diff --git a/PDP11/pdp11_hk.c b/PDP11/pdp11_hk.c
index 25d978b9..cb1c07b0 100644
--- a/PDP11/pdp11_hk.c
+++ b/PDP11/pdp11_hk.c
@@ -1073,7 +1073,7 @@ t_stat hk_svc (UNIT *uptr)
 {
 int32 i, t, dc, fnc;
 t_seccnt sectsread;
-t_stat err;
+t_stat err = 0;
 int32 wc, awc, da;
 uint32 drv, ba;
 uint16 comp;
diff --git a/PDP11/pdp11_io_lib.c b/PDP11/pdp11_io_lib.c
index a798086e..d6ee7161 100644
--- a/PDP11/pdp11_io_lib.c
+++ b/PDP11/pdp11_io_lib.c
@@ -879,11 +879,9 @@ AUTO_CON auto_tab[] = {/*c  #v  am vm  fxa   fxv */
 
 static void build_vector_tab (void)
 {
-int32 ilvl, ibit;
 static t_bool done = FALSE;
 AUTO_CON *autp;
 DEVICE *dptr;
-DIB *dibp;
 uint32 j, k;
 
 if (done)
@@ -895,10 +893,13 @@ for (j = 0; (dptr = sim_devices[j]) != NULL; j++) {
     for (autp = auto_tab; autp->valid >= 0; autp++) {
         for (k=0; autp->dnam[k]; k++) {
             if (!strcmp(dptr->name, autp->dnam[k])) {
+#if (VEC_SET != 0)
+                int32 ilvl, ibit;
+                DIB *dibp;
+
                 dibp = (DIB *)dptr->ctxt;
                 ilvl = dibp->vloc / 32;
                 ibit = dibp->vloc % 32;
-#if (VEC_SET != 0)
                 if (1) {
                     int v;
                     
@@ -918,7 +919,7 @@ t_stat auto_config (const char *name, int32 nctrl)
 {
 uint32 csr = IOPAGEBASE + AUTO_CSRBASE;
 uint32 vec = AUTO_VECBASE;
-int32 ilvl, ibit, numc;
+int32 numc;
 AUTO_CON *autp;
 DEVICE *dptr;
 DIB *dibp;
@@ -962,8 +963,6 @@ for (autp = auto_tab; autp->valid >= 0; autp++) {       /* loop thru table */
         if (dibp == NULL)                               /* not there??? */
             return SCPE_IERR;
         numc = dibp->numc ? dibp->numc : 1;
-        ilvl = dibp->vloc / 32;
-        ibit = dibp->vloc % 32;
         /* Identify how many devices earlier in the device list are 
            enabled and use that info to determine fixed address assignments */
         for (k=jena=0; k<j; k++) {
diff --git a/PDP11/pdp11_pclk.c b/PDP11/pdp11_pclk.c
index ee925b86..8905af6a 100644
--- a/PDP11/pdp11_pclk.c
+++ b/PDP11/pdp11_pclk.c
@@ -371,10 +371,7 @@ return val;
 
 t_stat pclk_svc (UNIT *uptr)
 {
-int32 rv;
-
 sim_debug (DBG_TICK, &pclk_dev, "pclk_svc()\n");
-rv = CSR_GETRATE (pclk_csr);                            /* get rate */
 if (pclk_csr & CSR_DONE)                                /* done already set? */
     pclk_csr = pclk_csr | CSR_ERR;                      /* set error */
 else
diff --git a/PDP11/pdp11_rl.c b/PDP11/pdp11_rl.c
index 51c0d11c..cd403f93 100644
--- a/PDP11/pdp11_rl.c
+++ b/PDP11/pdp11_rl.c
@@ -1069,8 +1069,6 @@ return SCPE_OK;
 
 t_stat rl_set_type (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
 {
-int32 dtype = GET_DTYPE (val);
-
 if ((val < 0) || (cptr && *cptr))
     return SCPE_ARG;
 if (uptr->flags & UNIT_ATT)
diff --git a/PDP11/pdp11_rp.c b/PDP11/pdp11_rp.c
index 6b6c16b4..43aefe3a 100644
--- a/PDP11/pdp11_rp.c
+++ b/PDP11/pdp11_rp.c
@@ -1391,8 +1391,6 @@ return sim_disk_detach (uptr);
 
 t_stat rp_set_type (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
 {
-int32 dtype = GET_DTYPE (val);
-
 if ((val < 0) || (cptr && *cptr))
     return SCPE_ARG;
 if (uptr->flags & UNIT_ATT)
diff --git a/PDP11/pdp11_rq.c b/PDP11/pdp11_rq.c
index 04658891..be6331e8 100644
--- a/PDP11/pdp11_rq.c
+++ b/PDP11/pdp11_rq.c
@@ -2874,7 +2874,6 @@ return SCPE_OK;
 
 t_stat rq_set_plug (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
 {
-MSC *cp = rq_ctxmap[uptr->cnum];
 int32 plug;
 uint32 i;
 t_stat r;
diff --git a/PDP11/pdp11_td.c b/PDP11/pdp11_td.c
index 71d0fe96..8727aec0 100644
--- a/PDP11/pdp11_td.c
+++ b/PDP11/pdp11_td.c
@@ -607,8 +607,6 @@ static int32 td_ctime = 150;                            /* command time */
 static int32 td_xtime = 180;                            /* tr set time */
 static int32 td_itime = 180;                            /* init time */
 
-static int32 td_regval;                                 /* temp location used in reg declarations */
-
 static int32 td_ctrls = 1;                              /* number of enabled controllers */
 
 static uint32 tdi_ireq = 0;
diff --git a/PDP11/pdp11_vh.c b/PDP11/pdp11_vh.c
index efd2b6d0..99855bac 100644
--- a/PDP11/pdp11_vh.c
+++ b/PDP11/pdp11_vh.c
@@ -835,8 +835,6 @@ return TX_FIFO_SIZE - lp->txfifo_cnt;
 static int32 tx_fifo_put ( TMLX    *lp,
             int32   data    )
 {
-    int32   status = 0;
-
     if (tx_fifo_free_count (lp) == 0)
         return -1;
     lp->txfifo[(lp->txfifo_idx + lp->txfifo_cnt) % TX_FIFO_SIZE] = data;
diff --git a/PDP11/pdp11_xq.c b/PDP11/pdp11_xq.c
index 39a610cb..0ea6dc5a 100644
--- a/PDP11/pdp11_xq.c
+++ b/PDP11/pdp11_xq.c
@@ -1313,7 +1313,7 @@ t_stat xq_process_mop(CTLR* xq)
     return SCPE_NOFNC;
 
   while ((meb->type != 0) && (meb < limit)) {
-    address = (meb->add_hi << 16) || (meb->add_mi << 8) || meb->add_lo;
+    address = (meb->add_hi << 16) | (meb->add_mi << 8) | meb->add_lo;
 
     /* MOP stuff here - NOT YET FULLY IMPLEMENTED */
     sim_debug (DBG_WRN, xq->dev, "Processing MEB type: %d\n", meb->type);
@@ -3147,7 +3147,6 @@ t_stat xq_boot (int32 unitno, DEVICE *dptr)
 {
 #ifdef VM_PDP11
 size_t i;
-DIB *dib = (DIB *)dptr->ctxt;
 extern int32 REGFILE[6][2];                 /* R0-R5, two sets */
 
 for (i = 0; i < BOOT_LEN; i++)
diff --git a/VAX/vax_cis.c b/VAX/vax_cis.c
index 473a44b8..99df93b1 100644
--- a/VAX/vax_cis.c
+++ b/VAX/vax_cis.c
@@ -1049,6 +1049,8 @@ switch (opc) {                                          /* case on opcode */
                     RSVD_OPND_FAULT(EDITPC);
                 pop = pop & ~EO_RPT_MASK;               /* isolate op */
                 }
+            else
+                rpt = 1;
             switch (pop) {                              /* case on op */
 
             case EO_END_FLOAT:                          /* end float */
@@ -1217,7 +1219,7 @@ return cc;
 
 int32 ReadDstr (int32 lnt, int32 adr, DSTR *src, int32 acc)
 {
-int32 c, i, end, t;
+int32 c, i, end, t = 0;
 
 *src = Dstr_zero;                                       /* clear result */
 end = lnt / 2;                                          /* last byte */