diff --git a/I7094/i7094_dsk.c b/I7094/i7094_dsk.c
index 710725f1..4c605c81 100644
--- a/I7094/i7094_dsk.c
+++ b/I7094/i7094_dsk.c
@@ -1151,9 +1151,9 @@ if (uptr == NULL)
 if ((uptr->flags & UNIT_ATT) == 0)
     return SCPE_UNATT;
 dptr = find_dev_from_unit (uptr);
-u = uptr - dptr->units;
 if (dptr == NULL)
     return SCPE_IERR;
+u = uptr - dptr->units;
 
 dtyp = GET_DTYPE (uptr->flags);
 if ((dtyp == TYPE_7320) || (dtyp == TYPE_1301))
diff --git a/PDP11/pdp11_xq.c b/PDP11/pdp11_xq.c
index e9a05ae4..ba1ff031 100644
--- a/PDP11/pdp11_xq.c
+++ b/PDP11/pdp11_xq.c
@@ -1132,7 +1132,6 @@ t_stat xq_process_setup(CTLR* xq)
   int i,j;
   int count = 0;
   float secs;
-  t_stat status;
   uint32 saved_debug = xq->dev->dctrl;
   ETH_MAC zeros = {0, 0, 0, 0, 0, 0};
   ETH_MAC filters[XQ_FILTER_MAX + 1];
@@ -1225,11 +1224,11 @@ t_stat xq_process_setup(CTLR* xq)
   for (i = 0; i < XQ_FILTER_MAX; i++)
     if (memcmp(zeros, &xq->var->setup.macs[i], sizeof(ETH_MAC)))
       memcpy (filters[count++], xq->var->setup.macs[i], sizeof(ETH_MAC));
-  status = eth_filter (xq->var->etherface, count, filters, xq->var->setup.multicast, xq->var->setup.promiscuous);
+  eth_filter (xq->var->etherface, count, filters, xq->var->setup.multicast, xq->var->setup.promiscuous);
 
   /* process MOP information */
   if (xq->var->write_buffer.msg[0])
-    status = xq_process_mop(xq);
+    xq_process_mop(xq);
 
   /* mark setup block valid */
   xq->var->setup.valid = 1;
@@ -1366,7 +1365,6 @@ t_stat xq_dispatch_rbdl(CTLR* xq)
 {
   int i;
   int32 rstatus, wstatus;
-  t_stat status;
 
   sim_debug(DBG_TRC, xq->dev, "xq_dispatch_rbdl()\n");
 
@@ -1394,7 +1392,7 @@ t_stat xq_dispatch_rbdl(CTLR* xq)
 
   /* process any waiting packets in receive queue */
   if (xq->var->ReadQ.count)
-    status = xq_process_rbdl(xq);
+    xq_process_rbdl(xq);
 
   return SCPE_OK;
 }
@@ -2250,7 +2248,6 @@ t_stat xq_wr_icr(CTLR* xq, int32 data)
 
 t_stat xq_wr(int32 data, int32 PA, int32 access)
 {
-  t_stat status;
   CTLR* xq = xq_pa2ctlr(PA);
   int index = (PA >> 1) & 07;   /* word index */
 
@@ -2266,19 +2263,19 @@ t_stat xq_wr(int32 data, int32 PA, int32 access)
           xq->var->iba = (xq->var->iba & 0xFFFF) | ((data & 0xFFFF) << 16);
           break;
         case 2:   /* ICR */
-          status = xq_wr_icr(xq, data);
+          xq_wr_icr(xq, data);
           break;
         case 3:
           break;
         case 4:   /* SRQR */
-          status = xq_wr_srqr(xq, data);
+          xq_wr_srqr(xq, data);
           break;
         case 5:
           break;
         case 6:
           break;
         case 7:   /* ARQR */
-          status = xq_wr_arqr(xq, data);
+          xq_wr_arqr(xq, data);
           break;
       }
       break;
@@ -2304,20 +2301,20 @@ t_stat xq_wr(int32 data, int32 PA, int32 access)
           break;
         case 3:   /* receive bdl high bits */
           xq->var->rbdl[1] = data;
-          status = xq_dispatch_rbdl(xq); /* start receive operation */
+          xq_dispatch_rbdl(xq); /* start receive operation */
           break;
         case 4:   /* transmit bdl low bits */
           xq->var->xbdl[0] = data;
           break;
         case 5:   /* transmit bdl high bits */
           xq->var->xbdl[1] = data;
-          status = xq_dispatch_xbdl(xq); /* start transmit operation */
+          xq_dispatch_xbdl(xq); /* start transmit operation */
           break;
         case 6:   /* vector address register */
-          status = xq_wr_var(xq, data);
+          xq_wr_var(xq, data);
           break;
         case 7:   /* control and status register */
-          status = xq_wr_csr(xq, data);
+          xq_wr_csr(xq, data);
           break;
       }
       break;
diff --git a/PDP11/pdp11_xu.c b/PDP11/pdp11_xu.c
index 28dc50e0..f9cda450 100644
--- a/PDP11/pdp11_xu.c
+++ b/PDP11/pdp11_xu.c
@@ -553,7 +553,6 @@ t_stat xu_system_id (CTLR* xu, const ETH_MAC dest, uint16 receipt_id)
 t_stat xu_svc(UNIT* uptr)
 {
   int queue_size;
-  t_stat status;
   CTLR* xu = xu_unit2ctlr(uptr);
   const ETH_MAC mop_multicast = {0xAB, 0x00, 0x00, 0x02, 0x00, 0x00};
   const int one_second = clk_tps * tmr_poll;
@@ -568,7 +567,7 @@ t_stat xu_svc(UNIT* uptr)
     {
     queue_size = xu->var->ReadQ.count;
     /* read a packet from the ethernet - processing is via the callback */
-    status = eth_read (xu->var->etherface, &xu->var->read_buffer, xu->var->rcallback);
+    eth_read (xu->var->etherface, &xu->var->read_buffer, xu->var->rcallback);
   } while (queue_size != xu->var->ReadQ.count);
 
   /* Now pump any still queued packets into the system */
@@ -578,7 +577,7 @@ t_stat xu_svc(UNIT* uptr)
   /* send identity packet when timer expires */
   if (--xu->var->idtmr <= 0) {
     if ((xu->var->mode & MODE_DMNT) == 0)           /* if maint msg is not disabled */
-      status = xu_system_id(xu, mop_multicast, 0);  /*   then send ID packet */
+      xu_system_id(xu, mop_multicast, 0);           /*   then send ID packet */
     xu->var->idtmr = XU_ID_TIMER_VAL * one_second;  /* reset timer */
   }
 
@@ -627,7 +626,6 @@ void xu_setclrint(CTLR* xu, int32 bits)
 
 t_stat xu_sw_reset (CTLR* xu)
 {
-  t_stat status;
   int i;
 
   sim_debug(DBG_TRC, xu->dev, "xu_sw_reset()\n");
@@ -668,9 +666,9 @@ t_stat xu_sw_reset (CTLR* xu)
     xu->var->setup.macs[1][i] = 0xff; /* Broadcast Address */
   xu->var->setup.mac_count = 2;
   if (xu->var->etherface)
-    status = eth_filter (xu->var->etherface, xu->var->setup.mac_count,
-                         xu->var->setup.macs, xu->var->setup.multicast,
-                         xu->var->setup.promiscuous);
+    eth_filter (xu->var->etherface, xu->var->setup.mac_count,
+                xu->var->setup.macs, xu->var->setup.multicast,
+                xu->var->setup.promiscuous);
 
   /* activate device if not disabled */
   if ((xu->dev->flags & DEV_DIS) == 0) {
@@ -708,7 +706,7 @@ int32 xu_command(CTLR* xu)
   uint32 udbb;
   int fnc, mtlen, i, j;
   uint16 value, pltlen;
-  t_stat status, rstatus, wstatus, wstatus2, wstatus3;
+  t_stat rstatus, wstatus, wstatus2, wstatus3;
   struct xu_stats* stats = &xu->var->stats;
   uint16* udb = xu->var->udb;
   uint16* mac_w = (uint16*) xu->var->mac;
@@ -795,9 +793,9 @@ int32 xu_command(CTLR* xu)
       rstatus = Map_ReadB(udbb, mtlen * 6, (uint8*) &xu->var->setup.macs[2]);
       if (rstatus == 0) {
         xu->var->setup.mac_count = mtlen + 2;
-        status = eth_filter (xu->var->etherface, xu->var->setup.mac_count,
-                             xu->var->setup.macs, xu->var->setup.multicast,
-                             xu->var->setup.promiscuous);
+        eth_filter (xu->var->etherface, xu->var->setup.mac_count,
+                    xu->var->setup.macs, xu->var->setup.multicast,
+                    xu->var->setup.promiscuous);
       } else {
         xu->var->pcsr0 |= PCSR0_PCEI;
       }
@@ -922,9 +920,9 @@ int32 xu_command(CTLR* xu)
 
       /* if promiscuous or multicast flags changed, change filter */
       if ((value ^ xu->var->mode) & (MODE_PROM | MODE_ENAL))
-        status = eth_filter (xu->var->etherface, xu->var->setup.mac_count,
-                             xu->var->setup.macs, xu->var->setup.multicast,
-                             xu->var->setup.promiscuous);
+        eth_filter (xu->var->etherface, xu->var->setup.mac_count,
+                    xu->var->setup.macs, xu->var->setup.multicast,
+                    xu->var->setup.promiscuous);
       break;
 
     case FC_RSTAT:			/* read extended status */
@@ -1339,7 +1337,6 @@ void xu_port_command (CTLR* xu)
   char* msg;
   int command = xu->var->pcsr0 & PCSR0_PCMD;
   int state = xu->var->pcsr1 & PCSR1_STATE;
-  int bits;
   static char* commands[] = {
       "NO-OP",
       "GET PCBB",
@@ -1368,7 +1365,7 @@ void xu_port_command (CTLR* xu)
       break;
 
     case CMD_GETCMD:		/* GET COMMAND */
-      bits = xu_command(xu);
+      xu_command(xu);
       xu->var->pcsr0 |= PCSR0_DNI;
       break;
 
@@ -1606,12 +1603,11 @@ t_stat xu_attach(UNIT* uptr, char* cptr)
 
 t_stat xu_detach(UNIT* uptr)
 {
-  t_stat status;
   CTLR* xu = xu_unit2ctlr(uptr);
   sim_debug(DBG_TRC, xu->dev, "xu_detach()\n");
 
   if (uptr->flags & UNIT_ATT) {
-    status = eth_close (xu->var->etherface);
+    eth_close (xu->var->etherface);
     free(xu->var->etherface);
     xu->var->etherface = 0;
     free(uptr->filename);
diff --git a/PDP18B/pdp18b_cpu.c b/PDP18B/pdp18b_cpu.c
index 9545390e..4e5a53b0 100644
--- a/PDP18B/pdp18b_cpu.c
+++ b/PDP18B/pdp18b_cpu.c
@@ -2132,7 +2132,7 @@ if (usmd && (sw & SWMASK ('V'))) {
         addr = RelocXVM (addr, REL_C);
     else if (RELOC)
         addr = Reloc15 (addr, REL_C);
-    if ((int32) addr < 0)
+    if (((int32)addr) < 0)
         return STOP_MME;
     }
 #endif
@@ -2153,7 +2153,7 @@ if (usmd && (sw & SWMASK ('V'))) {
         addr = RelocXVM (addr, REL_C);
     else if (RELOC)
         addr = Reloc15 (addr, REL_C);
-    if ((int32) addr < 0)
+    if (((int32)addr) < 0)
         return STOP_MME;
     }
 #endif
diff --git a/scp.c b/scp.c
index eac6523a..f61abf70 100644
--- a/scp.c
+++ b/scp.c
@@ -3991,8 +3991,6 @@ if (!initialized) {
         }
     }
 if (prompt) {                                           /* interactive? */
-    char *tmpc;
-
     if (p_readline) {
         char *tmpc = p_readline (prompt);               /* get cmd line */
         if (tmpc == NULL)                               /* bad result? */
diff --git a/sim_console.c b/sim_console.c
index 3bffbf42..200749bc 100644
--- a/sim_console.c
+++ b/sim_console.c
@@ -385,13 +385,11 @@ return SCPE_OK;
 
 t_stat sim_set_deboff (int32 flag, char *cptr)
 {
-t_stat r;
-
 if (cptr && (*cptr != 0))                               /* now eol? */
     return SCPE_2MARG;
 if (sim_deb == NULL)                                    /* no log? */
     return SCPE_OK;
-r = sim_close_logfile (&sim_deb_ref);
+sim_close_logfile (&sim_deb_ref);
 sim_deb = NULL;
 if (!sim_quiet)
     printf ("Debug output disabled\n");
diff --git a/sim_disk.c b/sim_disk.c
index 99f9d088..49a97a2b 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -1024,12 +1024,12 @@ t_stat sim_disk_detach (UNIT *uptr)
 {
 struct disk_context *ctx = (struct disk_context *)uptr->disk_ctx;
 int (*close_function)(FILE *f);
-FILE *fileref = uptr->fileref;
-DEVICE *dptr;
+FILE *fileref;
 t_bool auto_format;
 
 if (uptr == NULL)
     return SCPE_IERR;
+fileref = uptr->fileref;
 switch (DK_GET_FMT (uptr)) {                            /* case on format */
     case DKUF_F_STD:                                    /* Simh */
         close_function = fclose;
@@ -1045,7 +1045,7 @@ if (!(uptr->flags & UNIT_ATTABLE))                      /* attachable? */
     return SCPE_NOATT;
 if (!(uptr->flags & UNIT_ATT))                          /* attached? */
     return SCPE_OK;
-if ((dptr = find_dev_from_unit (uptr)) == NULL)
+if (NULL == find_dev_from_unit (uptr))
     return SCPE_OK;
 auto_format = ctx->auto_format;