diff --git a/PDP11/pdp11_cis.c b/PDP11/pdp11_cis.c
index 9f78f1bd..fd0ef208 100644
--- a/PDP11/pdp11_cis.c
+++ b/PDP11/pdp11_cis.c
@@ -170,7 +170,7 @@ typedef struct {
     uint32              val[DSTRLNT];
     } DSTR;
 
-static DSTR Dstr0 = { 0, 0, 0, 0, 0 };
+static DSTR Dstr0 = { 0, {0, 0, 0, 0} };
 
 extern int32 isenable, dsenable;
 extern int32 N, Z, V, C, fpd, ipl;
@@ -327,8 +327,6 @@ static int32 binover[2][16] = {
     '0', '0', '0', '0', '0', '0'
     };
 
-static unsigned char movbuf[65536];
-
 /* CIS emulator */
 
 t_stat cis11 (int32 IR)
@@ -342,7 +340,7 @@ uint32 nc, digit, result;
 t_stat st;
 static DSTR accum, src1, src2, dst;
 static DSTR mptable[10];
-static DSTR Dstr1 = { 0, 0x10, 0, 0, 0 };
+static DSTR Dstr1 = { 0, {0x10, 0, 0, 0} };
 
 old_PC = (PC - 2) & 0177777;                            /* original PC */
 op = IR & 0177;                                         /* IR <6:0> */
diff --git a/PDP11/pdp11_cpu.c b/PDP11/pdp11_cpu.c
index 7f8eac70..65f0ec5e 100644
--- a/PDP11/pdp11_cpu.c
+++ b/PDP11/pdp11_cpu.c
@@ -256,7 +256,7 @@ typedef struct {
 extern FILE *sim_log;
 
 uint16 *M = NULL;                                       /* memory */
-int32 REGFILE[6][2] = { 0 };                            /* R0-R5, two sets */
+int32 REGFILE[6][2] = { {0} };                          /* R0-R5, two sets */
 int32 STACKFILE[4] = { 0 };                             /* SP, four modes */
 int32 saved_PC = 0;                                     /* program counter */
 int32 R[8] = { 0 };                                     /* working registers */
@@ -273,7 +273,7 @@ int32 trap_req = 0;                                     /* trap requests */
 int32 int_req[IPL_HLVL] = { 0 };                        /* interrupt requests */
 int32 PIRQ = 0;                                         /* programmed int req */
 int32 STKLIM = 0;                                       /* stack limit */
-fpac_t FR[6] = { 0 };                                   /* fp accumulators */
+fpac_t FR[6] = { {0} };                                 /* fp accumulators */
 int32 FPS = 0;                                          /* fp status */
 int32 FEC = 0;                                          /* fp exception code */
 int32 FEA = 0;                                          /* fp exception addr */
@@ -1246,7 +1246,7 @@ while (reason == 0)  {
                     else dst = R[dstspec];
                     }
                 else {
-                    i = ((cm == pm) && (cm == MD_USR))? calc_ds (pm): calc_is (pm);
+                    i = ((cm == pm) && (cm == MD_USR))? (int32)calc_ds (pm): (int32)calc_is (pm);
                     dst = ReadW ((GeteaW (dstspec) & 0177777) | i);
                     }
                 N = GET_SIGN_W (dst);
diff --git a/PDP11/pdp11_cpumod.c b/PDP11/pdp11_cpumod.c
index faf5a2b2..c74e96c9 100644
--- a/PDP11/pdp11_cpumod.c
+++ b/PDP11/pdp11_cpumod.c
@@ -1159,7 +1159,7 @@ if ((mc != 0) && !get_yn ("Really truncate memory [N]?", FALSE))
 nM = (uint16 *) calloc (val >> 1, sizeof (uint16));
 if (nM == NULL)
     return SCPE_MEM;
-clim = (((t_addr) val) < MEMSIZE)? val: MEMSIZE;
+clim = (((t_addr) val) < MEMSIZE)? (uint32)val: MEMSIZE;
 for (i = 0; i < clim; i = i + 2)
     nM[i >> 1] = M[i >> 1];
 free (M);
diff --git a/PDP11/pdp11_dc.c b/PDP11/pdp11_dc.c
index 1c653fe8..99eecf2d 100644
--- a/PDP11/pdp11_dc.c
+++ b/PDP11/pdp11_dc.c
@@ -86,7 +86,7 @@ uint32 dci_ireq = 0;
 uint16 dco_csr[DCX_LINES] = { 0 };                      /* control/status */
 uint8 dco_buf[DCX_LINES] = { 0 };
 uint32 dco_ireq = 0;
-TMLN dcx_ldsc[DCX_LINES] = { 0 };                       /* line descriptors */
+TMLN dcx_ldsc[DCX_LINES] = { {0} };                     /* line descriptors */
 TMXR dcx_desc = { DCX_LINES, 0, 0, dcx_ldsc };          /* mux descriptor */
 
 static const uint8 odd_par[] = {
diff --git a/PDP11/pdp11_dl.c b/PDP11/pdp11_dl.c
index ec8cc9ab..9b264667 100644
--- a/PDP11/pdp11_dl.c
+++ b/PDP11/pdp11_dl.c
@@ -87,7 +87,7 @@ uint32 dli_ireq[2] = { 0, 0};
 uint16 dlo_csr[DLX_LINES] = { 0 };                      /* control/status */
 uint8 dlo_buf[DLX_LINES] = { 0 };
 uint32 dlo_ireq = 0;
-TMLN dlx_ldsc[DLX_LINES] = { 0 };                       /* line descriptors */
+TMLN dlx_ldsc[DLX_LINES] = { {0} };                     /* line descriptors */
 TMXR dlx_desc = { DLX_LINES, 0, 0, dlx_ldsc };          /* mux descriptor */
 
 t_stat dlx_rd (int32 *data, int32 PA, int32 access);
diff --git a/PDP11/pdp11_rc.c b/PDP11/pdp11_rc.c
index 1f32ec59..f0bab9ba 100644
--- a/PDP11/pdp11_rc.c
+++ b/PDP11/pdp11_rc.c
@@ -437,7 +437,7 @@ static uint32 sectorCRC (const uint16 *data)
 
 static t_stat rc_svc (UNIT *uptr)
 {
-    uint32      ma, da, t, u_old, u_new, last_da;
+    uint32      ma, da, t, u_old, u_new, last_da = 0;
     uint16      dat;
     uint16      *fbuf = uptr->filebuf;
 
diff --git a/PDP11/pdp11_rf.c b/PDP11/pdp11_rf.c
index 439fa7b2..6af0f800 100644
--- a/PDP11/pdp11_rf.c
+++ b/PDP11/pdp11_rf.c
@@ -144,7 +144,7 @@ uint32 update_rfcs (uint32 newcs, uint32 newdae);
 
 DIB rf_dib = {
     IOBA_RF, IOLN_RF, &rf_rd, &rf_wr,
-    1, IVCL (RF), VEC_RF, NULL
+    1, IVCL (RF), VEC_RF, {NULL}
     };
 
 
@@ -461,7 +461,7 @@ static const uint16 boot_rom[] = {
 
 t_stat rf_boot (int32 unitno, DEVICE *dptr)
 {
-int32 i;
+size_t i;
 extern int32 saved_PC;
 
 for (i = 0; i < BOOT_LEN; i++)
diff --git a/PDP11/pdp11_rk.c b/PDP11/pdp11_rk.c
index d870ca8f..cb27b06d 100644
--- a/PDP11/pdp11_rk.c
+++ b/PDP11/pdp11_rk.c
@@ -746,7 +746,7 @@ static const uint16 boot_rom[] = {
 
 t_stat rk_boot (int32 unitno, DEVICE *dptr)
 {
-int32 i;
+size_t i;
 extern int32 saved_PC;
 
 for (i = 0; i < BOOT_LEN; i++)
diff --git a/PDP11/pdp11_rp.c b/PDP11/pdp11_rp.c
index 2b8cfef6..2faf61e6 100644
--- a/PDP11/pdp11_rp.c
+++ b/PDP11/pdp11_rp.c
@@ -1120,7 +1120,7 @@ static const uint16 boot_rom[] = {
 
 t_stat rp_boot (int32 unitno, DEVICE *dptr)
 {
-int32 i;
+size_t i;
 extern int32 saved_PC;
 extern uint16 *M;
 UNIT *uptr = rp_dev.units + unitno;
diff --git a/PDP11/pdp11_tc.c b/PDP11/pdp11_tc.c
index 1af3df29..4fc1fd19 100644
--- a/PDP11/pdp11_tc.c
+++ b/PDP11/pdp11_tc.c
@@ -749,7 +749,7 @@ t_bool dt_setpos (UNIT *uptr)
 {
 uint32 new_time, ut, ulin, udelt;
 int32 mot = DTS_GETMOT (uptr->STATE);
-int32 unum, delta;
+int32 unum, delta = 0;
 
 new_time = sim_grtime ();                               /* current time */
 ut = new_time - uptr->LASTT;                            /* elapsed time */
@@ -1183,7 +1183,7 @@ static const uint16 boot_rom[] = {
 
 t_stat dt_boot (int32 unitno, DEVICE *dptr)
 {
-int32 i;
+size_t i;
 extern int32 saved_PC;
 
 dt_unit[unitno].pos = DT_EZLIN;
diff --git a/PDP11/pdp11_tm.c b/PDP11/pdp11_tm.c
index e8430b17..55a4ef3a 100644
--- a/PDP11/pdp11_tm.c
+++ b/PDP11/pdp11_tm.c
@@ -711,7 +711,7 @@ static const uint16 boot2_rom[] = {
 
 t_stat tm_boot (int32 unitno, DEVICE *dptr)
 {
-int32 i;
+size_t i;
 extern int32 saved_PC;
 extern int32 sim_switches;
 
diff --git a/PDP11/pdp11_tu.c b/PDP11/pdp11_tu.c
index d0ced0a9..87784801 100644
--- a/PDP11/pdp11_tu.c
+++ b/PDP11/pdp11_tu.c
@@ -793,7 +793,7 @@ if (DEBUG_PRS (tu_dev)) {
     fprintf (sim_deb, ">>TU%d DONE: fnc=%s, fc=%06o, fs=%06o, er=%06o, pos=",
              drv, tu_fname[fnc], tufc, tufs, tuer);
     fprint_val (sim_deb, uptr->pos, 10, T_ADDR_W, PV_LEFT);
-    fprintf (sim_deb, "\n");
+    fprintf (sim_deb, ", r=%d\n", r);
     }
 return SCPE_OK;
 }
@@ -1036,7 +1036,7 @@ static const uint16 boot_rom[] = {
 
 t_stat tu_boot (int32 unitno, DEVICE *dptr)
 {
-int32 i;
+size_t i;
 extern int32 saved_PC;
 extern uint16 *M;