o\n",
-                              sim_dname (dptr), dibp->dev_num + j << 2);
-                      if (sim_log)
-                        fprintf (sim_log, "%s device number conflict at %02o\n",
-                                   sim_dname (dptr), dibp->dev_num + j << 2);
+                       sim_printf ("%s device number conflict at %02o\n",
+                              sim_dname (dptr), dibp->dev_num + (j << 2));
                        return TRUE;
                    }
               dev_tab[(dibp->dev_num >> 2) + j] = dibp->io;  /* fill */
@@ -3566,7 +3559,7 @@ return SCPE_OK;
 t_stat cpu_show_serial (FILE *st, UNIT *uptr, int32 val, CONST void *desc)
 {
 fprintf (st, "Serial: " );
-if( (apr_serial == -1)) {
+if (apr_serial == -1) {
     fprintf (st, "%d (default)", DEF_SERIAL);
     return SCPE_OK;
     }
@@ -3611,7 +3604,6 @@ t_stat cpu_show_hist (FILE *st, UNIT *uptr, int32 val, CONST void *desc)
 int32 k, di, lnt;
 char *cptr = (char *) desc;
 t_stat r;
-int reg;
 t_value sim_eval;
 InstHistory *h;
 
diff --git a/PDP10/ka10_dc.c b/PDP10/ka10_dc.c
index bb1639b..b939f21 100644
--- a/PDP10/ka10_dc.c
+++ b/PDP10/ka10_dc.c
@@ -81,7 +81,6 @@ uint32   dc_ring;                                 /* Connection pending */
 uint32   rx_conn;                                 /* Connection flags */
 extern int32 tmxr_poll;
 
-DEVICE dc_dev;
 t_stat dc_devio(uint32 dev, uint64 *data);
 t_stat dc_svc (UNIT *uptr);
 t_stat dc_doscan (UNIT *uptr);
@@ -297,7 +296,7 @@ t_stat dc_devio(uint32 dev, uint64 *data) {
 
 t_stat dc_svc (UNIT *uptr)
 {
-int32 ln, c, temp;
+int32 ln;
 
     if ((uptr->flags & UNIT_ATT) == 0)                  /* attached? */
         return SCPE_OK;
@@ -334,7 +333,6 @@ int32 ln, c, temp;
 
 /* Scan to see if something to do */
 t_stat dc_doscan (UNIT *uptr) {
-   int ln;
    int32 lmask;
 
    uptr->STATUS &= ~(RCV_PI|XMT_PI);
diff --git a/PDP10/ka10_defs.h b/PDP10/ka10_defs.h
index 2c73e1a..1b64380 100644
--- a/PDP10/ka10_defs.h
+++ b/PDP10/ka10_defs.h
@@ -251,8 +251,8 @@ extern t_stat (*dev_tab[128])(uint32 dev, uint64 *data);
 #define VEC_DEVMAX      8                               /* max device vec */
 
 struct pdp_dib {
-    int                 dev_num;                        /* device address */
-    int                 num_devs;                       /* length */
+    uint32              dev_num;                        /* device address */
+    uint32              num_devs;                       /* length */
     t_stat              (*io)(uint32 dev, uint64 *data);
 };
 
diff --git a/PDP10/ka10_dk.c b/PDP10/ka10_dk.c
index bbbf3cd..76989ba 100644
--- a/PDP10/ka10_dk.c
+++ b/PDP10/ka10_dk.c
@@ -65,7 +65,6 @@
 
 extern UNIT cpu_unit;
 
-DEVICE dk_dev;
 t_stat dk_devio(uint32 dev, uint64 *data);
 void   dk_count (UNIT *uptr);
 t_stat dk_svc (UNIT *uptr);
@@ -91,7 +90,6 @@ DEVICE dk_dev = {
     };
 
 t_stat dk_devio(uint32 dev, uint64 *data) {
-    uint64      res;
     int         unit = (dev - DK_DEVNUM) >> 2;
     UNIT        *uptr = &dk_unit[unit];
     int32       t;
diff --git a/PDP10/ka10_dp.c b/PDP10/ka10_dp.c
index 2539a0c..b9701d6 100644
--- a/PDP10/ka10_dp.c
+++ b/PDP10/ka10_dp.c
@@ -69,7 +69,7 @@
 #define NXM_ERR         0000000010000      
 #define SLW_CHN         0000000020000
 #define SRC_ERR         0000000040000
-#define PWR_FAIL        0000000100000
+#define PWR_FAIL_10     0000000100000
 #define END_CYL         0000000200000      /* No effect */
 #define SRC_DONE        0000000400000      /* No effect */
 #define DSK_PRTY        0000001000000      /* No effect */
@@ -505,6 +505,7 @@ t_stat dp_devio(uint32 dev, uint64 *data) {
          sim_activate(uptr, 100);
          return SCPE_OK;
     }
+    return SCPE_OK; /* Unreached */
 }
 
 
@@ -746,7 +747,6 @@ dp_boot(int32 unit_num, DEVICE * dptr)
 
 t_stat dp_attach (UNIT *uptr, CONST char *cptr)
 {
-    int32 drv, i, p;
     t_stat r;
     DEVICE *dptr;
     DIB *dib;
@@ -772,8 +772,6 @@ t_stat dp_attach (UNIT *uptr, CONST char *cptr)
 
 t_stat dp_detach (UNIT *uptr)
 {
-    int32 drv;
-
     if (!(uptr->flags & UNIT_ATT))                          /* attached? */
         return SCPE_OK;
     if (sim_is_active (uptr))                              /* unit active? */
diff --git a/PDP10/ka10_dt.c b/PDP10/ka10_dt.c
index 3680b0f..9c28cfb 100644
--- a/PDP10/ka10_dt.c
+++ b/PDP10/ka10_dt.c
@@ -360,7 +360,6 @@ static const int32 map_unit[16] = {                     /* Type 550 unit map */
     0, -1, -1, -1, -1, -1, -1, -1
     };
 
-DEVICE dt_dev;
 int32 dt75 (int32 dev, int32 pulse, int32 dat);
 int32 dt76 (int32 dev, int32 pulse, int32 dat);
 t_stat dt_devio(uint32 dev, uint64 *data);
@@ -390,7 +389,6 @@ int32 dt_gethdr (UNIT *uptr, int32 blk, int32 relpos);
 DIB dt_dib = { DT_DEVNUM, 2, &dt_devio};
 
 UNIT dt_unit[] = {
-#if 0
     { UDATA (&dt_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+
              UNIT_ROABLE, DT_CAPAC) },
     { UDATA (&dt_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+
@@ -407,7 +405,6 @@ UNIT dt_unit[] = {
              UNIT_ROABLE, DT_CAPAC) },
     { UDATA (&dt_svc, UNIT_FIX+UNIT_ATTABLE+UNIT_DISABLE+
              UNIT_ROABLE, DT_CAPAC) }
-#endif
     };
 
 REG dt_reg[] = {
@@ -1581,6 +1578,8 @@ uptr->filebuf = NULL;                                   /* clear buf ptr */
 uptr->flags = uptr->flags & ~(UNIT_8FMT | UNIT_11FMT);  /* default fmt */
 uptr->capac = DT_CAPAC;                                 /* default size */
 return detach_unit (uptr);
+#else
+return SCPE_NOFNC;
 #endif
 }
 #endif
diff --git a/PDP10/ka10_lp.c b/PDP10/ka10_lp.c
index 1ce53a0..8cbf58a 100644
--- a/PDP10/ka10_lp.c
+++ b/PDP10/ka10_lp.c
@@ -52,7 +52,6 @@
 
 
 
-DEVICE          lpt_dev;
 t_stat          lpt_devio(uint32 dev, uint64 *data);
 t_stat          lpt_svc (UNIT *uptr);
 t_stat          lpt_reset (DEVICE *dptr);
@@ -131,7 +130,7 @@ t_stat lpt_devio(uint32 dev, uint64 *data) {
 
     case DATAO:
          if ((uptr->STATUS & BUSY_FLG) == 0) {
-             uptr->CHL = *data >> 15;
+             uptr->CHL = (int32)(*data >> 15);
              uptr->CHR = (*data >> 1) & 0037777;
              uptr->STATUS |= BUSY_FLG;
              uptr->STATUS &= ~DONE_FLG;
diff --git a/PDP10/ka10_mt.c b/PDP10/ka10_mt.c
index 073f571..7066d0f 100644
--- a/PDP10/ka10_mt.c
+++ b/PDP10/ka10_mt.c
@@ -213,7 +213,7 @@ t_stat mt_devio(uint32 dev, uint64 *data) {
        case CONO:
           unit = (*data >> 15) & 07;
           uptr = &mt_unit[unit];
-          uptr->u3 = *data;
+          uptr->u3 = (int32)*data;
           CLR_BUF(uptr);
           dptr->flags &= ~(MTDF_BUFFUL|MTDF_STOP|MTDF_UNIT_MSK);
           dptr->flags |= (unit << MTDF_V_UNIT);
@@ -319,7 +319,6 @@ int mt_df10_fetch(DEVICE *dptr, int addr) {
 }
 
 int mt_df10_read(DEVICE *dptr, UNIT *uptr) {
-     uint64 data;
      if (dptr->flags & MTDF_TYPEB) {
          if (mt_wcr == 0) {
              if(!mt_df10_fetch(dptr, 0))
@@ -499,7 +498,7 @@ t_stat mt_srv(UNIT * uptr)
             uptr->u6 = 0;
             uptr->u5 = 0;
         }
-        if (uptr->u6 < uptr->hwmark) {
+        if ((uint32)uptr->u6 < uptr->hwmark) {
             int cc = (8 * (3 - uptr->u5)) + 4;
             uint8 ch;
             if ((cmd & 07) == CMP && uptr->u5 == 0) {
@@ -688,7 +687,6 @@ t_stat mt_srv(UNIT * uptr)
 
 void mt_read_word(UNIT *uptr) {
      int i, cc, ch;
-     uint64 buf;
    
      buf_reg = 0;
      for(i = 0; i <= 4; i++) {
@@ -729,7 +727,7 @@ mt_boot(int32 unit_num, DEVICE * dptr)
     while (wc != 0) {
         wc = (wc + 1) & RMASK;
         addr = (addr + 1) & RMASK;
-        if (uptr->u6 >= reclen) {
+        if ((uint32)uptr->u6 >= reclen) {
             r = sim_tape_rdrecf(uptr, &mt_buffer[0], &reclen, BUFFSIZE);
             if (r != SCPE_OK)
                 return r;
diff --git a/PDP10/ka10_pt.c b/PDP10/ka10_pt.c
index 3c08c4c..c45c41b 100644
--- a/PDP10/ka10_pt.c
+++ b/PDP10/ka10_pt.c
@@ -46,7 +46,6 @@
 #define TAPE_PR     000400
 
 
-DEVICE         ptp_dev;
 t_stat         ptp_devio(uint32 dev, uint64 *data);
 t_stat         ptp_svc (UNIT *uptr);
 t_stat         ptp_reset (DEVICE *dptr);
@@ -56,7 +55,6 @@ t_stat         ptp_help (FILE *st, DEVICE *dptr, UNIT *uptr,
                             int32 flag, const char *cptr);
 const char    *ptp_description (DEVICE *dptr);
              
-DEVICE         ptr_dev;
 t_stat         ptr_devio(uint32 dev, uint64 *data);
 t_stat         ptr_svc (UNIT *uptr);
 t_stat         ptr_reset (DEVICE *dptr);
@@ -166,8 +164,6 @@ t_stat ptp_devio(uint32 dev, uint64 *data) {
 /* Unit service */
 t_stat ptp_svc (UNIT *uptr)
 {
-    t_stat r;
-    char c;
     uptr->STATUS &= ~BUSY_FLG;
     uptr->STATUS |= DONE_FLG;
     set_interrupt(PP_DEVNUM, uptr->STATUS & 7);
@@ -292,7 +288,7 @@ t_stat ptr_svc (UNIT *uptr)
            count--;
         } 
     }
-    uptr->CHL = (word >> 18);
+    uptr->CHL = (word >> 18) & 0777777;
     uptr->CHR = word & 0777777;
     return SCPE_OK;
 }
diff --git a/PDP10/ka10_rc.c b/PDP10/ka10_rc.c
index f59b5f5..28c731e 100644
--- a/PDP10/ka10_rc.c
+++ b/PDP10/ka10_rc.c
@@ -194,13 +194,11 @@ DEVICE *rc_devs[] = {
 
 
 t_stat rc_devio(uint32 dev, uint64 *data) {
-     uint64       res;
      int          ctlr = (dev - RC_DEVNUM) >> 2;
      struct df10 *df10 = &rc_df10[ctlr];
      UNIT        *uptr;
      DEVICE      *dptr;
      int          unit;
-     int          cyl;
      int          tmp;
      int          drv;
 
@@ -443,7 +441,6 @@ rc_boot(int32 unit_num, DEVICE * dptr)
 {
     UNIT               *uptr = &dptr->units[unit_num];
     int                 dtype = GET_DTYPE(uptr->flags);
-    uint64              buf_reg;
     uint32              addr;
     int                 wc;
     int                 wps;
@@ -470,7 +467,6 @@ rc_boot(int32 unit_num, DEVICE * dptr)
 
 t_stat rc_attach (UNIT *uptr, CONST char *cptr)
 {
-int32 drv, i, p;
 t_stat r;
 
 uptr->capac = rc_drv_tab[GET_DTYPE (uptr->flags)].size;
@@ -486,8 +482,6 @@ return SCPE_OK;
 
 t_stat rc_detach (UNIT *uptr)
 {
-int32 drv;
-
 if (!(uptr->flags & UNIT_ATT))                          /* attached? */
     return SCPE_OK;
 if (sim_is_active (uptr))                              /* unit active? */
diff --git a/PDP10/ka10_rp.c b/PDP10/ka10_rp.c
index 3f27b97..01f9f6f 100644
--- a/PDP10/ka10_rp.c
+++ b/PDP10/ka10_rp.c
@@ -457,8 +457,6 @@ t_stat rp_devio(uint32 dev, uint64 *data) {
      int            ctlr = -1;
      DEVICE        *dptr;
      struct df10   *df10;
-     UNIT          *uptr;
-     int            tmp;
      int            drive;
 
      for (drive = 0; drive < NUM_DEVS_RP; drive++) {
@@ -578,6 +576,7 @@ t_stat rp_devio(uint32 dev, uint64 *data) {
          }
          return SCPE_OK;
     }
+    return SCPE_OK; /* Unreached */
 }
 
 
@@ -754,7 +753,7 @@ t_stat rp_svc (UNIT *uptr)
     struct df10 *df;
     int          cyl = uptr->u4 & 01777;
     int          diff, da;
-    t_stat       err, r;
+    t_stat       r;
 
     /* Find dptr, and df10 */
     for (ctlr = 0; ctlr < NUM_DEVS_RP; ctlr++) {
@@ -991,7 +990,6 @@ rp_boot(int32 unit_num, DEVICE * rptr)
     UNIT               *uptr = &rptr->units[unit_num];
     uint32              addr;
     uint32              ptr;
-    int                 sect;
     int                 wc;
 
     sim_fseek(uptr->fileref, 0, SEEK_SET);
@@ -1011,7 +1009,6 @@ rp_boot(int32 unit_num, DEVICE * rptr)
 
 t_stat rp_attach (UNIT *uptr, CONST char *cptr)
 {
-    int32 drv, i, p;
     t_stat r;
     DEVICE *rptr;
     DIB *dib;
@@ -1040,8 +1037,6 @@ t_stat rp_attach (UNIT *uptr, CONST char *cptr)
 
 t_stat rp_detach (UNIT *uptr)
 {
-    int32 drv;
-
     if (!(uptr->flags & UNIT_ATT))                          /* attached? */
         return SCPE_OK;
     if (sim_is_active (uptr))                              /* unit active? */
diff --git a/PDP10/ka10_sys.c b/PDP10/ka10_sys.c
index 4828192..5589553 100644
--- a/PDP10/ka10_sys.c
+++ b/PDP10/ka10_sys.c
@@ -136,7 +136,7 @@ DEBTAB              dev_debug[] = {
 #define EXE_DIR 01776                                   /* EXE directory */
 #define EXE_VEC 01775                                   /* EXE entry vec */
 #define EXE_PDV 01774                                   /* EXE ignored */
-#define EXE_END 01777                                   /* EXE end
+#define EXE_END 01777                                   /* EXE end */
 
 /* RIM10 loader
 
@@ -152,6 +152,7 @@ DEBTAB              dev_debug[] = {
         JRST start
 */
 
+#define RIM_EOF 0xFFFFFFFFFFFFFFFFLL
 uint64 getrimw (FILE *fileref)
 {
 int32 i, tmp;
@@ -160,7 +161,7 @@ uint64 word;
 word = 0;
 for (i = 0; i < 6;) {
     if ((tmp = getc (fileref)) == EOF)
-        return -1;
+        return RIM_EOF;
     if (tmp & 0200) {
         word = (word << 6) | ((uint64) tmp & 077);
         i++;
@@ -178,19 +179,19 @@ int32 op;
 
 for ( ;; ) {                                            /* loop until JRST */
     count = cksm = getrimw (fileref);                   /* get header */
-    if (count < 0)                                      /* read err? */
+    if (count == RIM_EOF)                                      /* read err? */
         return SCPE_FMT;
     if (TSTS (count)) {                                 /* hdr = IOWD? */
         for ( ; TSTS (count); count = AOB (count)) {
             data = getrimw (fileref);                   /* get data wd */
-            if (data < 0)
+            if (data == RIM_EOF)
                 return SCPE_FMT;
             cksm = cksm + data;                         /* add to cksm */
             pa = ((uint32) count + 1) & RMASK;             /* store */
             M[pa] = data;
             }                                           /* end for */
         data = getrimw (fileref);                       /* get cksm */
-        if (data < 0)
+        if (data == RIM_EOF)
             return SCPE_FMT;
         if ((cksm + data) & FMASK)                      /* test cksm */
             return SCPE_CSUM;
@@ -237,9 +238,9 @@ int get_word(FILE *fileref, uint64 *word)
 
 t_stat load_sav (FILE *fileref)
 {
-    uint64 count, data;
+    uint64 data;
     uint32 pa;
-    int32 wc, op;
+    int32 wc;
 
     for ( ;; ) {                                        /* loop */
         if (get_word(fileref, &data))