diff --git a/PDP10/ks10_dup.c b/PDP10/ks10_dup.c
index 22ee7ab..d65b099 100644
--- a/PDP10/ks10_dup.c
+++ b/PDP10/ks10_dup.c
@@ -874,7 +874,7 @@ if (!tmxr_tpbusyln(&dup_ldsc[dup])) {  /* Not Busy sending? */
         dup_xmtpacket[dup] = (uint8 *)realloc (dup_xmtpacket[dup], dup_xmtpksize[dup]);
         }
     /* Strip sync bytes at the beginning of a message */
-    while (len && (dup_xmtpkoffset[dup] == 0) && (bytes[0] == DDCMP_SYN)) {
+    while (len > 0 && (dup_xmtpkoffset[dup] == 0) && (bytes[0] == DDCMP_SYN)) {
         --len;
         ++bytes;
         }
diff --git a/PDP10/ks10_dz.c b/PDP10/ks10_dz.c
index d5877bf..6945e05 100644
--- a/PDP10/ks10_dz.c
+++ b/PDP10/ks10_dz.c
@@ -443,7 +443,6 @@ t_stat dz_svc (UNIT *uptr)
 void
 dz_checkirq(struct pdp_dib   *dibp)
 {
-    int        j;
     int        i;
     int        ln;
     int        stop;
diff --git a/PDP10/ks10_kmc.c b/PDP10/ks10_kmc.c
index deeb4b9..ed879c7 100644
--- a/PDP10/ks10_kmc.c
+++ b/PDP10/ks10_kmc.c
@@ -343,13 +343,6 @@ static DEBTAB kmc_debug[] = {
     {0}
 };
 
-/* These count the total pending interrupts for each vector
- * across all KMCs.
- */
-
-static int32 AintPending = 0;
-static int32 BintPending = 0;
-
 /* Per-KMC state */
 
 /* To help make the code more readable, by convention the symbol 'k'
@@ -757,8 +750,8 @@ static t_stat kmc_reset(DEVICE* dptr) {
             sel2 = 0xa5a5;
             sel4 = 0xdead;
             sel6 = 0x5a5a;
-            memset (ucode, 0xcc, sizeof ucode);
-            memset (dram, 0xdd, sizeof dram);
+            memset ((uint8 *)&ucode[0], 0xcc, sizeof ucode);
+            memset ((uint8 *)&dram[0], 0xdd, sizeof dram);
             gflags |= FLG_INIT;
             gflags &= ~FLG_UCINI;
             sim_register_internal_device (&kmc_int_rxdev);
@@ -1302,7 +1295,7 @@ static t_stat kmc_rxService (UNIT *rxup) {
     dupstate *d = line2dup[rxup->unit_line];
     BDL *bdl;
     t_stat r;
-    uint16 xrem, seglen;
+    uint16 seglen;
     int    i;
     t_addr ba;
 
@@ -2474,7 +2467,6 @@ static t_bool kmc_bufferAddressOut (int32 k, uint16 flags, uint16 rx, uint8 line
  */
 
 static int32 kmc_updateBDCount(uint32 bda, uint16 *bd) {
-  int  i;
   bda+=2;
   if (uba_write_npr_word(bda, kmc_dib.uba_ctl, bd[1]) == 0) {
      return 1;
diff --git a/PDP10/ks10_lp.c b/PDP10/ks10_lp.c
index 4f143bb..1ecbe28 100644
--- a/PDP10/ks10_lp.c
+++ b/PDP10/ks10_lp.c
@@ -116,7 +116,7 @@
 int             lp20_write(DEVICE *dptr, t_addr addr, uint16 data, int32 access);
 int             lp20_read(DEVICE *dptr, t_addr addr, uint16 *data, int32 access);
 void            lp20_printline(UNIT *uptr, int nl);
-void            lp20_output(UNIT *uptr, char c);
+void            lp20_output(UNIT *uptr, uint8 c);
 void            lp20_update_chkirq (UNIT *uptr, int done, int irq);
 void            lp20_update_ready(UNIT *uptr, uint16 setrdy, uint16 clrrdy);
 t_stat          lp20_svc (UNIT *uptr);
@@ -138,7 +138,7 @@ uint32          lp20_ba;
 uint16          lp20_wcnt;
 uint8           lp20_col;
 uint8           lp20_chksum;
-uint16          lp20_buf;
+uint8           lp20_buf;
 uint8           lp20_data;
 int             lp20_odd = 0;
 int             lp20_duvfa_state = 0;
@@ -285,7 +285,6 @@ int
 lp20_write(DEVICE *dptr, t_addr addr, uint16 data, int32 access)
 {
     struct pdp_dib   *dibp = (DIB *)dptr->ctxt;
-    int               base;
     uint16            temp;
 
     addr &= dibp->uba_mask;
@@ -401,7 +400,6 @@ int
 lp20_read(DEVICE *dptr, t_addr addr, uint16 *data, int32 access)
 {
     struct pdp_dib   *dibp = (DIB *)dptr->ctxt;
-    int               base;
     uint16            temp;
     int               par;
 
@@ -432,7 +430,7 @@ lp20_read(DEVICE *dptr, t_addr addr, uint16 *data, int32 access)
             break;
 
      case 012: /* LPRDAT */
-            temp = lp20_ram[lp20_buf] & 07777;
+            temp = lp20_ram[(int)lp20_buf] & 07777;
             par = (temp >> 8) ^ (temp >> 4) ^ temp;
             par = (par >> 2) ^ par;
             par ^= par >> 1;
@@ -442,7 +440,7 @@ lp20_read(DEVICE *dptr, t_addr addr, uint16 *data, int32 access)
 
      case 014: /* LPCOL/LPCBUF */
             *data = ((uint16)lp20_col) << 8;
-            *data |= lp20_buf;
+            *data |= (uint16)lp20_buf;
             break;
 
      case 016: /* LPCSUM/LPPDAT */
@@ -496,7 +494,7 @@ lp20_printline(UNIT *uptr, int nl) {
 
 /* Unit service */
 void
-lp20_output(UNIT *uptr, char c) {
+lp20_output(UNIT *uptr, uint8 c) {
 
     if (c == 0)
        return;
@@ -588,7 +586,6 @@ lp20_svc (UNIT *uptr)
     char            ch;
     int             fnc = (lp20_cs1 >> CS1_V_FNC) & CS1_M_FNC;
     uint16          ram_ch;
-    uint16          par;
     uint8           data;
 
     if (fnc == FNC_PRINT && (uptr->flags & UNIT_ATT) == 0) {
@@ -607,13 +604,13 @@ lp20_svc (UNIT *uptr)
         return SCPE_OK;
     }
 
-    lp20_buf = (uint16)(data & 0377);
+    lp20_buf = data;
     lp20_ba = (lp20_ba + 1) & 0777777;
     lp20_wcnt = (lp20_wcnt + 1) & 07777;
     if (lp20_wcnt == 0) {
         lp20_cs1 &= ~CS1_GO;
     }
-    lp20_chksum += (uint8)(lp20_buf & 0377);
+    lp20_chksum += lp20_buf;
     sim_debug(DEBUG_DETAIL, &lp20_dev, "LP npr %08o %06o %03o %d\n", lp20_ba, lp20_wcnt,
               lp20_buf, fnc);
     switch(fnc) {
@@ -633,7 +630,7 @@ lp20_svc (UNIT *uptr)
         }
         /* Check if translate flag set */
         if (ram_ch & LP20_RAM_TRN) {
-            lp20_buf = ram_ch & 0377;
+            lp20_buf = (uint8)(ram_ch & 0377);
         }
         /* Check if paper motion */
         if (ram_ch & LP20_RAM_PI) {
diff --git a/PDP10/ks10_uba.c b/PDP10/ks10_uba.c
index 5bb8b0d..c01cd53 100644
--- a/PDP10/ks10_uba.c
+++ b/PDP10/ks10_uba.c
@@ -364,13 +364,7 @@ uba_set_irq(DIB *dibp, int vect)
 void
 uba_clr_irq(DIB *idev, int vect)
 {
-    DEVICE *dptr;
     int     ubm = uba_device[idev->uba_ctl];
-    int     pi;
-    int     i;
-    int     j;
-    int     lvl;
-    int     high = 0;
 
     if (ubm < 0)
        return;
@@ -383,7 +377,6 @@ uba_clr_irq(DIB *idev, int vect)
 void
 uba_reset()
 {
-    DEVICE *dptr;
     int     i;
 
     /* Clear the Unibus map */