diff --git a/GRI/gri_stddev.c b/GRI/gri_stddev.c
index b05fc6cd..62c22304 100644
--- a/GRI/gri_stddev.c
+++ b/GRI/gri_stddev.c
@@ -347,7 +347,7 @@ if ((temp = getc (hsr_unit.fileref)) == EOF) {          /* read char */
             sim_printf ("HSR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("HSR I/O error");
+    else sim_perror ("HSR I/O error");
     clearerr (hsr_unit.fileref);
     return SCPE_IOERR;
     }
@@ -363,7 +363,7 @@ dev_done = dev_done | INT_HSP;                          /* set ready */
 if ((hsp_unit.flags & UNIT_ATT) == 0)                   /* attached? */
     return IORETURN (hsp_stopioe, SCPE_UNATT);
 if (putc (hsp_unit.buf, hsp_unit.fileref) == EOF) {     /* write char */
-    perror ("HSP I/O error");                           /* error? */
+    sim_perror ("HSP I/O error");                           /* error? */
     clearerr (hsp_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/H316/h316_dp.c b/H316/h316_dp.c
index ac0145c7..9f43e3b9 100644
--- a/H316/h316_dp.c
+++ b/H316/h316_dp.c
@@ -793,7 +793,7 @@ l = fxread (buf, sizeof (uint16), DP_TRKLEN, uptr->fileref);
 for ( ; l < DP_TRKLEN; l++)
     buf[l] = 0;
 if (ferror (uptr->fileref)) {
-    perror ("DP I/O error");
+    sim_perror ("DP I/O error");
     clearerr (uptr->fileref);
     dp_done (1, STA_UNSER);
     return SCPE_IOERR;
@@ -810,7 +810,7 @@ uint32 da = ((c * dp_tab[dp_ctype].surf) + h) * DP_TRKLEN;
 fseek (uptr->fileref, da * sizeof (uint16), SEEK_SET);
 fxwrite (buf, sizeof (uint16), DP_TRKLEN, uptr->fileref);
 if (ferror (uptr->fileref)) {
-    perror ("DP I/O error");
+    sim_perror ("DP I/O error");
     clearerr (uptr->fileref);
     dp_done (1, STA_UNSER);
     return SCPE_IOERR;
diff --git a/H316/h316_stddev.c b/H316/h316_stddev.c
index 0e69c782..b618d2b0 100644
--- a/H316/h316_stddev.c
+++ b/H316/h316_stddev.c
@@ -398,7 +398,7 @@ else {
                 sim_printf ("PTR end of file\n");
             else return SCPE_OK;
             }
-        else perror ("PTR I/O error");
+        else sim_perror ("PTR I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -559,7 +559,7 @@ if (uptr->flags & UNIT_ASC) {                           /* ASCII? */
     }
 else c = uptr->buf & 0377;                              /* no, binary */
 if (putc (c, uptr->fileref) == EOF) {                   /* output byte */
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
@@ -689,7 +689,7 @@ else if ((ruptr->flags & UNIT_ATT) &&                   /* TTR attached */
                     sim_printf ("TTR end of file\n");
                 else return SCPE_OK;
                 }
-            else perror ("TTR I/O error");
+            else sim_perror ("TTR I/O error");
             clearerr (ruptr->fileref);
             return SCPE_IOERR;
             }
@@ -799,7 +799,7 @@ if ((puptr->flags & UNIT_ATT) &&                        /* TTP attached */
             }
         else p = c;                                     /* untouched */
         if (putc (p, puptr->fileref) == EOF) {          /* output byte */
-            perror ("TTP I/O error");
+            sim_perror ("TTP I/O error");
             clearerr (puptr->fileref);
             return SCPE_IOERR;
             }
diff --git a/I1401/i1401_cd.c b/I1401/i1401_cd.c
index 1a56f930..a3436043 100644
--- a/I1401/i1401_cd.c
+++ b/I1401/i1401_cd.c
@@ -295,7 +295,7 @@ if ((uptr->flags & UNIT_ATT) == 0)                      /* attached? */
 fputs (cdr_buf, uptr->fileref);                         /* write card */
 uptr->pos = ftell (uptr->fileref);                      /* update position */
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("Card stacker I/O error");
+    sim_perror ("Card stacker I/O error");
     clearerr (uptr->fileref);
     if (iochk)
         return SCPE_IOERR;
@@ -375,7 +375,7 @@ fputs (cdp_buf, uptr->fileref);                         /* output card */
 fputc ('\n', uptr->fileref);                            /* plus new line */
 uptr->pos = ftell (uptr->fileref);                      /* update position */
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("Card punch I/O error");
+    sim_perror ("Card punch I/O error");
     clearerr (uptr->fileref);
     if (iochk)
         return SCPE_IOERR;
@@ -413,7 +413,7 @@ if (feof (cdr_unit.fileref))                            /* eof? */
     return STOP_NOCD;
 if (ferror (cdr_unit.fileref)) {                        /* error? */
     ind[IN_READ] = 1;  
-    perror ("Card reader I/O error");
+    sim_perror ("Card reader I/O error");
     clearerr (cdr_unit.fileref);
     if (iochk)
         return SCPE_IOERR;
diff --git a/I1401/i1401_lp.c b/I1401/i1401_lp.c
index 64dd2522..788dd9d4 100644
--- a/I1401/i1401_lp.c
+++ b/I1401/i1401_lp.c
@@ -246,7 +246,7 @@ if ((lpt_unit.flags & UNIT_ATT) != 0) {                 /* attached? */
     fputs (buf, lpt_unit.fileref);                      /* print string */
     if (ferror (lpt_unit.fileref)) {                    /* error? */
         ind[IN_LPT] = 1;
-        perror ("Line printer I/O error");
+        sim_perror ("Line printer I/O error");
         clearerr (lpt_unit.fileref);
         if (iochk)
             return SCPE_IOERR;
diff --git a/I7094/i7094_cd.c b/I7094/i7094_cd.c
index 9b286653..e0aef9e9 100644
--- a/I7094/i7094_cd.c
+++ b/I7094/i7094_cd.c
@@ -227,7 +227,7 @@ switch (cdr_sta) {                                      /* case on state */
         if (feof (uptr->fileref))                       /* eof? */
             return ch6_err_disc (CH_A, U_CDR, CHF_EOF); /* set EOF, disc */
         if (ferror (uptr->fileref)) {                   /* error? */
-            perror ("CDR I/O error");
+            sim_perror ("CDR I/O error");
             clearerr (uptr->fileref);
             return SCPE_IOERR;                          /* stop */
             }
@@ -456,7 +456,7 @@ cdp_cbuf[i++] = 0;                                      /* append nul */
 fputs (cdp_cbuf, uptr->fileref);                        /* write card */
 uptr->pos = ftell (uptr->fileref);                      /* update position */
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("CDP I/O error");
+    sim_perror ("CDP I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/I7094/i7094_dsk.c b/I7094/i7094_dsk.c
index d5b30c3d..96059730 100644
--- a/I7094/i7094_dsk.c
+++ b/I7094/i7094_dsk.c
@@ -888,7 +888,7 @@ da = DSK_DA (dsk_acc, trk, dtyp);                       /* get disk address */
 sim_fseek (udptr->fileref, da, SEEK_SET);               /* read track */
 k = sim_fread (dsk_buf, sizeof (t_uint64), dsk_tab[dtyp].wdspt, udptr->fileref);
 if (ferror (udptr->fileref)) {                          /* error? */
-    perror ("DSK I/O error");
+    sim_perror ("DSK I/O error");
     clearerr (udptr->fileref);
     dsk_uend (dsk_ch, DSKS_DSKE);
     return SCPE_IOERR;
@@ -989,7 +989,7 @@ uint32 da = DSK_DA (dsk_acc, trk, dtyp);
 sim_fseek (udptr->fileref, da, SEEK_SET);
 sim_fwrite (dsk_buf, sizeof (t_uint64), dsk_tab[dtyp].wdspt, udptr->fileref);
 if (ferror (udptr->fileref)) {
-    perror ("DSK I/O error");
+    sim_perror ("DSK I/O error");
     clearerr (udptr->fileref);
     dsk_uend (dsk_ch, DSKS_DSKE);
     return SCPE_IOERR;
diff --git a/I7094/i7094_lp.c b/I7094/i7094_lp.c
index f6aca08c..9fb56ee8 100644
--- a/I7094/i7094_lp.c
+++ b/I7094/i7094_lp.c
@@ -340,7 +340,7 @@ if (uptr->flags & UNIT_ATT) {                           /* file? */
     fputc ('\n', uptr->fileref);                        /* append nl */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* error? */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
diff --git a/Ibm1130/ibm1130_cpu.c b/Ibm1130/ibm1130_cpu.c
index 33d139e7..7e0a2e02 100644
--- a/Ibm1130/ibm1130_cpu.c
+++ b/Ibm1130/ibm1130_cpu.c
@@ -1704,7 +1704,7 @@ static t_stat cpu_attach (UNIT *uptr, char *cptr)
 			return SCPE_ARG;
 		}
 		if ((fd = fopen(mapfile, "r")) == NULL) {
-			perror(mapfile);
+			sim_perror(mapfile);
 			return SCPE_OPENERR;
 		}
 
diff --git a/Ibm1130/ibm1130_prt.c b/Ibm1130/ibm1130_prt.c
index fcee8713..f807afde 100644
--- a/Ibm1130/ibm1130_prt.c
+++ b/Ibm1130/ibm1130_prt.c
@@ -662,7 +662,7 @@ static t_stat delete_cmd (int32 flag, char *cptr)
 	status = remove(gbuf);						/* delete the file */
 
 	if (status != 0 && errno != ENOENT)			/* print message if failed and file exists */
-		perror(gbuf);
+		sim_perror(gbuf);
 
 	return SCPE_OK;
 }
diff --git a/Interdata/id_dp.c b/Interdata/id_dp.c
index 792c37e8..65887b04 100644
--- a/Interdata/id_dp.c
+++ b/Interdata/id_dp.c
@@ -463,7 +463,7 @@ i = fxread (dpxb, sizeof (uint8), DP_NUMBY, uptr->fileref);
 for ( ; i < DP_NUMBY; i++)                              /* fill with 0's */
     dpxb[i] = 0;
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("DP I/O error");
+    sim_perror ("DP I/O error");
     clearerr (uptr->fileref);
     dp_done (STC_DTE);
     return SCPE_IOERR;
@@ -479,7 +479,7 @@ for ( ; dp_bptr < DP_NUMBY; dp_bptr++)
     dpxb[dp_bptr] = dp_db;                              /* fill with last */
 fxwrite (dpxb, sizeof (uint8), DP_NUMBY, uptr->fileref);
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("DP I/O error");
+    sim_perror ("DP I/O error");
     clearerr (uptr->fileref);
     dp_done (STC_DTE);
     return SCPE_IOERR;
diff --git a/Interdata/id_idc.c b/Interdata/id_idc.c
index 42a9b02a..dae22f3e 100644
--- a/Interdata/id_idc.c
+++ b/Interdata/id_idc.c
@@ -657,7 +657,7 @@ uint32 i;
 
 i = fxread (idcxb, sizeof (uint8), IDC_NUMBY, uptr->fileref);
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("IDC I/O error");
+    sim_perror ("IDC I/O error");
     clearerr (uptr->fileref);
     idc_done (STC_DTE);
     return SCPE_IOERR;
@@ -675,7 +675,7 @@ for ( ; idc_bptr < IDC_NUMBY; idc_bptr++)
     idcxb[idc_bptr] = idc_db;                           /* fill with last */
 fxwrite (idcxb, sizeof (uint8), IDC_NUMBY, uptr->fileref);
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("IDC I/O error");
+    sim_perror ("IDC I/O error");
     clearerr (uptr->fileref);
     idc_done (STC_DTE);
     return SCPE_IOERR;
diff --git a/Interdata/id_lp.c b/Interdata/id_lp.c
index fcb1c09b..18754c08 100644
--- a/Interdata/id_lp.c
+++ b/Interdata/id_lp.c
@@ -185,7 +185,7 @@ if (lpt_spnd || ((t >= LF) && (t < CR))) {              /* spc pend or spc op? *
     else fputs ("\r", uptr->fileref);                   /* overprint */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (lpt_unit.fileref)) {
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -217,7 +217,7 @@ if (lpxb[0]) {                                          /* any char left? */
     fputs (lpxb, uptr->fileref);                        /* write line */
     lpt_unit.pos = ftell (uptr->fileref);               /* update position */
     if (ferror (uptr->fileref)) {
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         r = SCPE_IOERR;
         }
diff --git a/Interdata/id_pt.c b/Interdata/id_pt.c
index 3f4dedee..36b9d75f 100644
--- a/Interdata/id_pt.c
+++ b/Interdata/id_pt.c
@@ -207,7 +207,7 @@ if ((temp = getc (uptr->fileref)) == EOF) {             /* error? */
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("PTR I/O error");
+    else sim_perror ("PTR I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
@@ -228,7 +228,7 @@ if (!pt_rd) {                                           /* write mode? */
         SET_INT (v_PT);
     }
 if (putc (uptr->buf, uptr -> fileref) == EOF) {         /* write char */
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (uptr -> fileref);
     return SCPE_IOERR;
     }
diff --git a/LGP/lgp_stddev.c b/LGP/lgp_stddev.c
index 80657ab1..c527dd77 100644
--- a/LGP/lgp_stddev.c
+++ b/LGP/lgp_stddev.c
@@ -504,7 +504,7 @@ do {
                 sim_printf ("Reader end of file\n");
             else return SCPE_OK;
             }
-        else perror ("Reader I/O error");
+        else sim_perror ("Reader I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -519,7 +519,7 @@ do {
                     sim_printf ("Reader end of file\n");
                 else return SCPE_OK;
                 }
-            else perror ("Reader I/O error");
+            else sim_perror ("Reader I/O error");
             clearerr (uptr->fileref);
             return SCPE_IOERR;
             }
@@ -570,7 +570,7 @@ if (c >= 0)                                             /* valid? */
     sta = fputc (c, uptr->fileref);
 else sta = fprintf (uptr->fileref, "!%02d", flex);      /* no, encode */
 if (sta == EOF) {                                       /* error? */
-    perror ("Punch I/O error");                         /* error? */
+    sim_perror ("Punch I/O error");                         /* error? */
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/NOVA/nova_dkp.c b/NOVA/nova_dkp.c
index c9d50cec..224d885e 100644
--- a/NOVA/nova_dkp.c
+++ b/NOVA/nova_dkp.c
@@ -930,7 +930,7 @@ do  {
             }
 
     if (err != 0) {
-        perror ("DKP I/O error");
+        sim_perror ("DKP I/O error");
         clearerr (uptr->fileref);
         rval = SCPE_IOERR;
         break ;
diff --git a/NOVA/nova_lp.c b/NOVA/nova_lp.c
index c2e3923c..638625ac 100644
--- a/NOVA/nova_lp.c
+++ b/NOVA/nova_lp.c
@@ -134,7 +134,7 @@ if ((lpt_unit.flags & UNIT_ATT) == 0)                   /* attached? */
 fputc (uptr->buf, uptr->fileref);
 uptr->pos = ftell (uptr->fileref);
 if (ferror (uptr->fileref)) {
-    perror ("LPT I/O error");
+    sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/NOVA/nova_plt.c b/NOVA/nova_plt.c
index d24d6a97..5ded9be2 100644
--- a/NOVA/nova_plt.c
+++ b/NOVA/nova_plt.c
@@ -139,7 +139,7 @@ DEV_UPDATE_INTR ;
 if ((plt_unit.flags & UNIT_ATT) == 0)                   /* attached? */
     return IORETURN (plt_stopioe, SCPE_UNATT);
 if (putc (plt_unit.buf, plt_unit.fileref) == EOF) {
-    perror ("PLT I/O error");
+    sim_perror ("PLT I/O error");
     clearerr (plt_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/NOVA/nova_pt.c b/NOVA/nova_pt.c
index c4517edb..4aebf527 100644
--- a/NOVA/nova_pt.c
+++ b/NOVA/nova_pt.c
@@ -197,7 +197,7 @@ if ((temp = getc (ptr_unit.fileref)) == EOF) {          /* end of file? */
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("PTR I/O error");
+    else sim_perror ("PTR I/O error");
     clearerr (ptr_unit.fileref);
     return SCPE_IOERR;
     }
@@ -277,7 +277,7 @@ DEV_UPDATE_INTR ;
 if ((ptp_unit.flags & UNIT_ATT) == 0)                   /* attached? */
     return IORETURN (ptp_stopioe, SCPE_UNATT);
 if (putc ((ptp_unit.buf & ((ptp_unit.flags & UNIT_8B)? 0377: 0177)), ptp_unit.fileref) == EOF) {
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (ptp_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP1/pdp1_dt.c b/PDP1/pdp1_dt.c
index f9bd69a5..a2ecc79e 100644
--- a/PDP1/pdp1_dt.c
+++ b/PDP1/pdp1_dt.c
@@ -1112,7 +1112,7 @@ if (uptr->hwmark && ((uptr->flags & UNIT_RO) == 0)) {   /* any data? */
     else fxwrite (uptr->filebuf, sizeof (uint32),       /* write file */
         uptr->hwmark, uptr->fileref);
     if (ferror (uptr->fileref))
-        perror ("I/O error");
+        sim_perror ("I/O error");
     }                                                   /* end if hwmark */
 free (uptr->filebuf);                                   /* release buf */
 uptr->flags = uptr->flags & ~UNIT_BUF;                  /* clear buf flag */
diff --git a/PDP1/pdp1_lp.c b/PDP1/pdp1_lp.c
index ae5fe6c1..c3ec4aae 100644
--- a/PDP1/pdp1_lp.c
+++ b/PDP1/pdp1_lp.c
@@ -169,7 +169,7 @@ if (lpt_spc) {                                          /* space? */
     fputs (lpt_cc[lpt_spc & 07], uptr->fileref);        /* print cctl */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* error? */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -184,7 +184,7 @@ else {
     fputs (lpt_buf, uptr->fileref);                     /* print buffer */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* test error */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
diff --git a/PDP1/pdp1_stddev.c b/PDP1/pdp1_stddev.c
index a2f64cef..1537c196 100644
--- a/PDP1/pdp1_stddev.c
+++ b/PDP1/pdp1_stddev.c
@@ -347,7 +347,7 @@ if (temp == EOF) {                                      /* end of file? */
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("PTR I/O error");
+    else sim_perror ("PTR I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
@@ -510,7 +510,7 @@ dev_req_int (ptp_sbs);                                  /* req interrupt */
 if ((uptr->flags & UNIT_ATT) == 0)                      /* not attached? */
     return IORETURN (ptp_stopioe, SCPE_UNATT);
 if (putc (uptr->buf, uptr->fileref) == EOF) {           /* I/O error? */
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP10/pdp10_lp20.c b/PDP10/pdp10_lp20.c
index 9c2cc284..fa941d96 100644
--- a/PDP10/pdp10_lp20.c
+++ b/PDP10/pdp10_lp20.c
@@ -734,7 +734,7 @@ if (lpbc)                                               /* intr, but not done */
     update_lpcs (CSA_MBZ);
 else update_lpcs (CSA_DONE);                            /* intr and done */
 if ((fnc == FNC_PR) && ferror (lp20_unit.fileref)) {
-    perror ("LP I/O error");
+    sim_perror ("LP I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP10/pdp10_rp.c b/PDP10/pdp10_rp.c
index a8049ab9..bfe5b41e 100644
--- a/PDP10/pdp10_rp.c
+++ b/PDP10/pdp10_rp.c
@@ -1024,7 +1024,7 @@ switch (uptr->FUNC) {                                   /* case on function */
         if (err != 0) {                                 /* error? */
             set_rper (ER1_PAR, drv);                    /* set drive error */
             update_rpcs (CS1_DONE | CS1_TRE, drv);      /* set done, err */
-            perror ("RP I/O error");
+            sim_perror ("RP I/O error");
             clearerr (uptr->fileref);
             return SCPE_IOERR;
             }
diff --git a/PDP11/pdp11_hk.c b/PDP11/pdp11_hk.c
index 8c7cb971..45a8039a 100644
--- a/PDP11/pdp11_hk.c
+++ b/PDP11/pdp11_hk.c
@@ -1222,7 +1222,7 @@ switch (fnc) {                                          /* case on function */
 
         if (err != 0) {                                 /* error? */
             hk_err (CS1_ERR|CS1_DONE, 0, ER_PAR, drv);  /* set drive error */
-            perror ("HK I/O error");
+            sim_perror ("HK I/O error");
             clearerr (uptr->fileref);
             return SCPE_IOERR;
             }
diff --git a/PDP11/pdp11_lp.c b/PDP11/pdp11_lp.c
index 0a98c0cd..19c4aa58 100644
--- a/PDP11/pdp11_lp.c
+++ b/PDP11/pdp11_lp.c
@@ -167,7 +167,7 @@ if ((uptr->flags & UNIT_ATT) == 0)
 fputc (uptr->buf & 0177, uptr->fileref);
 uptr->pos = ftell (uptr->fileref);
 if (ferror (uptr->fileref)) {
-    perror ("LPT I/O error");
+    sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP11/pdp11_pt.c b/PDP11/pdp11_pt.c
index f5c27426..db190a44 100644
--- a/PDP11/pdp11_pt.c
+++ b/PDP11/pdp11_pt.c
@@ -245,7 +245,7 @@ if ((temp = getc (ptr_unit.fileref)) == EOF) {
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("PTR I/O error");
+    else sim_perror ("PTR I/O error");
     clearerr (ptr_unit.fileref);
     return SCPE_IOERR;
     }
@@ -341,7 +341,7 @@ if (ptp_csr & CSR_IE)
 if ((ptp_unit.flags & UNIT_ATT) == 0)
     return IORETURN (ptp_stopioe, SCPE_UNATT);
 if (putc (ptp_unit.buf, ptp_unit.fileref) == EOF) {
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (ptp_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP11/pdp11_rk.c b/PDP11/pdp11_rk.c
index 65a64293..ca185abd 100644
--- a/PDP11/pdp11_rk.c
+++ b/PDP11/pdp11_rk.c
@@ -767,7 +767,7 @@ rkda = (rkda & RKDA_DRIVE) | (track << RKDA_V_TRACK) | (sect << RKDA_V_SECT);
 rk_set_done (0);
 
 if (err != 0) {                                         /* error? */
-    perror ("RK I/O error");
+    sim_perror ("RK I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP11/pdp11_rl.c b/PDP11/pdp11_rl.c
index b5f7e3af..df36635b 100644
--- a/PDP11/pdp11_rl.c
+++ b/PDP11/pdp11_rl.c
@@ -953,7 +953,7 @@ if (GET_SECT (uptr->TRK) >= RL_NUMSC)
 rl_set_done (0);
 
 if (err != 0) {                                         /* error? */
-    perror ("RL I/O error");
+    sim_perror ("RL I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP11/pdp11_rp.c b/PDP11/pdp11_rp.c
index eb2ce78d..bcd9e06a 100644
--- a/PDP11/pdp11_rp.c
+++ b/PDP11/pdp11_rp.c
@@ -1252,7 +1252,7 @@ else { /* Bottom End (After I/O processing) */
                 rp_set_er (ER1_PAR, drv);               /* set drive error */
                 mba_set_exc (dibp->ba);                 /* set exception */
                 rp_update_ds (DS_ATA, drv);
-                perror ("RP I/O error");
+                sim_perror ("RP I/O error");
                 return SCPE_IOERR;
                 }
 
diff --git a/PDP11/pdp11_tc.c b/PDP11/pdp11_tc.c
index ebfdb425..5bb03a81 100644
--- a/PDP11/pdp11_tc.c
+++ b/PDP11/pdp11_tc.c
@@ -1333,7 +1333,7 @@ if (uptr->WRITTEN && uptr->hwmark && ((uptr->flags & UNIT_RO)== 0)) {    /* any
             fxwrite (uptr->filebuf, sizeof (uint32),    /* write file */
                      uptr->hwmark, uptr->fileref);
     if (ferror (uptr->fileref))
-        perror ("I/O error");
+        sim_perror ("I/O error");
     }
 uptr->WRITTEN = FALSE;                                  /* no longer dirty */
 }
diff --git a/PDP11/pdp11_tq.c b/PDP11/pdp11_tq.c
index 0c083929..5724ef0e 100644
--- a/PDP11/pdp11_tq.c
+++ b/PDP11/pdp11_tq.c
@@ -1497,7 +1497,7 @@ t_stat tq_mot_err (UNIT *uptr, uint32 rsiz)
 uptr->flags = (uptr->flags | UNIT_SXC) & ~UNIT_TMK;     /* serious exception */
 if (tq_dte (uptr, ST_DRV))                              /* post err log */
     tq_mot_end (uptr, EF_LOG, ST_DRV, rsiz);            /* if ok, report err */
-perror ("TQ I/O error");
+sim_perror ("TQ I/O error");
 clearerr (uptr->fileref);
 return SCPE_IOERR;
 }
diff --git a/PDP18B/pdp18b_dt.c b/PDP18B/pdp18b_dt.c
index 151b044d..8cfcc276 100644
--- a/PDP18B/pdp18b_dt.c
+++ b/PDP18B/pdp18b_dt.c
@@ -1528,7 +1528,7 @@ if (uptr->WRITTEN && uptr->hwmark && ((uptr->flags & UNIT_RO)== 0)) {    /* any
             fxwrite (uptr->filebuf, sizeof (uint32),       /* write file */
                      uptr->hwmark, uptr->fileref);
     if (ferror (uptr->fileref))
-        perror ("I/O error");
+        sim_perror ("I/O error");
     }
 uptr->WRITTEN = FALSE;                                  /* no longer dirty */
 }
diff --git a/PDP18B/pdp18b_lp.c b/PDP18B/pdp18b_lp.c
index 801f05f1..7588ff09 100644
--- a/PDP18B/pdp18b_lp.c
+++ b/PDP18B/pdp18b_lp.c
@@ -185,7 +185,7 @@ if (lp62_spc) {                                         /* space? */
     fputs (lp62_cc[lp62_spc & 07], uptr->fileref);      /* print cctl */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* error? */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -200,7 +200,7 @@ else {
     fputs (lp62_buf, uptr->fileref);                    /* print buffer */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* test error */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -427,7 +427,7 @@ if ((lp647_iot & 020) == 0) {                           /* print? */
     fputs (pbuf, uptr->fileref);                        /* print buffer */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* error? */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         lp647_bp = 0;
         return SCPE_IOERR;
@@ -438,7 +438,7 @@ if (lp647_iot & 060) {                                  /* space? */
     fputs (lp647_cc[lp647_iot & 07], uptr->fileref);    /* write cctl */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* error? */
-        perror ("LPT I/O error");
+        sim_perror ("LPT I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
@@ -610,7 +610,7 @@ if ((c == 0) || (c == 0177))                            /* skip NULL, DEL */
 fputc (c, uptr->fileref);                               /* print char */
 uptr->pos = ftell (uptr->fileref);                      /* update position */
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("LPT I/O error");
+    sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
@@ -824,7 +824,7 @@ for (more = 1; more != 0; ) {                           /* loop until ctrl */
             fputs (ctrl[c[i]], uptr->fileref);          /* space */
             uptr->pos = ftell (uptr->fileref);
             if (ferror (uptr->fileref)) {               /* error? */
-                perror ("LPT I/O error");
+                sim_perror ("LPT I/O error");
                 clearerr (uptr->fileref);
                 lp15_bp = 0;
                 lp15_updsta (STA_DON | STA_ALM);
diff --git a/PDP18B/pdp18b_rp.c b/PDP18B/pdp18b_rp.c
index e1a0755d..398061da 100644
--- a/PDP18B/pdp18b_rp.c
+++ b/PDP18B/pdp18b_rp.c
@@ -432,7 +432,7 @@ rp_busy = 0;                                            /* clear busy */
 rp_updsta (STA_DON, 0);                                 /* set done */
 
 if (err != 0) {                                         /* error? */
-    perror ("RP I/O error");
+    sim_perror ("RP I/O error");
     clearerr (uptr->fileref);
     return IORETURN (rp_stopioe, SCPE_IOERR);
     }
diff --git a/PDP18B/pdp18b_stddev.c b/PDP18B/pdp18b_stddev.c
index 4b202d31..5d217714 100644
--- a/PDP18B/pdp18b_stddev.c
+++ b/PDP18B/pdp18b_stddev.c
@@ -576,7 +576,7 @@ if ((temp = getc (ptr_unit.fileref)) == EOF) {          /* end of file? */
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("PTR I/O error");
+    else sim_perror ("PTR I/O error");
     clearerr (ptr_unit.fileref);
     return SCPE_IOERR;
     }
@@ -918,7 +918,7 @@ if (ptp_unit.flags & UNIT_PASCII) {                     /* ASCII mode? */
     }
 if (putc (ptp_unit.buf, ptp_unit.fileref) == EOF) {     /* I/O error? */
     ptp_err = 1;                                        /* set error */
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (ptp_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP8/pdp8_dt.c b/PDP8/pdp8_dt.c
index 69fa5e97..e9f85aa3 100644
--- a/PDP8/pdp8_dt.c
+++ b/PDP8/pdp8_dt.c
@@ -1312,7 +1312,7 @@ if (uptr->WRITTEN && uptr->hwmark && ((uptr->flags & UNIT_RO)== 0)) {    /* any
             }                                           /* end loop buf */
         }                                               /* end else */
     if (ferror (uptr->fileref))
-        perror ("I/O error");
+        sim_perror ("I/O error");
     }
 uptr->WRITTEN = FALSE;                                  /* no longer dirty */
 }
diff --git a/PDP8/pdp8_lp.c b/PDP8/pdp8_lp.c
index 6c111367..98db6c12 100644
--- a/PDP8/pdp8_lp.c
+++ b/PDP8/pdp8_lp.c
@@ -143,7 +143,7 @@ if ((uptr->flags & UNIT_ATT) == 0) {
 fputc (uptr->buf, uptr->fileref);                       /* print char */
 uptr->pos = ftell (uptr->fileref);
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("LPT I/O error");
+    sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP8/pdp8_pt.c b/PDP8/pdp8_pt.c
index 01c8bbae..f8dca656 100644
--- a/PDP8/pdp8_pt.c
+++ b/PDP8/pdp8_pt.c
@@ -167,7 +167,7 @@ if ((temp = getc (ptr_unit.fileref)) == EOF) {
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else sim_printf ("PTR I/O error: %d\n", errno);
+    else sim_perror ("PTR I/O error");
     clearerr (ptr_unit.fileref);
     return SCPE_IOERR;
     }
@@ -231,7 +231,7 @@ int_req = INT_UPDATE;                                   /* update interrupts */
 if ((ptp_unit.flags & UNIT_ATT) == 0)                   /* attached? */
     return IORETURN (ptp_stopioe, SCPE_UNATT);
 if (putc (ptp_unit.buf, ptp_unit.fileref) == EOF) {
-    perror ("PTP I/O error");
+    sim_perror ("PTP I/O error");
     clearerr (ptp_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP8/pdp8_rk.c b/PDP8/pdp8_rk.c
index ef057a0b..3d692b00 100644
--- a/PDP8/pdp8_rk.c
+++ b/PDP8/pdp8_rk.c
@@ -408,7 +408,7 @@ rk_busy = 0;
 RK_INT_UPDATE;
 
 if (err != 0) {
-    perror ("RK I/O error");
+    sim_perror ("RK I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP8/pdp8_rl.c b/PDP8/pdp8_rl.c
index d078a9de..e1a47f1a 100644
--- a/PDP8/pdp8_rl.c
+++ b/PDP8/pdp8_rl.c
@@ -521,7 +521,7 @@ rlsa = rlsa + ((bc + (RL_NUMBY - 1)) / RL_NUMBY);
 rl_set_done (0);
 
 if (err != 0) {                                         /* error? */
-    perror ("RL I/O error");
+    sim_perror ("RL I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/PDP8/pdp8_td.c b/PDP8/pdp8_td.c
index 5fd06746..1b3b5497 100644
--- a/PDP8/pdp8_td.c
+++ b/PDP8/pdp8_td.c
@@ -893,7 +893,7 @@ if (uptr->WRITTEN && uptr->hwmark && ((uptr->flags & UNIT_RO)== 0)) {    /* any
             }                                           /* end loop buf */
         }                                               /* end else */
     if (ferror (uptr->fileref))
-        perror ("I/O error");
+        sim_perror ("I/O error");
     }
 uptr->WRITTEN = FALSE;                                  /* no longer dirty */
 }
diff --git a/S3/s3_cd.c b/S3/s3_cd.c
index 7c5b2423..0a335164 100644
--- a/S3/s3_cd.c
+++ b/S3/s3_cd.c
@@ -311,7 +311,7 @@ if (feof (cdr_unit.fileref)) {                          /* eof? */
     return STOP_NOCD;
 }       
 if (ferror (cdr_unit.fileref)) {                        /* error? */
-    perror ("Card reader I/O error");
+    sim_perror ("Card reader I/O error");
     clearerr (cdr_unit.fileref);
     carderr = 1;  
     return SCPE_OK;  }
@@ -352,7 +352,7 @@ rbuf[CDR_WIDTH] = 0;                                    /* null at end */
 fputs (rbuf, uptr -> fileref);                          /* write card */
 fputc ('\n', uptr -> fileref);                          /* plus new line */
 if (ferror (uptr -> fileref)) {                         /* error? */
-    perror ("Card stacker I/O error");
+    sim_perror ("Card stacker I/O error");
     clearerr (uptr -> fileref);
 }
 uptr -> pos = ftell (uptr -> fileref);                  /* update position */
@@ -397,7 +397,7 @@ if (!cdp_ebcdic) {
     }   
 }   
 if (ferror (uptr -> fileref)) {                         /* error? */
-    perror ("Card punch I/O error");
+    sim_perror ("Card punch I/O error");
     clearerr (uptr -> fileref);
     pcherror = 1;
 }
diff --git a/S3/s3_lp.c b/S3/s3_lp.c
index a0507f50..ff1fa307 100644
--- a/S3/s3_lp.c
+++ b/S3/s3_lp.c
@@ -240,7 +240,7 @@ else {
 }
 lines = lflag = 0;                                      /* clear cc action */
 if (ferror (lpt_unit.fileref)) {                        /* error? */
-    perror ("Line printer I/O error");
+    sim_perror ("Line printer I/O error");
     clearerr (lpt_unit.fileref);
     lpterror = 1;
 }
diff --git a/SAGE/sage_lp.c b/SAGE/sage_lp.c
index 201ac177..698ef078 100644
--- a/SAGE/sage_lp.c
+++ b/SAGE/sage_lp.c
@@ -234,7 +234,7 @@ static t_stat sagelp_output(UNIT *uptr)
     if ((u39.portc & U39C_STROBE)==0) { /* strobe presented */
         fputc (uptr->buf & 0177, uptr->fileref);    /* put out char */
         if (ferror (uptr->fileref)) {
-            perror ("LP I/O error");
+            sim_perror ("LP I/O error");
             clearerr (uptr->fileref);
             return SCPE_IOERR;
         }
diff --git a/SDS/sds_lp.c b/SDS/sds_lp.c
index 1462bd88..1c961875 100644
--- a/SDS/sds_lp.c
+++ b/SDS/sds_lp.c
@@ -245,7 +245,7 @@ if (uptr->flags & UNIT_ATT) {                           /* attached? */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* I/O error? */
         lpt_end_op (CHF_EOR | CHF_ERR);                 /* set err, disc */
-        perror ("LPT I/O error");                       /* print msg */
+        sim_perror ("LPT I/O error");                       /* print msg */
         clearerr (uptr->fileref);
         return SCPE_IOERR;                              /* ret error */
         }
diff --git a/SDS/sds_stddev.c b/SDS/sds_stddev.c
index 864a8ba7..f9685de2 100644
--- a/SDS/sds_stddev.c
+++ b/SDS/sds_stddev.c
@@ -280,7 +280,7 @@ if ((temp = getc (ptr_unit.fileref)) == EOF) {          /* end of file? */
             sim_printf ("PTR end of file\n");
         else return SCPE_OK;
         }
-    else perror ("PTR I/O error");                      /* I/O error */
+    else sim_perror ("PTR I/O error");                      /* I/O error */
     clearerr (ptr_unit.fileref);
     return SCPE_IOERR;
     }
@@ -414,7 +414,7 @@ if ((ptp_unit.flags & UNIT_ATT) == 0) {                 /* attached? */
     }
 if (putc (dat, ptp_unit.fileref) == EOF) {              /* I/O error? */
     ptp_set_err ();                                     /* yes, disc, err */
-    perror ("PTP I/O error");                           /* print msg */
+    sim_perror ("PTP I/O error");                           /* print msg */
     clearerr (ptp_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/TX-0/tx0_stddev.c b/TX-0/tx0_stddev.c
index b23cf7d9..ac0f09ac 100644
--- a/TX-0/tx0_stddev.c
+++ b/TX-0/tx0_stddev.c
@@ -366,7 +366,7 @@ if ((uptr->flags & UNIT_ATT) == 0) {                    /* attached? */
                 ios = 0;
                 return SCPE_IOERR;
         }
-        else perror ("PETR I/O error");
+        else sim_perror ("PETR I/O error");
         clearerr (uptr->fileref);
         ios = 0;
         return SCPE_IOERR;
@@ -533,7 +533,7 @@ t_stat ptp_svc (UNIT *uptr)
     if ((uptr->flags & UNIT_ATT) == 0)                      /* not attached? */
         return SCPE_UNATT;
     if (putc (uptr->buf, uptr->fileref) == EOF) {           /* I/O error? */
-        perror ("PTP I/O error");
+        sim_perror ("PTP I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
         }
diff --git a/VAX/vax730_rb.c b/VAX/vax730_rb.c
index 0c5cdfc7..56866c81 100644
--- a/VAX/vax730_rb.c
+++ b/VAX/vax730_rb.c
@@ -592,7 +592,7 @@ rbda = rbda + ((wc + (RB_NUMWD(uptr) - 1)) / RB_NUMWD(uptr));
 rb_set_done (0);
 
 if (err != 0) {                                         /* error? */
-    perror ("RB I/O error");
+    sim_perror ("RB I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
diff --git a/VAX/vax_sysdev.c b/VAX/vax_sysdev.c
index a179ca83..5518a7ef 100644
--- a/VAX/vax_sysdev.c
+++ b/VAX/vax_sysdev.c
@@ -816,7 +816,7 @@ if (cso_csr & CSR_IE)
 if ((cso_unit.flags & UNIT_ATT) == 0)
     return SCPE_OK;
 if (putc (cso_unit.buf, cso_unit.fileref) == EOF) {
-    perror ("CSO I/O error");
+    sim_perror ("CSO I/O error");
     clearerr (cso_unit.fileref);
     return SCPE_IOERR;
     }
diff --git a/scp.c b/scp.c
index 15032b42..fb5f1074 100644
--- a/scp.c
+++ b/scp.c
@@ -5272,7 +5272,7 @@ if (uptr->flags & UNIT_BUF) {
         rewind (uptr->fileref);
         sim_fwrite (uptr->filebuf, SZ_D (dptr), cap, uptr->fileref);
         if (ferror (uptr->fileref))
-            perror ("I/O error");
+            sim_printf ("%s: I/O error - %s", sim_dname (dptr), strerror (errno));
         }
     if (uptr->flags & UNIT_MUSTBUF) {                   /* dyn alloc? */
         free (uptr->filebuf);                           /* free buf */
@@ -9581,6 +9581,11 @@ if (buf != stackbuf)
     free (buf);
 }
 
+void sim_perror (const char *msg)
+{
+sim_printf ("%s: %s\n", msg, strerror (errno));
+}
+
 /* Print command result message to stdout, sim_log (if enabled) and sim_deb (if enabled) */
 t_stat sim_messagef (t_stat stat, const char* fmt, ...)
 {
diff --git a/scp.h b/scp.h
index cb1d96a4..cd8d0150 100644
--- a/scp.h
+++ b/scp.h
@@ -186,6 +186,7 @@ const char *sim_error_text (t_stat stat);
 t_stat sim_string_to_stat (char *cptr, t_stat *cond);
 t_stat sim_cancel_step (void);
 void sim_printf (const char* fmt, ...);
+void sim_perror (const char* msg);
 t_stat sim_messagef (t_stat stat, const char* fmt, ...);
 void sim_data_trace(DEVICE *dptr, UNIT *uptr, const uint8 *data, const char *position, size_t len, const char *txt, uint32 reason);
 void sim_debug_bits (uint32 dbits, DEVICE* dptr, BITFIELD* bitdefs,
diff --git a/sigma/sigma_dp.c b/sigma/sigma_dp.c
index 322a1b42..0990ed72 100644
--- a/sigma/sigma_dp.c
+++ b/sigma/sigma_dp.c
@@ -1081,7 +1081,7 @@ t_stat dp_ioerr (UNIT *uptr)
 uint32 cidx = uptr->UCTX;
 uint32 dva = dp_dib[cidx].dva;
 
-perror ("DP I/O error");
+sim_perror ("DP I/O error");
 clearerr (uptr->fileref);
 dp_ctx[cidx].dp_flags |= DPF_DPE;                       /* set DPE flag */
 chan_set_chf (dva, CHF_XMDE);
diff --git a/sigma/sigma_lp.c b/sigma/sigma_lp.c
index 48794286..e125be04 100644
--- a/sigma/sigma_lp.c
+++ b/sigma/sigma_lp.c
@@ -353,7 +353,7 @@ if (skp && CHP (CH_TOF, lp_cct[lp_cctp]))               /* skip, TOF? */
         }
 uptr->pos = ftell (uptr->fileref);                      /* update position */
 if (ferror (uptr->fileref)) {                           /* error? */
-    perror ("Line printer I/O error");
+    sim_perror ("Line printer I/O error");
     clearerr (uptr->fileref);
     chan_set_chf (lp_dib.dva, CHF_XMDE);
     return SCPE_IOERR;
@@ -388,7 +388,7 @@ if ((lp_model == LP_7440) || lp_pass) {                 /* ready to print? */
     fputc (lp_inh? '\r': '\n', uptr->fileref);          /* cr or nl */
     uptr->pos = ftell (uptr->fileref);                  /* update position */
     if (ferror (uptr->fileref)) {                       /* error? */
-        perror ("Line printer I/O error");
+        sim_perror ("Line printer I/O error");
         clearerr (uptr->fileref);
         chan_set_chf (lp_dib.dva, CHF_XMDE);
         return SCPE_IOERR;
diff --git a/sigma/sigma_pt.c b/sigma/sigma_pt.c
index f5507f6b..1ffe60ed 100644
--- a/sigma/sigma_pt.c
+++ b/sigma/sigma_pt.c
@@ -186,7 +186,7 @@ switch (pt_cmd) {                                       /* case on state */
                 break;
                 }
             else {                                      /* real error */
-                perror ("PTR I/O error");
+                sim_perror ("PTR I/O error");
                 clearerr (uptr->fileref);
                 chan_set_chf (pt_dib.dva, CHF_XMDE);    /* data error */
                 return pt_chan_err (SCPE_IOERR);        /* force uend */
@@ -212,7 +212,7 @@ switch (pt_cmd) {                                       /* case on state */
         if (CHS_IFERR (st))                             /* channel error? */
             return pt_chan_err (st);
         if (putc (c, pt_unit[PTP].fileref) == EOF) {
-            perror ("PTP I/O error");
+            sim_perror ("PTP I/O error");
             clearerr (pt_unit[PTP].fileref);
             chan_set_chf (pt_dib.dva, CHF_XMDE);        /* data error */
             return pt_chan_err (SCPE_IOERR);            /* force uend */
diff --git a/sim_disk.c b/sim_disk.c
index 1f0438a0..584984ea 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -1355,7 +1355,7 @@ switch (DK_GET_FMT (uptr)) {                            /* case on format */
     case DKUF_F_STD:                                    /* SIMH format */
     case DKUF_F_VHD:                                    /* VHD format */
     case DKUF_F_RAW:                                    /* Raw Physical Disk Access */
-        perror (msg);
+        sim_printf ("%s %s: %s\n", sim_uname(uptr), msg, strerror(errno));
     default:
         ;
     }
diff --git a/sim_tape.c b/sim_tape.c
index 96c536f3..c7367f7c 100644
--- a/sim_tape.c
+++ b/sim_tape.c
@@ -2050,7 +2050,7 @@ return ((uptr->flags & MTUF_WRP) || (MT_GET_FMT (uptr) == MTUF_F_TPC))? TRUE: FA
 
 t_stat sim_tape_ioerr (UNIT *uptr)
 {
-perror ("Magtape library I/O error");
+sim_printf ("%s: Magtape library I/O error: %s\n", sim_uname (uptr), strerror (errno));
 clearerr (uptr->fileref);
 return MTSE_IOERR;
 }