diff --git a/Interdata/id_fd.c b/Interdata/id_fd.c
index d4944394..3293eb14 100644
--- a/Interdata/id_fd.c
+++ b/Interdata/id_fd.c
@@ -1,6 +1,6 @@
 /* id_fd.c: Interdata floppy disk simulator
 
-   Copyright (c) 2001-2013, Robert M Supnik
+   Copyright (c) 2001-2021, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -25,6 +25,7 @@
 
    fd           M46-630 floppy disk
 
+   31-Jan-21    RMS     Revised for new register macros
    03-Sep-13    RMS     Added explicit void * cast
    19-Mar-12    RMS     Fixed macro naming conflict (Mark Pizzolato)
 
@@ -169,7 +170,7 @@ REG fd_reg[] = {
     { HRDATA (STA, fd_sta, 8) },
     { HRDATA (BUF, fd_db, 8) },
     { HRDATA (LRN, fd_lrn, 16) },
-    { BRDATA (ESTA, fd_es, 16, 8, ES_SIZE * FD_NUMDR) },
+    { CRDATA (ESTA, fd_es, 16, 8, ES_SIZE * FD_NUMDR) },
     { BRDATA (DBUF, fdxb, 16, 8, FD_NUMBY) },
     { HRDATA (DBPTR, fd_bptr, 8) },
     { FLDATA (WDV, fd_wdv, 0) },
diff --git a/PDP11/pdp11_rq.c b/PDP11/pdp11_rq.c
index ffbdb085..25af52ac 100644
--- a/PDP11/pdp11_rq.c
+++ b/PDP11/pdp11_rq.c
@@ -1,6 +1,6 @@
 /* pdp11_rq.c: MSCP disk controller simulator
 
-   Copyright (c) 2002-2018, Robert M Supnik
+   Copyright (c) 2002-2022, Robert M Supnik
    Derived from work by Stephen F. Shirron
 
    Permission is hereby granted, free of charge, to any person obtaining a
@@ -26,6 +26,8 @@
 
    rq           RQDX3 disk controller
 
+   06=Mar-22    RMS     Added more disk types (Mark Pizzolato)
+   31-Jan-21    RMS     Revised for new register macros
    28-May-18    RMS     Changed to avoid nested comment warnings (Mark Pizzolato)
    23-Oct-13    RMS     Revised for new boot setup routine
    17-Mar-13    RMS     Fixed bug in ABORT link walk loop (Dave Bryan)
@@ -249,6 +251,7 @@ x  RA73 70(+1)  21      2667+   21      1       ?       3920490
 #define RQDF_RMV        01                              /* removable */
 #define RQDF_RO         02                              /* read only */
 #define RQDF_SDI        04                              /* SDI drive */
+#define RQDF_DSSI       010                             /* DSSI drive */
 
 #define RX50_DTYPE      0
 #define RX50_SECT       10
@@ -525,6 +528,160 @@ x  RA73 70(+1)  21      2667+   21      1       ?       3920490
 #define RD32_MED        0x25644020
 #define RD32_FLGS       0
 
+/* Below here, imported from V4 */
+
+#define RC25_DTYPE      17                              /*  */
+#define RC25_SECT       50                              /*  */
+#define RC25_SURF       8
+#define RC25_CYL        1260                            /*  */
+#define RC25_TPG        RC25_SURF
+#define RC25_GPC        1
+#define RC25_XBN        0                               /*  */
+#define RC25_DBN        0                               /*  */
+#define RC25_LBN        50902                           /* ? 50*8*1260 ? */
+#define RC25_RCTS       0                               /*  */
+#define RC25_RCTC       1
+#define RC25_RBN        0                               /*  */
+#define RC25_MOD        2
+#define RC25_MED        0x20643019
+#define RC25_FLGS       RQDF_RMV
+
+#define RCF25_DTYPE     18                              /*  */
+#define RCF25_SECT      50                              /*  */
+#define RCF25_SURF      8
+#define RCF25_CYL       1260                            /*  */
+#define RCF25_TPG       RCF25_SURF
+#define RCF25_GPC       1
+#define RCF25_XBN       0                               /*  */
+#define RCF25_DBN       0                               /*  */
+#define RCF25_LBN       50902                           /* ? 50*8*1260 ? */
+#define RCF25_RCTS      0                               /*  */
+#define RCF25_RCTC      1
+#define RCF25_RBN       0                               /*  */
+#define RCF25_MOD       3
+#define RCF25_MED       0x20643319
+#define RCF25_FLGS      0
+
+#define RA80_DTYPE      19                              /* SDI drive */
+#define RA80_SECT       31                              /* +1 spare/track */
+#define RA80_SURF       14
+#define RA80_CYL        546                             /*  */
+#define RA80_TPG        RA80_SURF
+#define RA80_GPC        1
+#define RA80_XBN        0                               /*  */
+#define RA80_DBN        0                               /*  */
+#define RA80_LBN        237212                          /* 31*14*546 */
+#define RA80_RCTS       0                               /*  */
+#define RA80_RCTC       1
+#define RA80_RBN        0                               /*  */
+#define RA80_MOD        1
+#define RA80_MED        0x25641050
+#define RA80_FLGS       RQDF_SDI
+
+// [RLA] Most of these RA70 parameters came from doing a DUSTAT on a real
+// [RLA] RA70 drive.  The remainder are just educated guesses...
+
+#define RA70_DTYPE      20                             /* SDI drive */
+#define RA70_SECT       33                             /* +1 spare/track */
+#define RA70_SURF       11                             /* tracks/cylinder */
+#define RA70_CYL        1507                           /* 0-1506 user */
+#define RA70_TPG        RA70_SURF
+#define RA70_GPC        1
+#define RA70_XBN        0                              /* ??? */
+#define RA70_DBN        0                              /* ??? */
+#define RA70_LBN        547041                         /* 33*11*1507 */
+#define RA70_RCTS       198                            /* Size of the RCT */
+#define RA70_RCTC       7                              /* Number of RCT copies */
+#define RA70_RBN        16577                          /* 1*11*1507 */
+#define RA70_MOD        18
+#define RA70_MED        0x25641046                     /* RA70 MEDIA ID */
+#define RA70_FLGS       RQDF_SDI
+
+// [RLA] Likewise for the RA73 ...
+#define RA73_DTYPE      21                             /* SDI drive */
+#define RA73_SECT       70                             /* +1 spare/track */
+#define RA73_SURF       21                             /* tracks/cylinder */
+#define RA73_CYL        2667                           /* 0-2666 user */
+#define RA73_TPG        RA73_SURF
+#define RA73_GPC        1
+#define RA73_XBN        0                              /* ??? */
+#define RA73_DBN        0                              /* ??? */
+#define RA73_LBN        3920490                        /* 70*21*2667 */
+#define RA73_RCTS       198                            /* Size of the RCT ??????*/
+#define RA73_RCTC       7                              /* Number of RCT copies */
+#define RA73_RBN        56007                          /* 1*21*2667 */
+#define RA73_MOD        47
+#define RA73_MED        0x25641049                     /* RA73 MEDIA ID */
+#define RA73_FLGS       RQDF_SDI
+
+/* The RF drives don't have any useful error parameters. */
+/* These entries are derived from basic geometry and size */
+/* info in Ultrix 4.5 disktab entries. */
+
+#define RF30_DTYPE      22                              /* DSSI drive */
+#define RF30_SECT       37                              /* +1 spare/track */
+#define RF30_SURF       6
+#define RF30_CYL        1320                            /* 0-1914 user */
+#define RF30_TPG        RF30_SURF
+#define RF30_GPC        1
+#define RF30_XBN        1456                            /* cyl 1917-1918? */
+#define RF30_DBN        1456                            /* cyl 1919-1920? */
+#define RF30_LBN        293040                          /* 37*6*1320 */
+#define RF30_RCTS       1428                            /* cyl 1915-1916? */
+#define RF30_RCTC       1
+#define RF30_RBN        26810                           /* 1 *14*1915 */
+#define RF30_MOD        21
+#define RF30_MED        0x2264601E
+#define RF30_FLGS       RQDF_DSSI
+
+#define RF31_DTYPE      23                              /* DSSI drive */
+#define RF31_SECT       50                              /* +1 spare/track */
+#define RF31_SURF       8
+#define RF31_CYL        1861                            /* 0-1860 user */
+#define RF31_TPG        RF31_SURF
+#define RF31_GPC        1
+#define RF31_XBN        1456                            /* cyl 1917-1918? */
+#define RF31_DBN        1456                            /* cyl 1919-1920? */
+#define RF31_LBN        744400                          /* 50*8*1861 */
+#define RF31_RCTS       1428                            /* cyl 1915-1916? */
+#define RF31_RCTC       1
+#define RF31_RBN        26810                           /* 1 *14*1915 */
+#define RF31_MOD        27
+#define RF31_MED        0x2264601F
+#define RF31_FLGS       RQDF_DSSI
+
+#define RF71_DTYPE      24                              /* DSSI drive */
+#define RF71_SECT       37                              /* +1 spare/track */
+#define RF71_SURF       16
+#define RF71_CYL        1320                            /* 0-1914 user */
+#define RF71_TPG        RF71_SURF
+#define RF71_GPC        1
+#define RF71_XBN        1456                            /* cyl 1917-1918? */
+#define RF71_DBN        1456                            /* cyl 1919-1920? */
+#define RF71_LBN        781440                          /* 37*16*1320 */
+#define RF71_RCTS       1428                            /* cyl 1915-1916? */
+#define RF71_RCTC       1
+#define RF71_RBN        26810                           /* 1 *14*1915 */
+#define RF71_MOD        40
+#define RF71_MED        0x22646047
+#define RF71_FLGS       RQDF_DSSI
+
+#define RF72_DTYPE      25                              /* DSSI drive */
+#define RF72_SECT       50                              /* +1 spare/track */
+#define RF72_SURF       21
+#define RF72_CYL        1861                            /* 0-1860 user */
+#define RF72_TPG        RF72_SURF
+#define RF72_GPC        1
+#define RF72_XBN        1456                            /* cyl 1917-1918? */
+#define RF72_DBN        1456                            /* cyl 1919-1920? */
+#define RF72_LBN        1954050                         /* 50*21*1861 */
+#define RF72_RCTS       1428                            /* cyl 1915-1916? */
+#define RF72_RCTC       1
+#define RF72_RBN        26810                           /* 1 *14*1915 */
+#define RF72_MOD        28
+#define RF72_MED        0x22646048
+#define RF72_FLGS       RQDF_DSSI
+
 struct drvtyp {
     int32       sect;                                   /* sectors */
     int32       surf;                                   /* surfaces */
@@ -551,15 +708,87 @@ struct drvtyp {
 #define RQ_SIZE(d)      (d##_LBN * RQ_NUMBY)
 
 static struct drvtyp drv_tab[] = {
-    { RQ_DRV (RX50), "RX50" }, { RQ_DRV (RX33), "RX33" },
-    { RQ_DRV (RD51), "RD51" }, { RQ_DRV (RD31), "RD31" },
-    { RQ_DRV (RD52), "RD52" }, { RQ_DRV (RD53), "RD53" },
-    { RQ_DRV (RD54), "RD54" }, { RQ_DRV (RA82), "RA82" },
-    { RQ_DRV (RRD40), "RRD40" }, { RQ_DRV (RA72), "RA72" },
-    { RQ_DRV (RA90), "RA90" }, { RQ_DRV (RA92), "RA92" },
-    { RQ_DRV (RA8U), "RAUSER" }, { RQ_DRV (RA60), "RA60" },
-    { RQ_DRV (RA81), "RA81" }, { RQ_DRV (RA71), "RA71" },
+    { RQ_DRV (RX50), "RX50" },
+    { RQ_DRV (RX33), "RX33" },
+    { RQ_DRV (RD51), "RD51" },
+    { RQ_DRV (RD31), "RD31" },
+    { RQ_DRV (RD52), "RD52" },
+    { RQ_DRV (RD53), "RD53" },
+    { RQ_DRV (RD54), "RD54" },
+    { RQ_DRV (RA82), "RA82" },
+    { RQ_DRV (RRD40), "RRD40" },
+    { RQ_DRV (RA72), "RA72" },
+    { RQ_DRV (RA90), "RA90" },
+    { RQ_DRV (RA92), "RA82" },
+    { RQ_DRV (RA8U), "RAUSER" },
+    { RQ_DRV (RA60), "RA60" },
+    { RQ_DRV (RA81), "RA81" },
+    { RQ_DRV (RA71), "RA71" },
     { RQ_DRV (RD32), "RD32" },
+    { RQ_DRV (RC25), "RC25" },
+    { RQ_DRV (RCF25), "RCF25" },
+    { RQ_DRV (RA80), "RA80" },
+    { RQ_DRV (RA70), "RA70" },
+    { RQ_DRV (RA73), "RA73" },
+    { RQ_DRV (RF30), "RF30" },
+    { RQ_DRV (RF31), "RF31" },
+    { RQ_DRV (RF71), "RF71" },
+    { RQ_DRV (RF72), "RF72" },
+    { 0 }
+    };
+
+/* Controller parameters */
+
+#define DEFAULT_CTYPE   0
+
+// AFAIK the UNIBUS KLESI and QBUS KLESI used the same controller type...
+
+#define KLESI_CTYPE     1               // RC25 controller (UNIBUS and QBUS both)
+#define KLESI_UQPM      1
+#define KLESI_MODEL     1
+
+#define RUX50_CTYPE     2               // UNIBUS RX50-only controller
+#define RUX50_UQPM      2
+#define RUX50_MODEL     2
+
+#define UDA50_CTYPE     3               // UNIBUS SDI (RAxx) controller
+#define UDA50_UQPM      6
+#define UDA50_MODEL     6
+
+#define RQDX3_CTYPE     4               // QBUS RX50/RDxx controller
+#define RQDX3_UQPM      19
+#define RQDX3_MODEL     19
+
+#define KDA50_CTYPE     5               // QBUS SDI (RAxx) controller
+#define KDA50_UQPM      13
+#define KDA50_MODEL     13
+
+#define KRQ50_CTYPE     6               // QBUS RRD40/50 CDROM controller
+#define KRQ50_UQPM      16
+#define KRQ50_MODEL     16
+
+#define KRU50_CTYPE     7               // UNIBUS RRD40/50 CDROM controller
+#define KRU50_UQPM      26
+#define KRU50_MODEL     26
+
+struct ctlrtyp {
+    uint32      uqpm;                                   /* port model */
+    uint16      model;                                  /* controller model */
+    const char  *name;                                  /* name */
+    };
+
+#define RQ_CTLR(d) \
+    d##_UQPM, d##_MODEL
+
+static struct ctlrtyp ctlr_tab[] = {
+    { 0, 0, "DEFAULT" },
+    { RQ_CTLR (KLESI), "KLESI" },
+    { RQ_CTLR (RUX50), "RUX50" },
+    { RQ_CTLR (UDA50), "UDA50" },
+    { RQ_CTLR (RQDX3), "RQDX3" },
+    { RQ_CTLR (KDA50), "KDA50" },
+    { RQ_CTLR (KRQ50), "KRQ50" },
+    { RQ_CTLR (KRU50), "KRU50" },
     { 0 }
     };
 
@@ -592,6 +821,7 @@ typedef struct {
     uint32              credits;                        /* credits */
     uint32              hat;                            /* host timer */
     uint32              htmo;                           /* host timeout */
+//    uint32              ctype;                          /* controller type */
     struct uq_ring      cq;                             /* cmd ring */
     struct uq_ring      rq;                             /* rsp ring */
     struct rqpkt        pak[RQ_NPKTS];                  /* packet queue */
@@ -708,7 +938,7 @@ REG rq_reg[] = {
     { DRDATA (I4TIME, rq_itime4, 24), PV_LEFT + REG_NZ },
     { DRDATA (QTIME, rq_qtime, 24), PV_LEFT + REG_NZ },
     { DRDATA (XTIME, rq_xtime, 24), PV_LEFT + REG_NZ },
-    { BRDATA (PKTS, rq_ctx.pak, DEV_RDX, 16, RQ_NPKTS * (RQ_PKT_SIZE_W + 1)) },
+    { XRDATA (PKTS, rq_ctx.pak, DEV_RDX, 16, 0, RQ_NPKTS * (RQ_PKT_SIZE_W + 1), sizeof (int16), sizeof (int16)) },
     { URDATA (CPKT, rq_unit[0].cpkt, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (PKTQ, rq_unit[0].pktq, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (UFLG, rq_unit[0].uf, DEV_RDX, 16, 0, RQ_NUMDR, 0) },
@@ -754,6 +984,8 @@ MTAB rq_mod[] = {
       &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA60_DTYPE, NULL, "RA60",
       &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RA80_DTYPE, NULL, "RA80",
+      &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA81_DTYPE, NULL, "RA81",
       &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA82_DTYPE, NULL, "RA82",
@@ -762,16 +994,32 @@ MTAB rq_mod[] = {
       &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RRD40_DTYPE, NULL, "CDROM",
       &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RA70_DTYPE, NULL, "RA70",
+      &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA71_DTYPE, NULL, "RA71",
       &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA72_DTYPE, NULL, "RA72",
       &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RA73_DTYPE, NULL, "RA73",
+      &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA90_DTYPE, NULL, "RA90",
       &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA92_DTYPE, NULL, "RA92",
       &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, RA8U_DTYPE, NULL, "RAUSER",
       &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RC25_DTYPE, NULL, "RC25",
+      &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RCF25_DTYPE, NULL, "RCF25",
+      &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RF30_DTYPE, NULL, "RF30",
+      &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RF31_DTYPE, NULL, "RF31",
+      &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RA8U_DTYPE, NULL, "RAUSER",
+      &rq_set_type, NULL, NULL },
+    { MTAB_XTD | MTAB_VUN, RA8U_DTYPE, NULL, "RA8U",
+      &rq_set_type, NULL, NULL },
     { MTAB_XTD | MTAB_VUN, 0, "TYPE", NULL,
       NULL, &rq_show_type, NULL },
 #if defined (VM_PDP11)
@@ -847,7 +1095,7 @@ REG rqb_reg[] = {
     { FLDATA (PRGI, rqb_ctx.prgi, 0), REG_HIDDEN },
     { FLDATA (PIP, rqb_ctx.pip, 0), REG_HIDDEN },
     { FLDATA (INT, rqb_ctx.irq, 0) },
-    { BRDATA (PKTS, rqb_ctx.pak, DEV_RDX, 16, RQ_NPKTS * (RQ_PKT_SIZE_W + 1)) },
+    { XRDATA (PKTS, rqb_ctx.pak, DEV_RDX, 16, 0, RQ_NPKTS * (RQ_PKT_SIZE_W + 1), sizeof (int16), sizeof (int16)) },
     { URDATA (CPKT, rqb_unit[0].cpkt, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (PKTQ, rqb_unit[0].pktq, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (UFLG, rqb_unit[0].uf, DEV_RDX, 16, 0, RQ_NUMDR, 0) },
@@ -916,7 +1164,7 @@ REG rqc_reg[] = {
     { FLDATA (PRGI, rqc_ctx.prgi, 0), REG_HIDDEN },
     { FLDATA (PIP, rqc_ctx.pip, 0), REG_HIDDEN },
     { FLDATA (INT, rqc_ctx.irq, 0) },
-    { BRDATA (PKTS, rqc_ctx.pak, DEV_RDX, 16, RQ_NPKTS * (RQ_PKT_SIZE_W + 1)) },
+    { XRDATA (PKTS, rqc_ctx.pak, DEV_RDX, 16, 0, RQ_NPKTS * (RQ_PKT_SIZE_W + 1), sizeof (int16), sizeof (int16)) },
     { URDATA (CPKT, rqc_unit[0].cpkt, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (PKTQ, rqc_unit[0].pktq, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (UFLG, rqc_unit[0].uf, DEV_RDX, 16, 0, RQ_NUMDR, 0) },
@@ -985,7 +1233,7 @@ REG rqd_reg[] = {
     { FLDATA (PRGI, rqd_ctx.prgi, 0), REG_HIDDEN },
     { FLDATA (PIP, rqd_ctx.pip, 0), REG_HIDDEN },
     { FLDATA (INT, rqd_ctx.irq, 0) },
-    { BRDATA (PKTS, rqd_ctx.pak, DEV_RDX, 16, RQ_NPKTS * (RQ_PKT_SIZE_W + 1)) },
+    { XRDATA (PKTS, rqd_ctx.pak, DEV_RDX, 16, 0, RQ_NPKTS * (RQ_PKT_SIZE_W + 1), sizeof (int16), sizeof (int16)) },
     { URDATA (CPKT, rqd_unit[0].cpkt, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (PKTQ, rqd_unit[0].pktq, 10, 5, 0, RQ_NUMDR, 0) },
     { URDATA (UFLG, rqd_unit[0].uf, DEV_RDX, 16, 0, RQ_NUMDR, 0) },
diff --git a/doc/pdp11_doc.doc b/doc/pdp11_doc.doc
index e37deaeb..e2fdbe0c 100644
Binary files a/doc/pdp11_doc.doc and b/doc/pdp11_doc.doc differ
diff --git a/doc/simh_doc.doc b/doc/simh_doc.doc
index 9ca95cf7..a62660c3 100644
Binary files a/doc/simh_doc.doc and b/doc/simh_doc.doc differ
diff --git a/makefile b/makefile
index c40c57b0..68b8271c 100644
--- a/makefile
+++ b/makefile
@@ -1,13 +1,17 @@
 #
 # This GNU make makefile has been tested on:
-#   Linux (x86 & Sparc)
+#   Linux (x86 & Sparc & PPC)
+#   Android (Termux)
 #   OS X
-#   Solaris (x86 & Sparc)
+#   Solaris (x86 & Sparc) (gcc and Sun C)
 #   OpenBSD
 #   NetBSD
 #   FreeBSD
+#   HP-UX
+#   AIX
 #   Windows (MinGW & cygwin)
 #   Linux x86 targeting Android (using agcc script)
+#   Haiku x86 (with gcc4)
 #
 # Android targeted builds should invoke GNU make with GCC=agcc on
 # the command line.
@@ -15,40 +19,182 @@
 # In general, the logic below will detect and build with the available
 # features which the host build environment provides.
 #
-# Dynamic loading of libpcap is the default behavior if pcap.h is
-# available at build time.  Direct calls to libpcap can be enabled
-# if GNU make is invoked with USE_NETWORK=1 on the command line.
+# Dynamic loading of libpcap is the preferred default behavior if pcap.h 
+# is available at build time.  Support to statically linking against libpcap
+# is deprecated and may be removed in the future.  Static linking against 
+# libpcap can be enabled if GNU make is invoked with USE_NETWORK=1 on the 
+# command line.
+#
+# Some platforms may not have vendor supplied libpcap available.  HP-UX is 
+# one such example.  The packages which are available for this platform
+# install include files and libraries in user specified directories.  In 
+# order for this makefile to locate where these components may have been 
+# installed, gmake should be invoked with LPATH=/usr/lib:/usr/local/lib 
+# defined (adjusted as needed depending on where they may be installed).
+#
+# In the unlikely event that someone wants to build network capable 
+# simulators without networking support, invoking GNU make with 
+# NONETWORK=1 on the command line will do the trick.
+#
+# By default, video support is enabled if the SDL2 development
+# headers and libraries are available.  To force a build without video
+# support, invoke GNU make with NOVIDEO=1 on the command line.
 #
 # The default build will build compiler optimized binaries.
 # If debugging is desired, then GNU make can be invoked with
 # DEBUG=1 on the command line.
 #
+# The default build will run per simulator tests if they are 
+# available.  If building without running tests is desired, 
+# then GNU make should be invoked with TESTS=0 on the command 
+# line.
+#
+# Default test execution will produce summary output.  Detailed
+# test output can be produced if GNU make is invoked with 
+# TEST_ARG=-v on the command line.
+#
+# simh project support is provided for simulators that are built with 
+# dependent packages provided with the or by the operating system 
+# distribution OR for platforms where that isn't directly available 
+# (OS X/macOS) by packages from specific package management systems (MacPorts 
+# or Homebrew).  Users wanting to build simulators with locally built 
+# dependent packages or packages provided by an unsupported package 
+# management system may be able to override where this procedure looks 
+# for include files and/or libraries.  Overrides can be specified by define 
+# exported environment variables or GNU make command line arguments which 
+# specify INCLUDES and/or LIBRARIES.  
+# Each of these, if specified, must be the complete list include directories
+# or library directories that should be used with each element separated by 
+# colons. (i.e. INCLUDES=/usr/include/:/usr/local/include/:...)
+# If this doesn't work for you and/or you're interested in using a different 
+# ToolChain, you're free to solve this problem on your own.  Good Luck.
+#
+# Some environments may have the LLVM (clang) compiler installed as
+# an alternate to gcc.  If you want to build with the clang compiler, 
+# invoke make with GCC=clang.
+#
+# Internal ROM support can be disabled if GNU make is invoked with
+# DONT_USE_ROMS=1 on the command line.
+#
 # For linting (or other code analyzers) make may be invoked similar to:
 #
 #   make GCC=cppcheck CC_OUTSPEC= LDFLAGS= CFLAGS_G="--enable=all --template=gcc" CC_STD=--std=c99
 #
 # CC Command (and platform available options).  (Poor man's autoconf)
 #
-# building the pdp11, or any vax simulator could use networking support
-# No Asynch I/O support for now.
-NOASYNCH = 1
-BUILD_SINGLE := $(MAKECMDGOALS) $(BLANK_PREFIX)
-ifneq (,$(or $(findstring pdp11,$(MAKECMDGOALS)),$(findstring vax,$(MAKECMDGOALS)),$(findstring all,$(MAKECMDGOALS))))
+ifneq (,${GREP_OPTIONS})
+  $(info GREP_OPTIONS is defined in your environment.)
+  $(info )
+  $(info This variable interfers with the proper operation of this script.)
+  $(info )
+  $(info The GREP_OPTIONS environment variable feature of grep is deprecated)
+  $(info for exactly this reason and will be removed from future versions of)
+  $(info grep.  The grep man page suggests that you use an alias or a script)
+  $(info to invoke grep with your preferred options.)
+  $(info )
+  $(info unset the GREP_OPTIONS environment variable to use this makefile)
+  $(error 1)
+endif
+ifeq (old,$(shell gmake --version /dev/null 2>&1 | grep 'GNU Make' | awk '{ if ($$3 < "3.81") {print "old"} }'))
+  GMAKE_VERSION = $(shell gmake --version /dev/null 2>&1 | grep 'GNU Make' | awk '{ print $$3 }')
+  $(warning *** Warning *** GNU Make Version $(GMAKE_VERSION) is too old to)
+  $(warning *** Warning *** fully process this makefile)
+endif
+BUILD_SINGLE := ${MAKECMDGOALS} $(BLANK_SUFFIX)
+BUILD_MULTIPLE_VERB = is
+# building the pdp1, pdp11, tx-0, or any microvax simulator could use video support
+ifneq (,$(or $(findstring XXpdp1XX,$(addsuffix XX,$(addprefix XX,${MAKECMDGOALS}))),$(findstring pdp11,${MAKECMDGOALS}),$(findstring tx-0,${MAKECMDGOALS}),$(findstring microvax1,${MAKECMDGOALS}),$(findstring microvax2,${MAKECMDGOALS}),$(findstring microvax3900,${MAKECMDGOALS}),$(findstring microvax2000,${MAKECMDGOALS}),$(findstring vaxstation3100,${MAKECMDGOALS}),$(findstring XXvaxXX,$(addsuffix XX,$(addprefix XX,${MAKECMDGOALS})))))
+  VIDEO_USEFUL = true
+endif
+# building the besm6 needs both video support and fontfile support
+ifneq (,$(findstring besm6,${MAKECMDGOALS}))
+  VIDEO_USEFUL = true
+  BESM6_BUILD = true
+endif
+# building the Imlac needs video support
+ifneq (,$(findstring imlac,${MAKECMDGOALS}))
+  VIDEO_USEFUL = true
+endif
+# building the TT2500 needs video support
+ifneq (,$(findstring tt2500,${MAKECMDGOALS}))
+  VIDEO_USEFUL = true
+endif
+# building the PDP6, KA10 or KI10 needs video support
+ifneq (,$(or $(findstring pdp6,${MAKECMDGOALS}),$(findstring pdp10-ka,${MAKECMDGOALS}),$(findstring pdp10-ki,${MAKECMDGOALS})))
+  VIDEO_USEFUL = true
+endif
+# building the KA10, KI10 or KL10 networking can be used.
+ifneq (,$(or $(findstring pdp10-ka,${MAKECMDGOALS}),$(findstring pdp10-ki,${MAKECMDGOALS},$(findstring pdp10-kl,${MAKECMDGOALS}))))
   NETWORK_USEFUL = true
-  ifneq (,$(findstring all,$(MAKECMDGOALS))$(word 2,$(MAKECMDGOALS)))
+endif
+# building the PDP-7 needs video support
+ifneq (,$(findstring pdp7,${MAKECMDGOALS}))
+  VIDEO_USEFUL = true
+endif
+# building the pdp11, pdp10, or any vax simulator could use networking support
+ifneq (,$(or $(findstring pdp11,${MAKECMDGOALS}),$(findstring pdp10,${MAKECMDGOALS}),$(findstring vax,${MAKECMDGOALS}),$(findstring infoserver,${MAKECMDGOALS}),$(findstring 3b2,${MAKECMDGOALS})$(findstring all,${MAKECMDGOALS})))
+  NETWORK_USEFUL = true
+  ifneq (,$(findstring all,${MAKECMDGOALS}))
     BUILD_MULTIPLE = s
+    BUILD_MULTIPLE_VERB = are
+    VIDEO_USEFUL = true
+    BESM6_BUILD = true
+  endif
+  ifneq (,$(word 2,${MAKECMDGOALS}))
+    BUILD_MULTIPLE = s
+    BUILD_MULTIPLE_VERB = are
   endif
 else
-  ifeq ($(MAKECMDGOALS),)
+  ifeq (${MAKECMDGOALS},)
     # default target is all
     NETWORK_USEFUL = true
+    VIDEO_USEFUL = true
     BUILD_MULTIPLE = s
-    BUILD_SINGLE := all $(BLANK_PREFIX)
+    BUILD_MULTIPLE_VERB = are
+    BUILD_SINGLE := all $(BUILD_SINGLE)
+    BESM6_BUILD = true
   endif
 endif
-ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
-  ifeq ($(GCC),)
-    GCC = gcc
+# someone may want to explicitly build simulators without network support
+ifneq ($(NONETWORK),)
+  NETWORK_USEFUL =
+endif
+# ... or without video support
+ifneq ($(NOVIDEO),)
+  VIDEO_USEFUL =
+endif
+ifneq ($(findstring Windows,${OS}),)
+  ifeq ($(findstring .exe,${SHELL}),.exe)
+    # MinGW
+    WIN32 := 1
+    # Tests don't run under MinGW
+    TESTS := 0
+  else # Msys or cygwin
+    ifeq (MINGW,$(findstring MINGW,$(shell uname)))
+      $(info *** This makefile can not be used with the Msys bash shell)
+      $(error Use build_mingw.bat ${MAKECMDGOALS} from a Windows command prompt)
+    endif
+  endif
+endif
+
+find_exe = $(abspath $(strip $(firstword $(foreach dir,$(strip $(subst :, ,${PATH})),$(wildcard $(dir)/$(1))))))
+find_lib = $(abspath $(strip $(firstword $(foreach dir,$(strip ${LIBPATH}),$(wildcard $(dir)/lib$(1).${LIBEXT})))))
+find_include = $(abspath $(strip $(firstword $(foreach dir,$(strip ${INCPATH}),$(wildcard $(dir)/$(1).h)))))
+ifneq (0,$(TESTS))
+  find_test = RegisterSanityCheck $(abspath $(wildcard $(1)/tests/$(2)_test.ini)) </dev/null
+  TESTING_FEATURES = - Per simulator tests will be run
+else
+  TESTING_FEATURES = - Per simulator tests will be skipped
+endif
+ifeq (${WIN32},)  #*nix Environments (&& cygwin)
+  ifeq (${GCC},)
+    ifeq (,$(shell which gcc 2>/dev/null))
+      $(info *** Warning *** Using local cc since gcc isn't available locally.)
+      $(info *** Warning *** You may need to install gcc to build working simulators.)
+      GCC = cc
+    else
+      GCC = gcc
+    endif
   endif
   OSTYPE = $(shell uname)
   # OSNAME is used in messages to indicate the source of libpcap components
@@ -62,69 +208,112 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
     OSTYPE = cygwin
     OSNAME = windows-build
   endif
-  ifeq (,$(shell $(GCC) -v /dev/null 2>&1 | grep 'clang'))
-    GCC_VERSION = $(shell $(GCC) -v /dev/null 2>&1 | grep 'gcc version' | awk '{ print $$3 }')
+  ifeq (Darwin,$(OSTYPE))
+    ifeq (,$(shell which port)$(shell which brew))
+      $(info *** Info *** simh dependent packages on macOS must be provided by either the)
+      $(info *** Info *** MacPorts package system or by the HomeBrew package system.)
+      $(info *** Info *** Neither of these seem to be installed on the local system.)
+      $(info *** Info ***)
+      ifeq (,$(INCLUDES)$(LIBRARIES))
+        $(info *** Info *** Users wanting to build simulators with locally built dependent)
+        $(info *** Info *** packages or packages provided by an unsupported package)
+        $(info *** Info *** management system may be able to override where this procedure)
+        $(info *** Info *** looks for include files and/or libraries.  Overrides can be)
+        $(info *** Info *** specified by defining exported environment variables or GNU make)
+        $(info *** Info *** command line arguments which specify INCLUDES and/or LIBRARIES.)
+        $(info *** Info *** If this works, that's great, if it doesn't you are on your own!)
+      else
+        $(info *** Warning *** Attempting to build on macOS with:)
+        $(info *** Warning *** INCLUDES defined as $(INCLUDES))
+        $(info *** Warning *** and)
+        $(info *** Warning *** LIBRARIES defined as $(LIBRARIES))
+      endif
+    endif
+  endif
+  ifeq (,$(shell ${GCC} -v /dev/null 2>&1 | grep 'clang'))
+    GCC_VERSION = $(shell ${GCC} -v /dev/null 2>&1 | grep 'gcc version' | awk '{ print $$3 }')
     COMPILER_NAME = GCC Version: $(GCC_VERSION)
     ifeq (,$(GCC_VERSION))
       ifeq (SunOS,$(OSTYPE))
-        ifneq (,$(shell $(GCC) -V 2>&1 | grep 'Sun C'))
-          SUNC_VERSION = $(shell $(GCC) -V 2>&1 | grep 'Sun C')
+        ifneq (,$(shell ${GCC} -V 2>&1 | grep 'Sun C'))
+          SUNC_VERSION = $(shell ${GCC} -V 2>&1 | grep 'Sun C')
           COMPILER_NAME = $(wordlist 2,10,$(SUNC_VERSION))
           CC_STD = -std=c99
         endif
       endif
       ifeq (HP-UX,$(OSTYPE))
-        ifneq (,$(shell what `which $(firstword $(GCC)) 2>&1`| grep -i compiler))
-          COMPILER_NAME = $(strip $(shell what `which $(firstword $(GCC)) 2>&1` | grep -i compiler))
+        ifneq (,$(shell what `which $(firstword ${GCC}) 2>&1`| grep -i compiler))
+          COMPILER_NAME = $(strip $(shell what `which $(firstword ${GCC}) 2>&1` | grep -i compiler))
           CC_STD = -std=gnu99
         endif
       endif
     else
-      ifeq (,$(findstring ++,$(GCC)))
+      ifeq (,$(findstring ++,${GCC}))
         CC_STD = -std=gnu99
       else
         CPP_BUILD = 1
       endif
     endif
   else
-    NO_LTO = 1
-    OS_CCDEFS += -Wno-parentheses
-    ifeq (Apple,$(shell $(GCC) -v /dev/null 2>&1 | grep 'Apple' | awk '{ print $$1 }'))
-      COMPILER_NAME = $(shell $(GCC) -v /dev/null 2>&1 | grep 'Apple' | awk '{ print $$1 " " $$2 " " $$3 " " $$4 }')
+    ifeq (Apple,$(shell ${GCC} -v /dev/null 2>&1 | grep 'Apple' | awk '{ print $$1 }'))
+      COMPILER_NAME = $(shell ${GCC} -v /dev/null 2>&1 | grep 'Apple' | awk '{ print $$1 " " $$2 " " $$3 " " $$4 }')
       CLANG_VERSION = $(word 4,$(COMPILER_NAME))
     else
-      COMPILER_NAME = $(shell $(GCC) -v /dev/null 2>&1 | grep 'clang version' | awk '{ print $$1 " " $$2 " " $$3 }')
+      COMPILER_NAME = $(shell ${GCC} -v /dev/null 2>&1 | grep 'clang version' | awk '{ print $$1 " " $$2 " " $$3 }')
       CLANG_VERSION = $(word 3,$(COMPILER_NAME))
       ifeq (,$(findstring .,$(CLANG_VERSION)))
-        COMPILER_NAME = $(shell $(GCC) -v /dev/null 2>&1 | grep 'clang version' | awk '{ print $$1 " " $$2 " " $$3 " " $$4 }')
+        COMPILER_NAME = $(shell ${GCC} -v /dev/null 2>&1 | grep 'clang version' | awk '{ print $$1 " " $$2 " " $$3 " " $$4 }')
         CLANG_VERSION = $(word 4,$(COMPILER_NAME))
       endif
     endif
-    ifeq (,$(findstring ++,$(GCC)))
+    ifeq (,$(findstring ++,${GCC}))
       CC_STD = -std=c99
     else
       CPP_BUILD = 1
+      OS_CCDEFS += -Wno-deprecated
+    endif
+  endif
+  ifeq (git-repo,$(shell if ${TEST} -e ./.git; then echo git-repo; fi))
+    GIT_PATH=$(strip $(shell which git))
+    ifeq (,$(GIT_PATH))
+      $(error building using a git repository, but git is not available)
+    endif
+    ifeq (commit-id-exists,$(shell if ${TEST} -e .git-commit-id; then echo commit-id-exists; fi))
+      CURRENT_GIT_COMMIT_ID=$(strip $(shell grep 'SIM_GIT_COMMIT_ID' .git-commit-id | awk '{ print $$2 }'))
+      ACTUAL_GIT_COMMIT_ID=$(strip $(shell git log -1 --pretty="%H"))
+      ifneq ($(CURRENT_GIT_COMMIT_ID),$(ACTUAL_GIT_COMMIT_ID))
+        NEED_COMMIT_ID = need-commit-id
+        # make sure that the invalidly formatted .git-commit-id file wasn't generated
+        # by legacy git hooks which need to be removed.
+        $(shell rm -f .git/hooks/post-checkout .git/hooks/post-commit .git/hooks/post-merge)
+      endif
+    else
+      NEED_COMMIT_ID = need-commit-id
+    endif
+    ifneq (,$(shell git update-index --refresh --))
+      GIT_EXTRA_FILES=+uncommitted-changes
+    endif
+    ifneq (,$(or $(NEED_COMMIT_ID),$(GIT_EXTRA_FILES)))
+      isodate=$(shell git log -1 --pretty="%ai"|sed -e 's/ /T/'|sed -e 's/ //')
+      $(shell git log -1 --pretty="SIM_GIT_COMMIT_ID %H$(GIT_EXTRA_FILES)%nSIM_GIT_COMMIT_TIME $(isodate)" >.git-commit-id)
     endif
   endif
   LTO_EXCLUDE_VERSIONS = 
   PCAPLIB = pcap
-  ifeq (agcc,$(findstring agcc,$(GCC))) # Android target build?
-    OS_CCDEFS = -D_GNU_SOURCE
-    ifeq (,$(NOASYNCH))
-      OS_CCDEFS += -DSIM_ASYNCH_IO 
-    endif
+  ifeq (agcc,$(findstring agcc,${GCC})) # Android target build?
+    OS_CCDEFS = -D_GNU_SOURCE -DSIM_ASYNCH_IO 
     OS_LDFLAGS = -lm
   else # Non-Android (or Native Android) Builds
     ifeq (,$(INCLUDES)$(LIBRARIES))
-      INCPATH:=$(shell LANG=C; $(GCC) -x c -v -E /dev/null 2>&1 | grep -A 10 '> search starts here' | grep '^ ' | tr -d '\n')
-      ifeq (,$(INCPATH))
+      INCPATH:=$(shell LANG=C; ${GCC} -x c -v -E /dev/null 2>&1 | grep -A 10 '> search starts here' | grep '^ ' | tr -d '\n')
+      ifeq (,${INCPATH})
         INCPATH:=/usr/include
       endif
       LIBPATH:=/usr/lib
     else
       $(info *** Warning ***)
       ifeq (,$(INCLUDES))
-        INCPATH:=$(shell LANG=C; $(GCC) -x c -v -E /dev/null 2>&1 | grep -A 10 '> search starts here' | grep '^ ' | tr -d '\n')
+        INCPATH:=$(shell LANG=C; ${GCC} -x c -v -E /dev/null 2>&1 | grep -A 10 '> search starts here' | grep '^ ' | tr -d '\n')
       else
         $(info *** Warning *** Unsupported build with INCLUDES defined as: $(INCLUDES))
         INCPATH:=$(strip $(subst :, ,$(INCLUDES)))
@@ -144,30 +333,31 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
       $(info *** Warning ***)
     endif
     OS_CCDEFS += -D_GNU_SOURCE
-    GCC_OPTIMIZERS_CMD = $(GCC) -v --help 2>&1
-    GCC_WARNINGS_CMD = $(GCC) -v --help 2>&1
-    LD_ELF = $(shell echo | $(GCC) -E -dM - | grep __ELF__)
+    GCC_OPTIMIZERS_CMD = ${GCC} -v --help 2>&1
+    GCC_WARNINGS_CMD = ${GCC} -v --help 2>&1
+    LD_ELF = $(shell echo | ${GCC} -E -dM - | grep __ELF__)
     ifeq (Darwin,$(OSTYPE))
       OSNAME = OSX
       LIBEXT = dylib
       ifneq (include,$(findstring include,$(UNSUPPORTED_BUILD)))
-        INCPATH:=$(shell LANG=C; $(GCC) -x c -v -E /dev/null 2>&1 | grep -A 10 '> search starts here' | grep '^ ' | grep -v 'framework directory' | tr -d '\n')
+        INCPATH:=$(shell LANG=C; ${GCC} -x c -v -E /dev/null 2>&1 | grep -A 10 '> search starts here' | grep '^ ' | grep -v 'framework directory' | tr -d '\n')
       endif
-      ifeq (incopt,$(shell if $(TEST) -d /opt/local/include; then echo incopt; fi))
+      ifeq (incopt,$(shell if ${TEST} -d /opt/local/include; then echo incopt; fi))
         INCPATH += /opt/local/include
         OS_CCDEFS += -I/opt/local/include
       endif
-      ifeq (libopt,$(shell if $(TEST) -d /opt/local/lib; then echo libopt; fi))
+      ifeq (libopt,$(shell if ${TEST} -d /opt/local/lib; then echo libopt; fi))
         LIBPATH += /opt/local/lib
         OS_LDFLAGS += -L/opt/local/lib
       endif
-      ifeq (HomeBrew,$(shell if $(TEST) -d /usr/local/Cellar; then echo HomeBrew; fi))
-        INCPATH += $(foreach dir,$(wildcard /usr/local/Cellar/*/*),$(dir)/include)
-        LIBPATH += $(foreach dir,$(wildcard /usr/local/Cellar/*/*),$(dir)/lib)
-      endif
-      ifeq (libXt,$(shell if $(TEST) -d /usr/X11/lib; then echo libXt; fi))
-        LIBPATH += /usr/X11/lib
-        OS_LDFLAGS += -L/usr/X11/lib
+      ifeq (HomeBrew,$(or $(shell if ${TEST} -d /usr/local/Cellar; then echo HomeBrew; fi),$(shell if ${TEST} -d /opt/homebrew/Cellar; then echo HomeBrew; fi)))
+        ifeq (local,$(shell if $(TEST) -d /usr/local/Cellar; then echo local; fi))
+          HBPATH = /usr/local
+        else
+          HBPATH = /opt/homebrew
+        endif
+        INCPATH += $(foreach dir,$(wildcard $(HBPATH)/Cellar/*/*),$(realpath $(dir)/include))
+        LIBPATH += $(foreach dir,$(wildcard $(HBPATH)/Cellar/*/*),$(realpath $(dir)/lib))
       endif
     else
       ifeq (Linux,$(OSTYPE))
@@ -176,12 +366,15 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
         endif
         ifneq (lib,$(findstring lib,$(UNSUPPORTED_BUILD)))
           ifeq (Android,$(shell uname -o))
-            ifneq (,$(shell if $(TEST) -d /system/lib; then echo systemlib; fi))
+            ifneq (,$(shell if ${TEST} -d ${PREFIX}/lib; then echo prefixlib; fi))
+              LIBPATH += ${PREFIX}/lib
+            endif
+            ifneq (,$(shell if ${TEST} -d /system/lib; then echo systemlib; fi))
               LIBPATH += /system/lib
             endif
             LIBPATH += $(LD_LIBRARY_PATH)
           endif
-          ifeq (ldconfig,$(shell if $(TEST) -e /sbin/ldconfig; then echo ldconfig; fi))
+          ifeq (ldconfig,$(shell if ${TEST} -e /sbin/ldconfig; then echo ldconfig; fi))
             LIBPATH := $(sort $(foreach lib,$(shell /sbin/ldconfig -p | grep ' => /' | sed 's/^.* => //'),$(dir $(lib))))
           endif
         endif
@@ -194,11 +387,11 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
           endif
           LIBEXT = so
           OS_LDFLAGS += -lsocket -lnsl
-          ifeq (incsfw,$(shell if $(TEST) -d /opt/sfw/include; then echo incsfw; fi))
+          ifeq (incsfw,$(shell if ${TEST} -d /opt/sfw/include; then echo incsfw; fi))
             INCPATH += /opt/sfw/include
             OS_CCDEFS += -I/opt/sfw/include
           endif
-          ifeq (libsfw,$(shell if $(TEST) -d /opt/sfw/lib; then echo libsfw; fi))
+          ifeq (libsfw,$(shell if ${TEST} -d /opt/sfw/lib; then echo libsfw; fi))
             LIBPATH += /opt/sfw/lib
             OS_LDFLAGS += -L/opt/sfw/lib -R/opt/sfw/lib
           endif
@@ -206,18 +399,18 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
         else
           ifeq (cygwin,$(OSTYPE))
             # use 0readme_ethernet.txt documented Windows pcap build components
-            INCPATH += ../windows-build/winpcap/WpdPack/include
-            LIBPATH += ../windows-build/winpcap/WpdPack/lib
+            INCPATH += ../windows-build/winpcap/WpdPack/Include
+            LIBPATH += ../windows-build/winpcap/WpdPack/Lib
             PCAPLIB = wpcap
             LIBEXT = a
           else
             ifneq (,$(findstring AIX,$(OSTYPE)))
               OS_LDFLAGS += -lm -lrt
-              ifeq (incopt,$(shell if $(TEST) -d /opt/freeware/include; then echo incopt; fi))
+              ifeq (incopt,$(shell if ${TEST} -d /opt/freeware/include; then echo incopt; fi))
                 INCPATH += /opt/freeware/include
                 OS_CCDEFS += -I/opt/freeware/include
               endif
-              ifeq (libopt,$(shell if $(TEST) -d /opt/freeware/lib; then echo libopt; fi))
+              ifeq (libopt,$(shell if ${TEST} -d /opt/freeware/lib; then echo libopt; fi))
                 LIBPATH += /opt/freeware/lib
                 OS_LDFLAGS += -L/opt/freeware/lib
               endif
@@ -255,23 +448,17 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
                       LIBPATH = $(subst :, ,$(LPATH))
                     endif
                   endif
-                  OS_LDFLAGS += $(patsubst %,-L%,$(LIBPATH))
+                  OS_LDFLAGS += $(patsubst %,-L%,${LIBPATH})
                 endif
               endif
             endif
-            ifeq (usrpkglib,$(shell if $(TEST) -d /usr/pkg/lib; then echo usrpkglib; fi))
+            ifeq (usrpkglib,$(shell if ${TEST} -d /usr/pkg/lib; then echo usrpkglib; fi))
               LIBPATH += /usr/pkg/lib
               INCPATH += /usr/pkg/include
               OS_LDFLAGS += -L/usr/pkg/lib -R/usr/pkg/lib
               OS_CCDEFS += -I/usr/pkg/include
             endif
-            ifeq (X11R7,$(shell if $(TEST) -d /usr/X11R7/lib; then echo X11R7; fi))
-              LIBPATH += /usr/X11R7/lib
-              INCPATH += /usr/X11R7/include
-              OS_LDFLAGS += -L/usr/X11R7/lib -R/usr/X11R7/lib
-              OS_CCDEFS += -I/usr/X11R7/include
-            endif
-            ifeq (/usr/local/lib,$(findstring /usr/local/lib,$(LIBPATH)))
+            ifeq (/usr/local/lib,$(findstring /usr/local/lib,${LIBPATH}))
               INCPATH += /usr/local/include
               OS_CCDEFS += -I/usr/local/include
             endif
@@ -295,19 +482,31 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
         endif
       endif
     endif
+    ifeq (,$(filter /lib/,$(LIBPATH)))
+      ifeq (existlib,$(shell if $(TEST) -d /lib/; then echo existlib; fi))
+        LIBPATH += /lib/
+      endif
+    endif
+    ifeq (,$(filter /usr/lib/,$(LIBPATH)))
+      ifeq (existusrlib,$(shell if $(TEST) -d /usr/lib/; then echo existusrlib; fi))
+        LIBPATH += /usr/lib/
+      endif
+    endif
+    export CPATH = $(subst $() $(),:,$(INCPATH))
+    export LIBRARY_PATH = $(subst $() $(),:,$(LIBPATH))
     # Some gcc versions don't support LTO, so only use LTO when the compiler is known to support it
     ifeq (,$(NO_LTO))
       ifneq (,$(GCC_VERSION))
-        ifeq (,$(shell $(GCC) -v /dev/null 2>&1 | grep '\-\-enable-lto'))
+        ifeq (,$(shell ${GCC} -v /dev/null 2>&1 | grep '\-\-enable-lto'))
           LTO_EXCLUDE_VERSIONS += $(GCC_VERSION)
         endif
       endif
     endif
   endif
-  $(info lib paths are: $(LIBPATH))
-  $(info include paths are: $(INCPATH))
-  find_lib = $(strip $(firstword $(foreach dir,$(strip $(LIBPATH)),$(wildcard $(dir)/lib$(1).$(LIBEXT)))))
-  find_include = $(strip $(firstword $(foreach dir,$(strip $(INCPATH)),$(wildcard $(dir)/$(1).h))))
+  $(info lib paths are: ${LIBPATH})
+  $(info include paths are: ${INCPATH})
+  need_search = $(strip $(shell ld -l$(1) /dev/null 2>&1 | grep $(1) | sed s/$(1)//))
+  LD_SEARCH_NEEDED := $(call need_search,ZzzzzzzZ)
   ifneq (,$(call find_lib,m))
     OS_LDFLAGS += -lm
     $(info using libm: $(call find_lib,m))
@@ -316,14 +515,48 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
     OS_LDFLAGS += -lrt
     $(info using librt: $(call find_lib,rt))
   endif
-  ifneq (,$(call find_lib,pthread))
-    ifneq (,$(call find_include,pthread))
-      OS_CCDEFS += -DUSE_READER_THREAD
-      ifeq (,$(NOASYNCH))
-        OS_CCDEFS += -DSIM_ASYNCH_IO 
-      endif
+  ifneq (,$(call find_include,pthread))
+    ifneq (,$(call find_lib,pthread))
+      OS_CCDEFS += -DUSE_READER_THREAD -DSIM_ASYNCH_IO 
       OS_LDFLAGS += -lpthread
       $(info using libpthread: $(call find_lib,pthread) $(call find_include,pthread))
+    else
+      LIBEXTSAVE := ${LIBEXT}
+      LIBEXT = a
+      ifneq (,$(call find_lib,pthread))
+        OS_CCDEFS += -DUSE_READER_THREAD -DSIM_ASYNCH_IO 
+        OS_LDFLAGS += -lpthread
+        $(info using libpthread: $(call find_lib,pthread) $(call find_include,pthread))
+      else
+        ifneq (,$(findstring Haiku,$(OSTYPE)))
+          OS_CCDEFS += -DUSE_READER_THREAD -DSIM_ASYNCH_IO 
+          $(info using libpthread: $(call find_include,pthread))
+        else
+          ifeq (Darwin,$(OSTYPE))
+            OS_CCDEFS += -DUSE_READER_THREAD -DSIM_ASYNCH_IO 
+            OS_LDFLAGS += -lpthread
+            $(info using macOS libpthread: $(call find_include,pthread))
+          endif
+        endif
+      endif
+      LIBEXT = $(LIBEXTSAVE)
+    endif
+  endif
+  # Find PCRE RegEx library.
+  ifneq (,$(call find_include,pcre))
+    ifneq (,$(call find_lib,pcre))
+      OS_CCDEFS += -DHAVE_PCRE_H
+      OS_LDFLAGS += -lpcre
+      $(info using libpcre: $(call find_lib,pcre) $(call find_include,pcre))
+      ifeq ($(LD_SEARCH_NEEDED),$(call need_search,pcre))
+        OS_LDFLAGS += -L$(dir $(call find_lib,pcre))
+      endif
+    endif
+  endif
+  # Find available ncurses library.
+  ifneq (,$(call find_include,ncurses))
+    ifneq (,$(call find_lib,ncurses))
+      OS_CURSES_DEFS += -DHAVE_NCURSES -lncurses
     endif
   endif
   ifneq (,$(call find_include,semaphore))
@@ -332,24 +565,145 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
       $(info using semaphore: $(call find_include,semaphore))
     endif
   endif
-  ifneq (,$(call find_include,sys/mman))
-    ifneq (,$(shell grep shm_open $(call find_include,sys/mman)))
-      OS_CCDEFS += -DHAVE_SHM_OPEN
-      $(info using mman: $(call find_include,sys/mman))
-    endif
+  ifneq (,$(call find_include,sys/ioctl))
+    OS_CCDEFS += -DHAVE_SYS_IOCTL
+  endif
+  ifneq (,$(call find_include,linux/cdrom))
+    OS_CCDEFS += -DHAVE_LINUX_CDROM
   endif
   ifneq (,$(call find_include,dlfcn))
     ifneq (,$(call find_lib,dl))
-      OS_CCDEFS += -DHAVE_DLOPEN=$(LIBEXT)
+      OS_CCDEFS += -DSIM_HAVE_DLOPEN=${LIBEXT}
       OS_LDFLAGS += -ldl
       $(info using libdl: $(call find_lib,dl) $(call find_include,dlfcn))
     else
-      ifeq (BSD,$(findstring BSD,$(OSTYPE)))
-        OS_CCDEFS += -DHAVE_DLOPEN=so
+      ifneq (,$(findstring BSD,$(OSTYPE))$(findstring AIX,$(OSTYPE))$(findstring Haiku,$(OSTYPE)))
+        OS_CCDEFS += -DSIM_HAVE_DLOPEN=so
         $(info using libdl: $(call find_include,dlfcn))
+      else
+        ifneq (,$(call find_lib,dld))
+          OS_CCDEFS += -DSIM_HAVE_DLOPEN=${LIBEXT}
+          OS_LDFLAGS += -ldld
+          $(info using libdld: $(call find_lib,dld) $(call find_include,dlfcn))
+        else
+          ifeq (Darwin,$(OSTYPE))
+            OS_CCDEFS += -DSIM_HAVE_DLOPEN=dylib
+            $(info using macOS dlopen with .dylib)
+          endif
+        endif
       endif
     endif
   endif
+  ifneq (,$(call find_include,utime))
+    OS_CCDEFS += -DHAVE_UTIME
+  endif
+  ifneq (,$(call find_include,png))
+    ifneq (,$(call find_lib,png))
+      OS_CCDEFS += -DHAVE_LIBPNG
+      OS_LDFLAGS += -lpng
+      $(info using libpng: $(call find_lib,png) $(call find_include,png))
+      ifneq (,$(call find_include,zlib))
+        ifneq (,$(call find_lib,z))
+          OS_CCDEFS += -DHAVE_ZLIB
+          OS_LDFLAGS += -lz
+          $(info using zlib: $(call find_lib,z) $(call find_include,zlib))
+        endif
+      endif
+    endif
+  endif
+  ifneq (,$(call find_include,glob))
+    OS_CCDEFS += -DHAVE_GLOB
+  else
+    ifneq (,$(call find_include,fnmatch))
+      OS_CCDEFS += -DHAVE_FNMATCH    
+    endif
+  endif
+  ifneq (,$(call find_include,sys/mman))
+    ifneq (,$(shell grep shm_open $(call find_include,sys/mman)))
+      # some Linux installs have been known to have the include, but are
+      # missing librt (where the shm_ APIs are implemented on Linux)
+      # other OSes seem have these APIs implemented elsewhere
+      ifneq (,$(if $(findstring Linux,$(OSTYPE)),$(call find_lib,rt),OK))
+        OS_CCDEFS += -DHAVE_SHM_OPEN
+        $(info using mman: $(call find_include,sys/mman))
+      endif
+    endif
+  endif
+  ifneq (,$(VIDEO_USEFUL))
+    ifeq (cygwin,$(OSTYPE))
+      LIBEXTSAVE := ${LIBEXT}
+      LIBEXT = dll.a
+    endif
+    ifneq (,$(call find_include,SDL2/SDL))
+      ifneq (,$(call find_lib,SDL2))
+        ifneq (,$(findstring Haiku,$(OSTYPE)))
+          ifneq (,$(shell which sdl2-config))
+            SDLX_CONFIG = sdl2-config
+          endif
+        else
+          SDLX_CONFIG = $(realpath $(dir $(call find_include,SDL2/SDL))../../bin/sdl2-config)
+        endif
+        ifneq (,$(SDLX_CONFIG))
+          VIDEO_CCDEFS += -DHAVE_LIBSDL -DUSE_SIM_VIDEO `$(SDLX_CONFIG) --cflags`
+          VIDEO_LDFLAGS += `$(SDLX_CONFIG) --libs`
+          VIDEO_FEATURES = - video capabilities provided by libSDL2 (Simple Directmedia Layer)
+          DISPLAYL = ${DISPLAYD}/display.c $(DISPLAYD)/sim_ws.c
+          DISPLAYVT = ${DISPLAYD}/vt11.c
+          DISPLAY340 = ${DISPLAYD}/type340.c
+          DISPLAYNG = ${DISPLAYD}/ng.c
+          DISPLAYIII = ${DISPLAYD}/iii.c
+          DISPLAY_OPT += -DUSE_DISPLAY $(VIDEO_CCDEFS) $(VIDEO_LDFLAGS)
+          $(info using libSDL2: $(call find_include,SDL2/SDL))
+          ifeq (Darwin,$(OSTYPE))
+            VIDEO_CCDEFS += -DSDL_MAIN_AVAILABLE
+          endif
+        endif
+      endif
+    endif
+    ifeq (cygwin,$(OSTYPE))
+      LIBEXT = $(LIBEXTSAVE)
+    endif
+    ifeq (,$(findstring HAVE_LIBSDL,$(VIDEO_CCDEFS)))
+      $(info *** Info ***)
+      $(info *** Info *** The simulator$(BUILD_MULTIPLE) you are building could provide more functionality)
+      $(info *** Info *** if video support was available on your system.)
+      $(info *** Info *** To gain this functionality:)
+      ifeq (Darwin,$(OSTYPE))
+        ifeq (/opt/local/bin/port,$(shell which port))
+          $(info *** Info *** Install the MacPorts libSDL2 package to provide this)
+          $(info *** Info *** functionality for your OS X system:)
+          $(info *** Info ***       # port install libsdl2 libpng zlib)
+        endif
+        ifeq (/usr/local/bin/brew,$(shell which brew))
+          ifeq (/opt/local/bin/port,$(shell which port))
+            $(info *** Info ***)
+            $(info *** Info *** OR)
+            $(info *** Info ***)
+          endif
+          $(info *** Info *** Install the HomeBrew libSDL2 package to provide this)
+          $(info *** Info *** functionality for your OS X system:)
+          $(info *** Info ***       $$ brew install sdl2 libpng zlib)
+        else
+          ifeq (,$(shell which port))
+            $(info *** Info *** Install MacPorts or HomeBrew and rerun this make for)
+            $(info *** Info *** specific advice)
+          endif
+        endif
+      else
+        ifneq (,$(and $(findstring Linux,$(OSTYPE)),$(call find_exe,apt-get)))
+          $(info *** Info *** Install the development components of libSDL2 packaged for)
+          $(info *** Info *** your operating system distribution for your Linux)
+          $(info *** Info *** system:)
+          $(info *** Info ***        $$ sudo apt-get install libsdl2-dev libpng-dev)
+        else
+          $(info *** Info *** Install the development components of libSDL2 packaged by your)
+          $(info *** Info *** operating system distribution and rebuild your simulator to)
+          $(info *** Info *** enable this extra functionality.)
+        endif
+      endif
+      $(info *** Info ***)
+    endif
+  endif
   ifneq (,$(NETWORK_USEFUL))
     ifneq (,$(call find_include,pcap))
       ifneq (,$(shell grep 'pcap/pcap.h' $(call find_include,pcap) | grep include))
@@ -360,9 +714,29 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
       ifneq (,$(shell grep pcap_compile $(PCAP_H_PATH) | grep const))
         BPF_CONST_STRING = -DBPF_CONST_STRING
       endif
+      NETWORK_CCDEFS += -DHAVE_PCAP_NETWORK -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING)
+      NETWORK_LAN_FEATURES += PCAP
       ifneq (,$(call find_lib,$(PCAPLIB)))
         ifneq ($(USE_NETWORK),) # Network support specified on the GNU make command line
-          NETWORK_CCDEFS = -DUSE_NETWORK -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING)
+          NETWORK_CCDEFS += -DUSE_NETWORK
+          ifeq (,$(findstring Linux,$(OSTYPE))$(findstring Darwin,$(OSTYPE)))
+            $(info *** Warning ***)
+            $(info *** Warning *** Statically linking against libpcap is provides no measurable)
+            $(info *** Warning *** benefits over dynamically linking libpcap.)
+            $(info *** Warning ***)
+            $(info *** Warning *** Support for linking this way is currently deprecated and may be removed)
+            $(info *** Warning *** in the future.)
+            $(info *** Warning ***)
+          else
+            $(info *** Error ***)
+            $(info *** Error *** Statically linking against libpcap is provides no measurable)
+            $(info *** Error *** benefits over dynamically linking libpcap.)
+            $(info *** Error ***)
+            $(info *** Error *** Support for linking statically has been removed on the $(OSTYPE))
+            $(info *** Error *** platform.)
+            $(info *** Error ***)
+            $(error Retry your build without specifying USE_NETWORK=1)
+          endif
           ifeq (cygwin,$(OSTYPE))
             # cygwin has no ldconfig so explicitly specify pcap object library
             NETWORK_LDFLAGS = -L$(dir $(call find_lib,$(PCAPLIB))) -Wl,-R,$(dir $(call find_lib,$(PCAPLIB))) -l$(PCAPLIB)
@@ -372,71 +746,196 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
           $(info using libpcap: $(call find_lib,$(PCAPLIB)) $(call find_include,pcap))
           NETWORK_FEATURES = - static networking support using $(OSNAME) provided libpcap components
         else # default build uses dynamic libpcap
-          NETWORK_CCDEFS = -DUSE_SHARED -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING)
+          NETWORK_CCDEFS += -DUSE_SHARED
           $(info using libpcap: $(call find_include,pcap))
           NETWORK_FEATURES = - dynamic networking support using $(OSNAME) provided libpcap components
         endif
       else
-        NETWORK_CCDEFS = -DUSE_SHARED -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING)
-        NETWORK_FEATURES = - dynamic networking support using $(OSNAME) provided libpcap components
-        $(info using libpcap: $(call find_include,pcap))
+        LIBEXTSAVE := ${LIBEXT}
+        LIBEXT = a
+        ifneq (,$(call find_lib,$(PCAPLIB)))
+          NETWORK_CCDEFS += -DUSE_NETWORK
+          NETWORK_LDFLAGS := -L$(dir $(call find_lib,$(PCAPLIB))) -l$(PCAPLIB)
+          NETWORK_FEATURES = - static networking support using $(OSNAME) provided libpcap components
+          $(info using libpcap: $(call find_lib,$(PCAPLIB)) $(call find_include,pcap))
+        endif
+        LIBEXT = $(LIBEXTSAVE)
+        ifeq (Darwin,$(OSTYPE)$(findstring USE_,$(NETWORK_CCDEFS)))
+          NETWORK_CCDEFS += -DUSE_SHARED
+          NETWORK_FEATURES = - dynamic networking support using $(OSNAME) provided libpcap components
+          $(info using macOS dynamic libpcap: $(call find_include,pcap))
+        endif
       endif
     else
-      # Look for package built from tcpdump.org sources with default install target (or cygwin winpcap)
-      LIBPATH += /usr/local/lib
-      INCPATH += /usr/local/include
-      LIBEXTSAVE := $(LIBEXT)
-      LIBEXT = a
-      ifneq (,$(call find_lib,$(PCAPLIB)))
-        ifneq (,$(call find_include,pcap))
-          $(info using libpcap: $(call find_lib,$(PCAPLIB)) $(call find_include,pcap))
-          ifeq (cygwin,$(OSTYPE))
-            NETWORK_CCDEFS = -DUSE_NETWORK -I$(dir $(call find_include,pcap))
-            NETWORK_LDFLAGS = -L$(dir $(call find_lib,$(PCAPLIB))) -Wl,-R,$(dir $(call find_lib,$(PCAPLIB))) -l$(PCAPLIB)
-            NETWORK_FEATURES = - static networking support using libpcap components located in the cygwin directories
+      # On non-Linux platforms, we'll still try to provide deprecated support for libpcap in /usr/local
+      INCPATHSAVE := ${INCPATH}
+      ifeq (,$(findstring Linux,$(OSTYPE)))
+        # Look for package built from tcpdump.org sources with default install target (or cygwin winpcap)
+        INCPATH += /usr/local/include
+        PCAP_H_FOUND = $(call find_include,pcap)
+      endif
+      ifneq (,$(strip $(PCAP_H_FOUND)))
+        ifneq (,$(shell grep 'pcap/pcap.h' $(call find_include,pcap) | grep include))
+          PCAP_H_PATH = $(dir $(call find_include,pcap))pcap/pcap.h
+        else
+          PCAP_H_PATH = $(call find_include,pcap)
+        endif
+        ifneq (,$(shell grep pcap_compile $(PCAP_H_PATH) | grep const))
+          BPF_CONST_STRING = -DBPF_CONST_STRING
+        endif
+        LIBEXTSAVE := ${LIBEXT}
+        # first check if binary - shared objects are available/installed in the linker known search paths
+        ifneq (,$(call find_lib,$(PCAPLIB)))
+          NETWORK_CCDEFS = -DUSE_SHARED -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING)
+          NETWORK_FEATURES = - dynamic networking support using libpcap components from www.tcpdump.org and locally installed libpcap.${LIBEXT}
+          $(info using libpcap: $(call find_include,pcap))
+        else
+          LIBPATH += /usr/local/lib
+          LIBEXT = a
+          ifneq (,$(call find_lib,$(PCAPLIB)))
+            $(info using libpcap: $(call find_lib,$(PCAPLIB)) $(call find_include,pcap))
+            ifeq (cygwin,$(OSTYPE))
+              NETWORK_CCDEFS = -DUSE_NETWORK -DHAVE_PCAP_NETWORK -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING)
+              NETWORK_LDFLAGS = -L$(dir $(call find_lib,$(PCAPLIB))) -Wl,-R,$(dir $(call find_lib,$(PCAPLIB))) -l$(PCAPLIB)
+              NETWORK_FEATURES = - static networking support using libpcap components located in the cygwin directories
+            else
+              NETWORK_CCDEFS := -DUSE_NETWORK -DHAVE_PCAP_NETWORK -isystem -I$(dir $(call find_include,pcap)) $(BPF_CONST_STRING) $(call find_lib,$(PCAPLIB))
+              NETWORK_FEATURES = - networking support using libpcap components from www.tcpdump.org
+              $(info *** Warning ***)
+              $(info *** Warning *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) being built with networking support using)
+              $(info *** Warning *** libpcap components from www.tcpdump.org.)
+              $(info *** Warning *** Some users have had problems using the www.tcpdump.org libpcap)
+              $(info *** Warning *** components for simh networking.  For best results, with)
+              $(info *** Warning *** simh networking, it is recommended that you install the)
+              $(info *** Warning *** libpcap-dev (or libpcap-devel) package from your $(OSNAME) distribution)
+              $(info *** Warning ***)
+              $(info *** Warning *** Building with the components manually installed from www.tcpdump.org)
+              $(info *** Warning *** is officially deprecated.  Attempting to do so is unsupported.)
+              $(info *** Warning ***)
+            endif
           else
-            NETWORK_CCDEFS := -DUSE_NETWORK -isystem $(dir $(call find_include,pcap)) $(call find_lib,$(PCAPLIB))
-            NETWORK_FEATURES = - networking support using libpcap components from www.tcpdump.org
-            $(info *** Warning ***)
-            $(info *** Warning *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) being built with networking support using)
-            $(info *** Warning *** libpcap components from www.tcpdump.org.)
-            $(info *** Warning *** Some users have had problems using the www.tcpdump.org libpcap)
-            $(info *** Warning *** components for simh networking.  For best results, with)
-            $(info *** Warning *** simh networking, it is recommended that you install the)
-            $(info *** Warning *** libpcap-dev package from your $(OSTYPE) distribution)
-            $(info *** Warning ***)
+            $(error using libpcap: $(call find_include,pcap) missing $(PCAPLIB).${LIBEXT})
+          endif
+          NETWORK_LAN_FEATURES += PCAP
+        endif
+        LIBEXT = $(LIBEXTSAVE)
+      else
+        INCPATH = $(INCPATHSAVE)
+        $(info *** Warning ***)
+        $(info *** Warning *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) $(BUILD_MULTIPLE_VERB) being built WITHOUT)
+        $(info *** Warning *** libpcap networking support)
+        $(info *** Warning ***)
+        $(info *** Warning *** To build simulator(s) with libpcap networking support you)
+        ifneq (,$(and $(findstring Linux,$(OSTYPE)),$(call find_exe,apt-get)))
+          $(info *** Warning *** should install the libpcap development components for)
+          $(info *** Warning *** for your Linux system:)
+          $(info *** Warning ***        $$ sudo apt-get install libpcap-dev)
+        else
+          $(info *** Warning *** should read 0readme_ethernet.txt and follow the instructions)
+          $(info *** Warning *** regarding the needed libpcap development components for your)
+          $(info *** Warning *** $(OSTYPE) platform)
+        endif
+        $(info *** Warning ***)
+      endif
+    endif
+    # Consider other network connections
+    ifneq (,$(call find_lib,vdeplug))
+      # libvdeplug requires the use of the OS provided libpcap
+      ifeq (,$(findstring usr/local,$(NETWORK_CCDEFS)))
+        ifneq (,$(call find_include,libvdeplug))
+          # Provide support for vde networking
+          NETWORK_CCDEFS += -DHAVE_VDE_NETWORK
+          NETWORK_LAN_FEATURES += VDE
+          ifeq (,$(findstring USE_NETWORK,$(NETWORK_CCDEFS))$(findstring USE_SHARED,$(NETWORK_CCDEFS)))
+            NETWORK_CCDEFS += -DUSE_NETWORK
+          endif
+          ifeq (Darwin,$(OSTYPE))
+            NETWORK_LDFLAGS += -lvdeplug -L$(dir $(call find_lib,vdeplug))
+          else
+            NETWORK_LDFLAGS += -lvdeplug -Wl,-R,$(dir $(call find_lib,vdeplug)) -L$(dir $(call find_lib,vdeplug))
+          endif
+          $(info using libvdeplug: $(call find_lib,vdeplug) $(call find_include,libvdeplug))
+        endif
+      endif
+    endif
+    ifeq (,$(findstring HAVE_VDE_NETWORK,$(NETWORK_CCDEFS)))
+      # Support is available on Linux for libvdeplug.  Advise on its usage
+      ifneq (,$(findstring Linux,$(OSTYPE))$(findstring Darwin,$(OSTYPE)))
+        ifneq (,$(findstring USE_NETWORK,$(NETWORK_CCDEFS))$(findstring USE_SHARED,$(NETWORK_CCDEFS)))
+          $(info *** Info ***)
+          $(info *** Info *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) $(BUILD_MULTIPLE_VERB) being built with)
+          $(info *** Info *** minimal libpcap networking support)
+          $(info *** Info ***)
+        endif
+        $(info *** Info ***)
+        $(info *** Info *** Simulators on your $(OSNAME) platform can also be built with)
+        $(info *** Info *** extended LAN Ethernet networking support by using VDE Ethernet.)
+        $(info *** Info ***)
+        $(info *** Info *** To build simulator(s) with extended networking support you)
+        ifeq (Darwin,$(OSTYPE))
+          ifeq (/opt/local/bin/port,$(shell which port))
+            $(info *** Info *** should install the MacPorts vde2 package to provide this)
+            $(info *** Info *** functionality for your OS X system:)
+            $(info *** Info ***       # port install vde2)
+          endif
+          ifeq (/usr/local/bin/brew,$(shell which brew))
+            ifeq (/opt/local/bin/port,$(shell which port))
+              $(info *** Info ***)
+              $(info *** Info *** OR)
+              $(info *** Info ***)
+            endif
+            $(info *** Info *** should install the HomeBrew vde package to provide this)
+            $(info *** Info *** functionality for your OS X system:)
+            $(info *** Info ***       $$ brew install vde)
+          else
+            ifeq (,$(shell which port))
+              $(info *** Info *** should install MacPorts or HomeBrew and rerun this make for)
+              $(info *** Info *** specific advice)
+            endif
           endif
         else
-          $(error using libpcap: $(call find_lib,$(PCAPLIB)) missing pcap.h)
-        endif
-      endif
-      LIBEXT = $(LIBEXTSAVE)
-    endif
-    ifneq (,$(findstring USE_NETWORK,$(NETWORK_CCDEFS))$(findstring USE_SHARED,$(NETWORK_CCDEFS)))
-      # Given we have libpcap components, consider other network connections as well
-      ifneq (,$(call find_lib,vdeplug))
-        # libvdeplug requires the use of the OS provided libpcap
-        ifeq (,$(findstring usr/local,$(NETWORK_CCDEFS)))
-          ifneq (,$(call find_include,libvdeplug))
-            # Provide support for vde networking
-            NETWORK_CCDEFS += -DUSE_VDE_NETWORK
-            NETWORK_LDFLAGS += -lvdeplug
-            $(info using libvdeplug: $(call find_lib,vdeplug) $(call find_include,libvdeplug))
+          ifneq (,$(and $(findstring Linux,$(OSTYPE)),$(call find_exe,apt-get)))
+            $(info *** Info *** should install the vde2 package to provide this)
+            $(info *** Info *** functionality for your $(OSNAME) system:)
+            ifneq (,$(shell apt list 2>/dev/null| grep libvdeplug-dev))
+              $(info *** Info ***        $$ sudo apt-get install libvdeplug-dev)
+            else
+              $(info *** Info ***        $$ sudo apt-get install vde2)
+            endif
+          else
+            $(info *** Info *** should read 0readme_ethernet.txt and follow the instructions)
+            $(info *** Info *** regarding the needed libvdeplug components for your $(OSNAME))
+            $(info *** Info *** platform)
           endif
         endif
+        $(info *** Info ***)
       endif
-      ifneq (,$(call find_include,linux/if_tun))
-        # Provide support for Tap networking on Linux
-        NETWORK_CCDEFS += -DUSE_TAP_NETWORK
+    endif
+    ifneq (,$(call find_include,linux/if_tun))
+      # Provide support for Tap networking on Linux
+      NETWORK_CCDEFS += -DHAVE_TAP_NETWORK
+      NETWORK_LAN_FEATURES += TAP
+      ifeq (,$(findstring USE_NETWORK,$(NETWORK_CCDEFS))$(findstring USE_SHARED,$(NETWORK_CCDEFS)))
+        NETWORK_CCDEFS += -DUSE_NETWORK
       endif
-      ifeq (bsdtuntap,$(shell if $(TEST) -e /usr/include/net/if_tun.h -o -e /Library/Extensions/tap.kext; then echo bsdtuntap; fi))
-        # Provide support for Tap networking on BSD platforms (including OS X)
-        NETWORK_CCDEFS += -DUSE_TAP_NETWORK -DUSE_BSDTUNTAP
+    endif
+    ifeq (bsdtuntap,$(shell if ${TEST} -e /usr/include/net/if_tun.h -o -e /Library/Extensions/tap.kext -o -e /Applications/Tunnelblick.app/Contents/Resources/tap-notarized.kext; then echo bsdtuntap; fi))
+      # Provide support for Tap networking on BSD platforms (including OS X)
+      NETWORK_CCDEFS += -DHAVE_TAP_NETWORK -DHAVE_BSDTUNTAP
+      NETWORK_LAN_FEATURES += TAP
+      ifeq (,$(findstring USE_NETWORK,$(NETWORK_CCDEFS))$(findstring USE_SHARED,$(NETWORK_CCDEFS)))
+        NETWORK_CCDEFS += -DUSE_NETWORK
       endif
-    else
-      NETWORK_FEATURES = - WITHOUT networking support
+    endif
+    ifeq (slirp,$(shell if ${TEST} -e slirp_glue/sim_slirp.c; then echo slirp; fi))
+      NETWORK_CCDEFS += -Islirp -Islirp_glue -Islirp_glue/qemu -DHAVE_SLIRP_NETWORK -DUSE_SIMH_SLIRP_DEBUG slirp/*.c slirp_glue/*.c
+      NETWORK_LAN_FEATURES += NAT(SLiRP)
+    endif
+    ifeq (,$(findstring USE_NETWORK,$(NETWORK_CCDEFS))$(findstring USE_SHARED,$(NETWORK_CCDEFS))$(findstring HAVE_VDE_NETWORK,$(NETWORK_CCDEFS)))
+      NETWORK_CCDEFS += -DUSE_NETWORK
+      NETWORK_FEATURES = - WITHOUT Local LAN networking support
       $(info *** Warning ***)
-      $(info *** Warning *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) are being built WITHOUT networking support)
+      $(info *** Warning *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) $(BUILD_MULTIPLE_VERB) being built WITHOUT LAN networking support)
       $(info *** Warning ***)
       $(info *** Warning *** To build simulator(s) with networking support you should read)
       $(info *** Warning *** 0readme_ethernet.txt and follow the instructions regarding the)
@@ -445,70 +944,276 @@ ifeq ($(WIN32),)  #*nix Environments (&& cygwin)
     endif
     NETWORK_OPT = $(NETWORK_CCDEFS)
   endif
-  ifneq (binexists,$(shell if $(TEST) -e BIN; then echo binexists; fi))
-    MKDIRBIN = if $(TEST) ! -e BIN; then mkdir BIN; fi
+  ifneq (binexists,$(shell if ${TEST} -e BIN/buildtools; then echo binexists; fi))
+    MKDIRBIN = @mkdir -p BIN/buildtools
+  endif
+  ifeq (commit-id-exists,$(shell if ${TEST} -e .git-commit-id; then echo commit-id-exists; fi))
+    GIT_COMMIT_ID=$(shell grep 'SIM_GIT_COMMIT_ID' .git-commit-id | awk '{ print $$2 }')
+    GIT_COMMIT_TIME=$(shell grep 'SIM_GIT_COMMIT_TIME' .git-commit-id | awk '{ print $$2 }')
+  else
+    ifeq (,$(shell grep 'define SIM_GIT_COMMIT_ID' sim_rev.h | grep 'Format:'))
+      GIT_COMMIT_ID=$(shell grep 'define SIM_GIT_COMMIT_ID' sim_rev.h | awk '{ print $$3 }')
+      GIT_COMMIT_TIME=$(shell grep 'define SIM_GIT_COMMIT_TIME' sim_rev.h | awk '{ print $$3 }')
+    else
+      ifeq (git-submodule,$(if $(shell cd .. ; git rev-parse --git-dir 2>/dev/null),git-submodule))
+        GIT_COMMIT_ID=$(shell cd .. ; git submodule status | grep " $(notdir $(realpath .)) " | awk '{ print $$1 }')
+        GIT_COMMIT_TIME=$(shell git --git-dir=$(realpath .)/.git log $(GIT_COMMIT_ID) -1 --pretty="%aI")
+      else
+        $(info *** Error ***)
+        $(info *** Error *** The simh git commit id can not be determined.)
+        $(info *** Error ***)
+        $(info *** Error *** There are ONLY two supported ways to acquire and build)
+        $(info *** Error *** the simh source code:)
+        $(info *** Error ***   1: directly with git via:)
+        $(info *** Error ***      $$ git clone https://github.com/simh/simh)
+        $(info *** Error ***      $$ cd simh)
+        $(info *** Error ***      $$ make {simulator-name})
+        $(info *** Error *** OR)
+        $(info *** Error ***   2: download the source code zip archive from:)
+        $(info *** Error ***      $$ wget(or via browser) https://github.com/simh/simh/archive/master.zip)
+        $(info *** Error ***      $$ unzip master.zip)
+        $(info *** Error ***      $$ cd simh-master)
+        $(info *** Error ***      $$ make {simulator-name})
+        $(info *** Error ***)
+        $(error get simh source either with zip download or git clone)
+      endif
+    endif
   endif
 else
   #Win32 Environments (via MinGW32)
-  GCC = gcc
-  GCC_Path := $(dir $(shell where gcc.exe))
-  GCC_VERSION = $(word 3,$(shell $(GCC) --version))
-  LTO_EXCLUDE_VERSIONS = 4.5.2
-  ifeq (pthreads,$(shell if exist ..\windows-build\pthreads\Pre-built.2\include\pthread.h echo pthreads))
-    PTHREADS_CCDEFS = -DUSE_READER_THREAD -DPTW32_STATIC_LIB -D_POSIX_C_SOURCE -I../windows-build/pthreads/Pre-built.2/include
-    ifeq (,$(NOASYNCH))
-      PTHREADS_CCDEFS += -DSIM_ASYNCH_IO 
-    endif
-    PTHREADS_LDFLAGS = -lpthreadGC2 -L..\windows-build\pthreads\Pre-built.2\lib
+  GCC := gcc
+  GCC_Path := $(abspath $(dir $(word 1,$(wildcard $(addsuffix /${GCC}.exe,$(subst ;, ,${PATH}))))))
+  ifeq (rename-build-support,$(shell if exist ..\windows-build-windows-build echo rename-build-support))
+    REMOVE_OLD_BUILD := $(shell if exist ..\windows-build rmdir/s/q ..\windows-build)
+    FIXED_BUILD := $(shell move ..\windows-build-windows-build ..\windows-build >NUL)
+  endif
+  GCC_VERSION = $(word 3,$(shell ${GCC} --version))
+  COMPILER_NAME = GCC Version: $(GCC_VERSION)
+  ifeq (,$(findstring ++,${GCC}))
+    CC_STD = -std=gnu99
   else
-    ifeq (pthreads,$(shell if exist $(dir $(GCC_Path))..\include\pthread.h echo pthreads))
-      PTHREADS_CCDEFS = -DUSE_READER_THREAD
-      ifeq (,$(NOASYNCH))
-        PTHREADS_CCDEFS += -DSIM_ASYNCH_IO 
-      endif
-      PTHREADS_LDFLAGS = -lpthread
+    CPP_BUILD = 1
+  endif
+  LTO_EXCLUDE_VERSIONS = 4.5.2
+  ifeq (,$(PATH_SEPARATOR))
+    PATH_SEPARATOR := ;
+  endif
+  INCPATH = $(abspath $(wildcard $(GCC_Path)\..\include $(subst $(PATH_SEPARATOR), ,$(CPATH))  $(subst $(PATH_SEPARATOR), ,$(C_INCLUDE_PATH))))
+  LIBPATH = $(abspath $(wildcard $(GCC_Path)\..\lib $(subst :, ,$(LIBRARY_PATH))))
+  $(info lib paths are: ${LIBPATH})
+  $(info include paths are: ${INCPATH})
+  # Give preference to any MinGW provided threading (if available)
+  ifneq (,$(call find_include,pthread))
+    PTHREADS_CCDEFS = -DUSE_READER_THREAD -DSIM_ASYNCH_IO
+    PTHREADS_LDFLAGS = -lpthread
+  else
+    ifeq (pthreads,$(shell if exist ..\windows-build\pthreads\Pre-built.2\include\pthread.h echo pthreads))
+      PTHREADS_CCDEFS = -DUSE_READER_THREAD -DPTW32_STATIC_LIB -D_POSIX_C_SOURCE -I../windows-build/pthreads/Pre-built.2/include -DSIM_ASYNCH_IO
+      PTHREADS_LDFLAGS = -lpthreadGC2 -L..\windows-build\pthreads\Pre-built.2\lib
     endif
   endif
   ifeq (pcap,$(shell if exist ..\windows-build\winpcap\Wpdpack\include\pcap.h echo pcap))
-    PCAP_CCDEFS = -I../windows-build/winpcap/Wpdpack/include -I$(GCC_Path)..\include\ddk -DUSE_SHARED
     NETWORK_LDFLAGS =
-    NETWORK_OPT = -DUSE_SHARED
+    NETWORK_OPT = -DUSE_SHARED -I../windows-build/winpcap/Wpdpack/include
     NETWORK_FEATURES = - dynamic networking support using windows-build provided libpcap components
+    NETWORK_LAN_FEATURES += PCAP
   else
-    ifeq (pcap,$(shell if exist $(dir $(GCC_Path))..\include\pcap.h echo pcap))
-      PCAP_CCDEFS = -DUSE_SHARED -I$(GCC_Path)..\include\ddk
+    ifneq (,$(call find_include,pcap))
       NETWORK_LDFLAGS =
       NETWORK_OPT = -DUSE_SHARED
       NETWORK_FEATURES = - dynamic networking support using libpcap components found in the MinGW directories
+      NETWORK_LAN_FEATURES += PCAP
     endif
   endif
-  OS_CCDEFS =  -fms-extensions $(PTHREADS_CCDEFS) $(PCAP_CCDEFS)
-  OS_LDFLAGS = -lm -lwsock32 -lwinmm $(PTHREADS_LDFLAGS)
+  ifneq (,$(VIDEO_USEFUL))
+    SDL_INCLUDE = $(word 1,$(shell dir /b /s ..\windows-build\libSDL\SDL.h))
+    ifeq (SDL.h,$(findstring SDL.h,$(SDL_INCLUDE)))
+      VIDEO_CCDEFS += -DHAVE_LIBSDL -DUSE_SIM_VIDEO -I$(abspath $(dir $(SDL_INCLUDE)))
+      ifneq ($(DEBUG),)
+        VIDEO_LDFLAGS  += $(abspath $(dir $(SDL_INCLUDE))\..\..\..\lib\lib-VC2008\Debug)/SDL2.lib
+      else
+        VIDEO_LDFLAGS  += $(abspath $(dir $(SDL_INCLUDE))\..\..\..\lib\lib-VC2008\Release)/SDL2.lib
+      endif
+      VIDEO_FEATURES = - video capabilities provided by libSDL2 (Simple Directmedia Layer)
+      DISPLAYL = ${DISPLAYD}/display.c $(DISPLAYD)/sim_ws.c
+      DISPLAYVT = ${DISPLAYD}/vt11.c
+      DISPLAY340 = ${DISPLAYD}/type340.c
+      DISPLAYNG = ${DISPLAYD}/ng.c
+      DISPLAY_OPT += -DUSE_DISPLAY $(VIDEO_CCDEFS) $(VIDEO_LDFLAGS)
+    else
+      $(info ***********************************************************************)
+      $(info ***********************************************************************)
+      $(info **  This build could produce simulators with video capabilities.     **)
+      $(info **  However, the required files to achieve this can't be found on    **)
+      $(info **  this system.  Download the file:                                 **)
+      $(info **  https://github.com/simh/windows-build/archive/windows-build.zip  **)
+      $(info **  Extract the windows-build-windows-build folder it contains to    **)
+      $(info **  $(abspath ..\)                                                   **)
+      $(info ***********************************************************************)
+      $(info ***********************************************************************)
+      $(info .)
+    endif
+  endif
+  OS_CCDEFS += -fms-extensions $(PTHREADS_CCDEFS)
+  OS_LDFLAGS += -lm -lwsock32 -lwinmm $(PTHREADS_LDFLAGS)
   EXE = .exe
-  ifneq (binexists,$(shell if exist BIN echo binexists))
-    MKDIRBIN = if not exist BIN mkdir BIN
+  ifneq (clean,${MAKECMDGOALS})
+    ifneq (buildtoolsexists,$(shell if exist BIN\buildtools (echo buildtoolsexists) else (mkdir BIN\buildtools)))
+      MKDIRBIN=
+    endif
   endif
   ifneq ($(USE_NETWORK),)
-    NETWORK_OPT = -DUSE_SHARED
+    NETWORK_OPT += -DUSE_SHARED
   endif
+  ifeq (git-repo,$(shell if exist .git echo git-repo))
+    GIT_PATH := $(shell where git)
+    ifeq (,$(GIT_PATH))
+      $(error building using a git repository, but git is not available)
+    endif
+    ifeq (commit-id-exists,$(shell if exist .git-commit-id echo commit-id-exists))
+      CURRENT_GIT_COMMIT_ID=$(shell for /F "tokens=2" %%i in ("$(shell findstr /C:"SIM_GIT_COMMIT_ID" .git-commit-id)") do echo %%i)
+      ifneq (, $(shell git update-index --refresh --))
+        ACTUAL_GIT_COMMIT_EXTRAS=+uncommitted-changes
+      endif
+      ACTUAL_GIT_COMMIT_ID=$(strip $(shell git log -1 --pretty=%H))$(ACTUAL_GIT_COMMIT_EXTRAS)
+      ifneq ($(CURRENT_GIT_COMMIT_ID),$(ACTUAL_GIT_COMMIT_ID))
+        NEED_COMMIT_ID = need-commit-id
+        # make sure that the invalidly formatted .git-commit-id file wasn't generated
+        # by legacy git hooks which need to be removed.
+        $(shell if exist .git\hooks\post-checkout del .git\hooks\post-checkout)
+        $(shell if exist .git\hooks\post-commit   del .git\hooks\post-commit)
+        $(shell if exist .git\hooks\post-merge    del .git\hooks\post-merge)
+      endif
+    else
+      NEED_COMMIT_ID = need-commit-id
+    endif
+    ifeq (need-commit-id,$(NEED_COMMIT_ID))
+      ifneq (, $(shell git update-index --refresh --))
+        ACTUAL_GIT_COMMIT_EXTRAS=+uncommitted-changes
+      endif
+      ACTUAL_GIT_COMMIT_ID=$(strip $(shell git log -1 --pretty=%H))$(ACTUAL_GIT_COMMIT_EXTRAS)
+      isodate=$(shell git log -1 --pretty=%ai)
+      commit_time=$(word 1,$(isodate))T$(word 2,$(isodate))$(word 3,$(isodate))
+      $(shell echo SIM_GIT_COMMIT_ID $(ACTUAL_GIT_COMMIT_ID)>.git-commit-id)
+      $(shell echo SIM_GIT_COMMIT_TIME $(commit_time)>>.git-commit-id)
+    endif
+  endif
+  ifneq (,$(shell if exist .git-commit-id echo git-commit-id))
+    GIT_COMMIT_ID=$(shell for /F "tokens=2" %%i in ("$(shell findstr /C:"SIM_GIT_COMMIT_ID" .git-commit-id)") do echo %%i)
+    GIT_COMMIT_TIME=$(shell for /F "tokens=2" %%i in ("$(shell findstr /C:"SIM_GIT_COMMIT_TIME" .git-commit-id)") do echo %%i)
+  else
+    ifeq (,$(shell findstr /C:"define SIM_GIT_COMMIT_ID" sim_rev.h | findstr Format))
+      GIT_COMMIT_ID=$(shell for /F "tokens=3" %%i in ("$(shell findstr /C:"define SIM_GIT_COMMIT_ID" sim_rev.h)") do echo %%i)
+      GIT_COMMIT_TIME=$(shell for /F "tokens=3" %%i in ("$(shell findstr /C:"define SIM_GIT_COMMIT_TIME" sim_rev.h)") do echo %%i)
+    endif
+  endif
+  ifneq (windows-build,$(shell if exist ..\windows-build\README.md echo windows-build))
+    ifneq (,$(GIT_PATH))
+      $(info Cloning the windows-build dependencies into $(abspath ..)/windows-build)
+      $(shell git clone https://github.com/simh/windows-build ../windows-build)
+    else
+      $(info ***********************************************************************)
+      $(info ***********************************************************************)
+      $(info **  This build is operating without the required windows-build       **)
+      $(info **  components and therefore will produce less than optimal          **)
+      $(info **  simulator operation and features.                                **)
+      $(info **  Download the file:                                               **)
+      $(info **  https://github.com/simh/windows-build/archive/windows-build.zip  **)
+      $(info **  Extract the windows-build-windows-build folder it contains to    **)
+      $(info **  $(abspath ..\)                                                   **)
+      $(info ***********************************************************************)
+      $(info ***********************************************************************)
+      $(info .)
+    endif
+  else
+    # Version check on windows-build
+    WINDOWS_BUILD = $(word 2,$(shell findstr WINDOWS-BUILD ..\windows-build\Windows-Build_Versions.txt))
+    ifeq (,$(WINDOWS_BUILD))
+      WINDOWS_BUILD = 00000000
+    endif
+    ifneq (,$(or $(shell if 20190124 GTR $(WINDOWS_BUILD) echo old-windows-build),$(and $(shell if 20171112 GTR $(WINDOWS_BUILD) echo old-windows-build),$(findstring pthreadGC2,$(PTHREADS_LDFLAGS)))))
+      $(info .)
+      $(info windows-build components at: $(abspath ..\windows-build))
+      $(info .)
+      $(info ***********************************************************************)
+      $(info ***********************************************************************)
+      $(info **  This currently available windows-build components are out of     **)
+      ifneq (,$(GIT_PATH))
+        $(info **  date.  You need to update to the latest windows-build            **)
+        $(info **  dependencies by executing these commands:                        **)
+        $(info **                                                                   **)
+        $(info **    > cd ..\windows-build                                          **)
+        $(info **    > git pull                                                     **)
+        $(info **                                                                   **)
+        $(info ***********************************************************************)
+        $(info ***********************************************************************)
+        $(error .)
+      else
+        $(info **  date.  For the most functional and stable features you shoud     **)
+        $(info **  Download the file:                                               **)
+        $(info **  https://github.com/simh/windows-build/archive/windows-build.zip  **)
+        $(info **  Extract the windows-build-windows-build folder it contains to    **)
+        $(info **  $(abspath ..\)                                                   **)
+        $(info ***********************************************************************)
+        $(info ***********************************************************************)
+        $(info .)
+        $(error Update windows-build)
+      endif
+    endif
+    ifeq (pcre,$(shell if exist ..\windows-build\PCRE\include\pcre.h echo pcre))
+      OS_CCDEFS += -DHAVE_PCRE_H -DPCRE_STATIC -I$(abspath ../windows-build/PCRE/include)
+      OS_LDFLAGS += -lpcre -L../windows-build/PCRE/lib/
+      $(info using libpcre: $(abspath ../windows-build/PCRE/lib/pcre.a) $(abspath ../windows-build/PCRE/include/pcre.h))
+    endif
+    ifeq (slirp,slirp)
+      NETWORK_OPT += -Islirp -Islirp_glue -Islirp_glue/qemu -DHAVE_SLIRP_NETWORK -DUSE_SIMH_SLIRP_DEBUG slirp/*.c slirp_glue/*.c -lIphlpapi
+      NETWORK_LAN_FEATURES += NAT(SLiRP)
+    endif
+  endif
+  ifneq (,$(call find_include,ddk/ntdddisk))
+    CFLAGS_I = -DHAVE_NTDDDISK_H
+  endif
+endif # Win32 (via MinGW)
+ifneq (,$(GIT_COMMIT_ID))
+  CFLAGS_GIT = -DSIM_GIT_COMMIT_ID=$(GIT_COMMIT_ID)
+endif
+ifneq (,$(GIT_COMMIT_TIME))
+  CFLAGS_GIT += -DSIM_GIT_COMMIT_TIME=$(GIT_COMMIT_TIME)
+endif
+ifneq (,$(UNSUPPORTED_BUILD))
+  CFLAGS_GIT += -DSIM_BUILD=Unsupported=$(UNSUPPORTED_BUILD)
 endif
 ifneq ($(DEBUG),)
   CFLAGS_G = -g -ggdb -g3
   CFLAGS_O = -O0
   BUILD_FEATURES = - debugging support
 else
-  CFLAGS_O = -O2
-  LDFLAGS_O = 
-  ifeq (Darwin,$(OSTYPE))
+  ifneq (,$(findstring clang,$(COMPILER_NAME))$(findstring LLVM,$(COMPILER_NAME)))
+    CFLAGS_O = -O2 -fno-strict-overflow
+    GCC_OPTIMIZERS_CMD = ${GCC} --help
     NO_LTO = 1
+  else
+    NO_LTO = 1
+    ifeq (Darwin,$(OSTYPE))
+      CFLAGS_O += -O4 -flto -fwhole-program
+    else
+      CFLAGS_O := -O2
+    endif
   endif
+  LDFLAGS_O = 
   GCC_MAJOR_VERSION = $(firstword $(subst  ., ,$(GCC_VERSION)))
   ifneq (3,$(GCC_MAJOR_VERSION))
     ifeq (,$(GCC_OPTIMIZERS_CMD))
-      GCC_OPTIMIZERS_CMD = $(GCC) --help=optimizers
+      GCC_OPTIMIZERS_CMD = ${GCC} --help=optimizers
+      GCC_COMMON_CMD = ${GCC} --help=common
     endif
+  endif
+  ifneq (,$(GCC_OPTIMIZERS_CMD))
     GCC_OPTIMIZERS = $(shell $(GCC_OPTIMIZERS_CMD))
   endif
+  ifneq (,$(GCC_COMMON_CMD))
+    GCC_OPTIMIZERS += $(shell $(GCC_COMMON_CMD))
+  endif
   ifneq (,$(findstring $(GCC_VERSION),$(LTO_EXCLUDE_VERSIONS)))
     NO_LTO = 1
   endif
@@ -540,13 +1245,10 @@ else
 endif
 ifneq (3,$(GCC_MAJOR_VERSION))
   ifeq (,$(GCC_WARNINGS_CMD))
-    GCC_WARNINGS_CMD = $(GCC) --help=warnings
-  endif
-  ifneq (,$(findstring -Wunused-result,$(shell $(GCC_WARNINGS_CMD))))
-    CFLAGS_O += -Wno-unused-result
+    GCC_WARNINGS_CMD = ${GCC} --help=warnings
   endif
 endif
-ifneq (clean,$(MAKECMDGOALS))
+ifneq (clean,${MAKECMDGOALS})
   BUILD_FEATURES := $(BUILD_FEATURES). $(COMPILER_NAME)
   $(info ***)
   $(info *** $(BUILD_SINGLE)Simulator$(BUILD_MULTIPLE) being built with:)
@@ -554,16 +1256,34 @@ ifneq (clean,$(MAKECMDGOALS))
   ifneq (,$(NETWORK_FEATURES))
     $(info *** $(NETWORK_FEATURES).)
   endif
+  ifneq (,$(NETWORK_LAN_FEATURES))
+    $(info *** - Local LAN packet transports: $(NETWORK_LAN_FEATURES))
+  endif
+  ifneq (,$(VIDEO_FEATURES))
+    $(info *** $(VIDEO_FEATURES).)
+  endif
+  ifneq (,$(TESTING_FEATURES))
+    $(info *** $(TESTING_FEATURES).)
+  endif
+  ifneq (,$(GIT_COMMIT_ID))
+    $(info ***)
+    $(info *** git commit id is $(GIT_COMMIT_ID).)
+    $(info *** git commit time is $(GIT_COMMIT_TIME).)
+  endif
   $(info ***)
 endif
+ifneq ($(DONT_USE_ROMS),)
+  ROMS_OPT = -DDONT_USE_INTERNAL_ROM
+else
+  BUILD_ROMS = ${BIN}buildtools/BuildROMs${EXE}
+endif
 ifneq ($(DONT_USE_READER_THREAD),)
   NETWORK_OPT += -DDONT_USE_READER_THREAD
 endif
 
-CC_STD = -std=c99
 CC_OUTSPEC = -o $@
-CC = $(GCC) $(CC_STD) -U__STRICT_ANSI__ $(CFLAGS_G) $(CFLAGS_O) -I . $(OS_CCDEFS) $(ROMS_OPT)
-LDFLAGS = $(OS_LDFLAGS) $(NETWORK_LDFLAGS) $(LDFLAGS_O)
+CC := ${GCC} ${CC_STD} -U__STRICT_ANSI__ ${CFLAGS_G} ${CFLAGS_O} ${CFLAGS_GIT} ${CFLAGS_I} -DSIM_COMPILER="${COMPILER_NAME}" -DSIM_BUILD_TOOL=simh-makefile -I . ${OS_CCDEFS} ${ROMS_OPT}
+LDFLAGS := ${OS_LDFLAGS} ${NETWORK_LDFLAGS} ${LDFLAGS_O}
 
 #
 # Common Libraries
diff --git a/scp.c b/scp.c
index 0eb3d0f8..6bfbdc01 100644
--- a/scp.c
+++ b/scp.c
@@ -1,6 +1,6 @@
 /* scp.c: simulator control program
 
-   Copyright (c) 1993-2020, Robert M Supnik
+   Copyright (c) 1993-2022, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -23,7 +23,17 @@
    used in advertising or otherwise to promote the sale, use or other dealings
    in this Software without prior written authorization from Robert M Supnik.
 
+   06-Mar-22    RMS     Removed UNIT_RAW support
    21-Oct-21    RMS     Fixed bug in byte deposits if aincr > 1
+   20=Sep-21    RMS     Fixed bug in nested DO recognition (per Mark Pizzolato)
+   15-Apr-21    RMS     Changed RUN to store new PC value both before RESET
+                        (former behavior) and after (per Mark Pizzolato)
+   18-Mar-21    JDB     Revised "attach_unit" and "detach_unit" for pipe support
+                        Modified tests to allow UNIT_RO without UNIT_ROABLE
+   16-Feb-21    JDB     Rewrote get_rval, put_rval to support arrays of structures
+   01-Feb-21    JDB     Added casts for down-conversions
+   25-Jan-21    JDB     REG "size" field now determines access size
+                        REG "maxval" field now determines maximum allowed value
    30-Nov-20    RMS     Fixed RUN problem if CPU reset clears PC (Mark Pizzolato)
    09-Nov-20    RMS     Added hack for sim_card multiple attach (Mark Pizzolato)
    23-Oct-20    JDB     Added tmxr_post_logs calls to flush and close log files
@@ -230,8 +240,9 @@
 #include "sim_tmxr.h"
 #include <signal.h>
 #include <ctype.h>
+#include <sys/stat.h>
 
-#if defined(HAVE_DLOPEN)                                 /* Dynamic Readline support */
+#if defined(SIM_HAVE_DLOPEN)                             /* Dynamic Readline support */
 #include <dlfcn.h>
 #endif
 
@@ -258,8 +269,6 @@
     x = sim_interval
 
 #define SZ_D(dp) (size_map[((dp)->dwidth + CHAR_BIT - 1) / CHAR_BIT])
-#define SZ_R(rp) \
-    (size_map[((rp)->width + (rp)->offset + CHAR_BIT - 1) / CHAR_BIT])
 #if defined (USE_INT64)
 #define SZ_LOAD(sz,v,mb,j) \
     if (sz == sizeof (uint8)) v = *(((uint8 *) mb) + ((uint32) j)); \
@@ -374,7 +383,8 @@ t_stat ex_reg (FILE *ofile, t_value val, int32 flag, REG *rptr, uint32 idx);
 t_stat dep_reg (int32 flag, char *cptr, REG *rptr, uint32 idx);
 t_stat exdep_addr_loop (FILE *ofile, SCHTAB *schptr, int32 flag, char *cptr,
     t_addr low, t_addr high, DEVICE *dptr, UNIT *uptr);
-t_stat ex_addr (FILE *ofile, int32 flag, t_addr addr, DEVICE *dptr, UNIT *uptr, int32 dfltinc);
+t_stat ex_addr (FILE *ofile, int32 flag, t_addr addr, DEVICE *dptr,
+    UNIT *uptr, int32 dfltinc);
 t_stat dep_addr (int32 flag, char *cptr, t_addr addr, DEVICE *dptr,
     UNIT *uptr, int32 dfltinc);
 t_stat step_svc (UNIT *ptr);
@@ -1020,7 +1030,7 @@ do {
     sim_switches = 0;                                   /* init switches */
     isdo = FALSE;
     if (cmdp = find_cmd (gbuf)) {                       /* lookup command */
-        isdo = (MATCH_CMD (gbuf, "DO") == 0);
+        isdo = (strcmp (cmdp->name, "DO") == 0);
         if (isdo) {                                     /* DO command? */
             if (flag >= DO_NEST_LVL)                    /* nest too deep? */
                 stat = SCPE_NEST;
@@ -1374,8 +1384,9 @@ if (cptr)
 if (uptr == NULL)
     return SCPE_NOFNC;
 if (((uptr->flags & UNIT_SEQ) == 0) ||                  /* must be sequential, */
-    ((uptr->flags & UNIT_ROABLE) != 0) ||               /* not RO settable */
-    ((uptr->flags & UNIT_MUSTBUF) != 0))                /* not buffered */
+    ((uptr->flags & (UNIT_RO | UNIT_ROABLE)) != 0) ||   /* not RO settable */
+    ((uptr->flags & UNIT_MUSTBUF) != 0) ||              /* not buffered */
+    ((uptr->dynflags & UNIT_PIPE) != 0))                /* not a pipe */
     return SCPE_NOFNC;
 if ((uptr->flags & UNIT_ATT) == 0)                      /* must be attached */
     return SCPE_UNATT;
@@ -2127,9 +2138,21 @@ return attach_unit (uptr, cptr);                        /* no, std routine */
 
 /* Attach unit to file */
 
+#if !defined (S_ISFIFO)
+  #if !defined (S_IFMT) && defined (_S_IFMT)
+  #define S_IFMT   _S_IFMT
+  #endif
+  #if defined (_S_IFIFO)
+  #define S_ISFIFO(m)   (((m) & S_IFMT) == _S_IFIFO)
+  #else
+  #define S_ISFIFO(m)   0
+  #endif
+#endif
+
 t_stat attach_unit (UNIT *uptr, char *cptr)
 {
 DEVICE *dptr;
+struct stat info;
 
 if (!(uptr->flags & UNIT_ATTABLE))                      /* not attachable? */
     return SCPE_NOATT;
@@ -2141,8 +2164,24 @@ uptr->filename = (char *) calloc (CBUFSIZE, sizeof (char)); /* alloc name buf */
 if (uptr->filename == NULL)
     return SCPE_MEM;
 strncpy (uptr->filename, cptr, CBUFSIZE);               /* save name */
-if (sim_switches & SWMASK ('R')) {                      /* read only? */
-    if ((uptr->flags & UNIT_ROABLE) == 0)               /* allowed? */
+
+if ((!stat (cptr, &info)) && S_ISFIFO (info.st_mode))   /* if file exists and is a pipe */
+    if (uptr->flags & UNIT_SEQ) {                       /*   then if the unit is sequential */
+        if (uptr->flags & (UNIT_RO | UNIT_ROABLE))      /* if the unit is readable */
+            uptr->fileref = sim_fopen (cptr, "rb");     /*   then open the pipe for reading */
+        else                                            /* otherwise */
+            uptr->fileref = sim_fopen (cptr, "wb");     /*   open the pipe for writing */
+
+        if (uptr->fileref == NULL)                          /* if the file failed to open */
+            return attach_err (uptr, SCPE_OPENERR);         /*   then report the error */
+        else                                                /* otherwise */
+            uptr->dynflags = uptr->dynflags | UNIT_PIPE;    /*   set the pipe flag */
+        }
+    else                                                /* otherwise the unit is not sequential */
+        return SCPE_NOFNC;                              /*   so it cannot be attached to a pipe */
+
+else if (sim_switches & SWMASK ('R')) {                 /* read only? */
+    if ((uptr->flags & (UNIT_RO | UNIT_ROABLE)) == 0)   /* allowed? */
         return attach_err (uptr, SCPE_NORO);            /* no, error */
     uptr->fileref = sim_fopen (cptr, "rb");             /* open rd only */
     if (uptr->fileref == NULL)                          /* open fail? */
@@ -2152,18 +2191,18 @@ if (sim_switches & SWMASK ('R')) {                      /* read only? */
         sim_printf ("%s: unit is read only\n", sim_dname (dptr));
     }
 else if (sim_switches & SWMASK ('N')) {                 /* new file only? */
-        uptr->fileref = sim_fopen (cptr, "wb+");        /* open new file */
-        if (uptr->fileref == NULL)                      /* open fail? */
-            return attach_err (uptr, SCPE_OPENERR);     /* yes, error */
-        if (!sim_quiet)
-            sim_printf ("%s: creating new file\n", sim_dname (dptr));
+    uptr->fileref = sim_fopen (cptr, "wb+");            /* open new file */
+    if (uptr->fileref == NULL)                          /* open fail? */
+        return attach_err (uptr, SCPE_OPENERR);         /* yes, error */
+    if (!sim_quiet)
+        sim_printf ("%s: creating new file\n", sim_dname (dptr));
     }
 else {                                                  /* normal */
     uptr->fileref = sim_fopen (cptr, "rb+");            /* open r/w */
     if (uptr->fileref == NULL) {                        /* open fail? */
         if ((errno == EROFS) || (errno == EACCES)) {    /* read only? */
-            if ((uptr->flags & UNIT_ROABLE) == 0)       /* allowed? */
-                return attach_err (uptr, SCPE_NORO);    /* no error */
+            if ((uptr->flags & (UNIT_RO | UNIT_ROABLE)) == 0)   /* allowed? */
+                return attach_err (uptr, SCPE_NORO);            /* no error */
             uptr->fileref = sim_fopen (cptr, "rb");     /* open rd only */
             if (uptr->fileref == NULL)                  /* open fail? */
                 return attach_err (uptr, SCPE_OPENERR); /* yes, error */
@@ -2316,6 +2355,7 @@ if ((uptr->flags & UNIT_BUF) && (uptr->filebuf)) {      /* buffered? */
     }
 uptr->flags = uptr->flags & ~(UNIT_ATT |                /* clear ATT */
     ((uptr->flags & UNIT_ROABLE) ? UNIT_RO : 0));       /* clear RO if dynamic */
+uptr->dynflags = uptr->dynflags & ~UNIT_PIPE;           /* clear the pipe flag */
 free (uptr->filename);
 uptr->filename = NULL;
 if (fclose (uptr->fileref) == EOF)
@@ -2560,7 +2600,7 @@ void *mbuf;
 int32 j, blkcnt, limit, unitno, time, flg;
 uint32 us, depth;
 t_addr k, high, old_capac;
-t_value val, mask;
+t_value val, max;
 t_stat r;
 size_t sz;
 t_bool v35, v32;
@@ -2732,10 +2772,13 @@ for ( ;; ) {                                            /* device loop */
         if (depth != rptr->depth)                       /* [V2.10+] mismatch? */
             sim_printf ("Register depth mismatch: %s %s, file = %d, sim = %d\n",
                 sim_dname (dptr), buf, depth, rptr->depth);
-        mask = width_mask[rptr->width];                 /* get mask */
+        if (rptr->maxval > 0)                           /* if a maximum value is defined */
+            max = rptr->maxval;                         /*   then use it */
+        else                                            /* otherwise */
+            max = width_mask[rptr->width];              /*   the mask defines the maximum value */
         for (us = 0; us < depth; us++) {                /* loop thru values */
             READ_I (val);                               /* read value */
-            if (val > mask)                             /* value ok? */
+            if (val > max)                              /* value ok? */
                 sim_printf ("Invalid register value: %s %s\n", sim_dname (dptr), buf);
             else if (us < rptr->depth)                  /* in range? */
                 put_rval (rptr, us, val);
@@ -2777,14 +2820,17 @@ if ((flag == RU_RUN) || (flag == RU_GO)) {              /* run or go */
             pcv = sim_vm_parse_addr (sim_dflt_dev, gbuf, &tptr);
         else pcv = strtotv (gbuf, &tptr, sim_PC->radix);/* parse PC */
         if ((tptr == gbuf) || (*tptr != 0) ||           /* error? */
-            (pcv > width_mask[sim_PC->width]))
+            (pcv > (sim_PC->maxval > 0
+                     ? sim_PC->maxval
+                     : width_mask[sim_PC->width])))
             return SCPE_ARG;
+        put_rval (sim_PC, 0, pcv);			/* store new PC */
         }
     if ((flag == RU_RUN) &&                             /* run? */
         ((r = run_boot_prep ()) != SCPE_OK))            /* reset sim */
         return r;
     if (new_pcv)                                        /* new PC value? */
-        put_rval (sim_PC, 0, pcv);
+        put_rval (sim_PC, 0, pcv);                      /* store again */
     }
 
 else if (flag == RU_STEP) {                             /* step */
@@ -2830,7 +2876,8 @@ else if (flag != RU_CONT)                               /* must be cont */
 for (i = 1; (dptr = sim_devices[i]) != NULL; i++) {     /* reposition all */
     for (j = 0; j < dptr->numunits; j++) {              /* seq devices */
         uptr = dptr->units + j;
-        if ((uptr->flags & (UNIT_ATT + UNIT_SEQ)) == (UNIT_ATT + UNIT_SEQ))
+        if ((uptr->flags & (UNIT_ATT + UNIT_SEQ)) == (UNIT_ATT + UNIT_SEQ) &&
+            (uptr->dynflags & UNIT_PIPE) == 0)
             sim_fseek (uptr->fileref, uptr->pos, SEEK_SET);
         }
     }
@@ -2875,7 +2922,6 @@ for (i = 1; (dptr = sim_devices[i]) != NULL; i++) {     /* flush attached files
         if ((uptr->flags & UNIT_ATT) &&                 /* attached, */
             !(uptr->flags & UNIT_BUF) &&                /* not buffered, */
             (uptr->fileref) &&                          /* real file, */
-            !(uptr->flags & UNIT_RAW) &&                /* not raw, */
             !(uptr->flags & UNIT_RO))                   /* not read only? */
             fflush (uptr->fileref);
         }
@@ -3155,11 +3201,15 @@ t_stat exdep_addr_loop (FILE *ofile, SCHTAB *schptr, int32 flag, char *cptr,
 t_addr i, mask;
 t_stat reason, dfltinc;
 
+
 if (uptr->flags & UNIT_DIS)                             /* disabled? */
     return SCPE_UDIS;
 mask = (t_addr) width_mask[dptr->awidth];
 if ((low > mask) || (high > mask) || (low > high))
     return SCPE_ARG;
+dfltinc =  parse_sym ("0", 0, uptr, sim_eval, sim_switches);
+if (dfltinc > 0)                                         /* parse_sym doing nums? */
+    dfltinc = 1 - dptr->aincr;                          /* no, use std dflt incr */
 for (i = low; i <= high; ) {                            /* all paths must incr!! */
     reason = get_aval (i, dptr, uptr);                  /* get data */
     if (reason != SCPE_OK)                              /* return if error */
@@ -3229,43 +3279,50 @@ return SCPE_OK;
         idx     =       index
    Outputs:
         return  =       register value
+
+   Implementation notes:
+
+    1. The stride is the size of the element spacing for arrays, which is
+       equivalent to the addressing increment for array subscripting.  For
+       scalar registers, the stride will be zero (as will the idx value), so the
+       access pointer is same as the specified location pointer.
+
+    2. The size of the t_value type is determined by the USE_INT64 symbol and
+       will be either a 32-bit or a 64-bit type.  It represents the largest
+       value that can be returned and so is the default if one of the smaller
+       sizes is not indicated.  If USE_INT64 is not defined, t_value will be
+       identical to uint32.  In this case, compilers are generally smart enough
+       to eliminate the 32-bit size test and combine the two assignments into a
+       single default assignment.
 */
 
 t_value get_rval (REG *rptr, uint32 idx)
 {
-size_t sz;
 t_value val;
-UNIT *uptr;
+void    *ptr;
 
-sz = SZ_R (rptr);
-if ((rptr->depth > 1) && (rptr->flags & REG_CIRC)) {
-    idx = idx + rptr->qptr;
-    if (idx >= rptr->depth) idx = idx - rptr->depth;
+if ((rptr->depth > 1) && (rptr->flags & REG_CIRC)) {    /* if the register is a circular queue */
+    idx = idx + rptr->qptr;                             /*   then adjust the index relative to the queue */
+    if (idx >= rptr->depth)                             /* if the index is beyond the end of the array */
+        idx = idx - rptr->depth;                        /*   then wrap it around */
     }
-if ((rptr->depth > 1) && (rptr->flags & REG_UNIT)) {
-    uptr = ((UNIT *) rptr->loc) + idx;
-#if defined (USE_INT64)
-    if (sz <= sizeof (uint32))
-        val = *((uint32 *) uptr);
-    else val = *((t_uint64 *) uptr);
-#else
-    val = *((uint32 *) uptr);
-#endif
-    }
-else if (((rptr->depth > 1) || (rptr->flags & REG_FIT)) &&
-    (sz == sizeof (uint8)))
-    val = *(((uint8 *) rptr->loc) + idx);
-else if (((rptr->depth > 1) || (rptr->flags & REG_FIT)) &&
-    (sz == sizeof (uint16)))
-    val = *(((uint16 *) rptr->loc) + idx);
-#if defined (USE_INT64)
-else if (sz <= sizeof (uint32))
-     val = *(((uint32 *) rptr->loc) + idx);
-else val = *(((t_uint64 *) rptr->loc) + idx);
-#else
-else val = *(((uint32 *) rptr->loc) + idx);
-#endif
-val = (val >> rptr->offset) & width_mask[rptr->width];
+
+ptr = ((char *) rptr->loc) + (idx * rptr->stride);      /* point at the starting byte of the item */
+
+if (rptr->size == sizeof (uint8))                       /* get the value */
+    val = *((uint8 *) ptr);                             /*   using a size */
+                                                        /*     appropriate to */
+else if (rptr->size == sizeof (uint16))                 /*       the size of */
+    val = *((uint16 *) ptr);                            /*         the underlying type */
+
+else if (rptr->size == sizeof (uint32))
+    val = *((uint32 *) ptr);
+
+else                                                    /* if the element size is non-standard */
+    val = *((t_value *) ptr);                           /*   then access using the largest size permitted */
+
+val = (val >> rptr->offset) & width_mask[rptr->width];  /* shift and mask to obtain the final value */
+
 return val;
 }
 
@@ -3283,7 +3340,7 @@ return val;
 t_stat dep_reg (int32 flag, char *cptr, REG *rptr, uint32 idx)
 {
 t_stat r;
-t_value val, mask;
+t_value val, max;
 int32 rdx;
 char *tptr, gbuf[CBUFSIZE];
 
@@ -3300,17 +3357,20 @@ if (flag & EX_I) {
     if (*cptr == 0)                                     /* success */
         return SCPE_OK;
     }
-mask = width_mask[rptr->width];
+if (rptr->maxval > 0)                                   /* if a maximum value is defined */
+    max = rptr->maxval;                                 /*   then use it */
+else                                                    /* otherwise */
+    max = width_mask[rptr->width];                      /*   the mask defines the maximum value */
 GET_RADIX (rdx, rptr->radix);
 if ((rptr->flags & REG_VMAD) && sim_vm_parse_addr) {    /* address form? */
     val = sim_vm_parse_addr (sim_dflt_dev, cptr, &tptr);
-    if ((tptr == cptr) || (*tptr != 0) || (val > mask))
+    if ((tptr == cptr) || (*tptr != 0) || (val > max))
         return SCPE_ARG;
     }
 else if (!(rptr->flags & REG_VMFLAGS) ||                /* dont use sym? */
     (parse_sym (cptr, (rptr->flags & REG_UFMASK) | rdx, NULL,
                 &val, sim_switches | SIM_SW_REG) > SCPE_OK)) {
-    val = get_uint (cptr, rdx, mask, &r);
+    val = get_uint (cptr, rdx, max, &r);
     if (r != SCPE_OK)
         return SCPE_ARG;
     }
@@ -3326,59 +3386,54 @@ return SCPE_OK;
         rptr    =       pointer to register descriptor
         idx     =       index
         val     =       new value
-        mask    =       mask
    Outputs:
         none
+
+
+   Implementation notes:
+
+    1. mask and val are of type t_value, so an explicit cast is not needed for
+       that type of assignment.
+
+    2. See the notes for the get_rval routine for additional information
+       regarding the stride calculation and the t_value default assignment,
 */
 
 void put_rval (REG *rptr, uint32 idx, t_value val)
 {
-size_t sz;
 t_value mask;
-UNIT *uptr;
+void    *ptr;
 
-#define PUT_RVAL(sz,rp,id,v,m) \
-    *(((sz *) rp->loc) + id) = \
-            (*(((sz *) rp->loc) + id) & \
-            ~((m) << (rp)->offset)) | ((v) << (rp)->offset)
+if (rptr == sim_PC)                                     /* if the PC is changing */
+    sim_brk_npc (0);                                    /*   then notify the breakpoint package */
 
-if (rptr == sim_PC)
-    sim_brk_npc (0);
-sz = SZ_R (rptr);
-mask = width_mask[rptr->width];
-if ((rptr->depth > 1) && (rptr->flags & REG_CIRC)) {
-    idx = idx + rptr->qptr;
-    if (idx >= rptr->depth)
-        idx = idx - rptr->depth;
+mask = ~(width_mask [rptr->width] << rptr->offset);     /* set up a mask to produce a hole in the element */
+val  = val << rptr->offset;                             /*   and position the new value to fit the hole */
+
+if ((rptr->depth > 1) && (rptr->flags & REG_CIRC)) {    /* if the register is a circular queue */
+    idx = idx + rptr->qptr;                             /*   then adjust the index relative to the queue */
+    if (idx >= rptr->depth)                             /* if the index is beyond the end of the array */
+        idx = idx - rptr->depth;                        /*   then wrap it around */
     }
-if ((rptr->depth > 1) && (rptr->flags & REG_UNIT)) {
-    uptr = ((UNIT *) rptr->loc) + idx;
-#if defined (USE_INT64)
-    if (sz <= sizeof (uint32))
-        *((uint32 *) uptr) = (*((uint32 *) uptr) &
-        ~(((uint32) mask) << rptr->offset)) |
-        (((uint32) val) << rptr->offset);
-    else *((t_uint64 *) uptr) = (*((t_uint64 *) uptr)
-        & ~(mask << rptr->offset)) | (val << rptr->offset);
-#else
-    *((uint32 *) uptr) = (*((uint32 *) uptr) &
-        ~(((uint32) mask) << rptr->offset)) |
-        (((uint32) val) << rptr->offset);
-#endif
-    }
-else if (((rptr->depth > 1) || (rptr->flags & REG_FIT)) &&
-    (sz == sizeof (uint8)))
-    PUT_RVAL (uint8, rptr, idx, (uint32) val, (uint32) mask);
-else if (((rptr->depth > 1) || (rptr->flags & REG_FIT)) &&
-    (sz == sizeof (uint16)))
-    PUT_RVAL (uint16, rptr, idx, (uint32) val, (uint32) mask);
-#if defined (USE_INT64)
-else if (sz <= sizeof (uint32))
-    PUT_RVAL (uint32, rptr, idx, (int32) val, (uint32) mask);
-else PUT_RVAL (t_uint64, rptr, idx, val, mask);
-#else
-else PUT_RVAL (uint32, rptr, idx, val, mask);
-#endif
+
+ptr = ((char *) rptr->loc) + (idx * rptr->stride);      /* point at the starting byte of the item */
+
+if (rptr->size == sizeof (uint8))                       /* store the value */
+    *((uint8 *) ptr) =                                  /*   using a size */
+      (uint8) (*((uint8 *) ptr) & mask | val);          /*     appropriate to */
+                                                        /*       the size of */
+else if (rptr->size == sizeof (uint16))                 /*         the underlying type */
+    *((uint16 *) ptr) =
+      (uint16) (*((uint16 *) ptr) & mask | val);
+
+else if (rptr->size == sizeof (uint32))
+    *((uint32 *) ptr) =
+      (uint32) (*((uint32 *) ptr) & mask | val);
+
+else                                                    /* if the element size is non-standard */
+    *((t_value *) ptr) =                                /*   then access using the largest size permitted */
+      *((t_value *) ptr) & mask | val;
+
 return;
 }
 
@@ -3411,7 +3466,7 @@ if (!(flag & EX_E))
 GET_RADIX (rdx, dptr->dradix);
 if ((reason = fprint_sym (ofile, addr, sim_eval, uptr, sim_switches)) > 0) {
     fprint_val (ofile, sim_eval[0], rdx, dptr->dwidth, PV_RZRO);
-    return dfltinc;
+    reason = dfltinc;
     }
 if (flag & EX_I)
     fprintf (ofile, "\t");
@@ -3452,8 +3507,8 @@ for (i = 0, j = addr; i < sim_emax; i++, j = j + dptr->aincr) {
     else {
         if (!(uptr->flags & UNIT_ATT))
             return SCPE_UNATT;
-        if (((uptr->flags & UNIT_RAW) != 0) ||
-            (uptr->fileref == NULL))
+        if ((uptr->fileref == NULL) ||
+            ((uptr->dynflags & UNIT_PIPE) != 0))
             return SCPE_NOFNC;
         if (((uptr->flags & UNIT_FIX) != 0) &&
             (j >= uptr->capac)) {
@@ -3545,7 +3600,7 @@ for (i = 0, j = addr; i < count; i++, j = j + dptr->aincr) {
     else {
         if (!(uptr->flags & UNIT_ATT))
             return SCPE_UNATT;
-        if (uptr->flags & UNIT_RAW)
+        if (uptr->dynflags & UNIT_PIPE)
             return SCPE_NOFNC;
         if ((uptr->flags & UNIT_FIX) && (j >= uptr->capac))
             return SCPE_NXM;
@@ -3641,7 +3696,7 @@ return read_line_p (NULL, cptr, size, stream);
 char *read_line_p (char *prompt, char *cptr, int32 size, FILE *stream)
 {
 char *tptr;
-#if defined(HAVE_DLOPEN)
+#if defined(SIM_HAVE_DLOPEN)
 static int initialized = 0;
 static char *(*p_readline)(const char *) = NULL;
 static void (*p_add_history)(const char *) = NULL;
@@ -3705,7 +3760,7 @@ while (isspace (*cptr))                                 /* trim leading spc */
 if (*cptr == ';')                                       /* ignore comment */
     *cptr = 0;
 
-#if defined (HAVE_DLOPEN)
+#if defined (SIM_HAVE_DLOPEN)
 if (prompt && p_add_history && *cptr)                   /* Save non blank lines in history */
     p_add_history (cptr);
 #endif
@@ -3730,7 +3785,7 @@ char *get_glyph_gen (char *iptr, char *optr, char mchar, t_bool uc)
 {
 while ((isspace (*iptr) == 0) && (*iptr != 0) && (*iptr != mchar)) {
     if (islower (*iptr) && uc)
-        *optr = toupper (*iptr);
+        *optr = (char) toupper (*iptr);
     else *optr = *iptr;
     iptr++; optr++;
     }
@@ -4528,7 +4583,7 @@ do {
     d = d - 1;
     digit = (int32) (val % radix);
     val = val / radix;
-    dbuf[d] = (digit <= 9)? '0' + digit: 'A' + (digit - 10);
+    dbuf[d] = (char) ((digit <= 9)? '0' + digit: 'A' + (digit - 10));
     } while ((d > 0) && (val != 0));
 
 if (format != PV_LEFT) {
diff --git a/sim_defs.h b/sim_defs.h
index 440520e6..2d5d278a 100644
--- a/sim_defs.h
+++ b/sim_defs.h
@@ -1,6 +1,6 @@
 /* sim_defs.h: simulator definitions
 
-   Copyright (c) 1993-2020, Robert M Supnik
+   Copyright (c) 1993-2022, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -23,6 +23,13 @@
    used in advertising or otherwise to promote the sale, use or other dealings
    in this Software without prior written authorization from Robert M Supnik.
 
+   10-Mar-22    JDB     Modified REG macros to fix "stringizing" problem
+   12-Nov-21    JDB     Added UNIT_EXTEND dynamic flag
+   17-Mar-21    JDB     Added UNIT_PIPE dynamic flag
+   16-Feb-21    JDB     Added "stride" to REG to support arrays of structures
+                        Modified REG macros to initialize strides
+   21-Jan-21    JDB     Added "size" and "maxval" fields to the REG structure
+                        Modified REG macros to initialize access sizes
    09-Nov-20    RMS     More V4.X compatibility hooks (Mark Pizzolato)
    26-Oct-19    RMS     Removed MTAB_VAL definition
    23-Jun-17    RMS     Added #include sim_rev.h (Mark Pizzolato)
@@ -137,7 +144,7 @@ typedef signed short    int16;
 typedef signed int      int32;
 typedef unsigned char   uint8;
 typedef unsigned short  uint16;
-typedef unsigned int    uint32;         
+typedef unsigned int    uint32;
 typedef int             t_stat;                         /* status */
 typedef int             t_bool;                         /* boolean */
 
@@ -417,11 +424,13 @@ struct sim_unit {
 #define UNIT_UFMASK     (((1u << UNIT_V_RSV) - 1) & ~((1u << UNIT_V_UF) - 1))
 #define UNIT_RFLAGS     (UNIT_UFMASK|UNIT_DIS)          /* restored flags */
 
-/* Unit dynamic flags (dynflags) (from 4.0) 
+/* Unit dynamic flags (dynflags) (from 4.0)
    These flags are only set dynamically */
 
 #define UNIT_ATTMULT    000001                          /* allow multiple ATT cmd */
-#define UNIT_V_DF_TAPE  3                               /* tape density reservation */
+#define UNIT_PIPE       000002                          /* file is a pipe */
+#define UNIT_EXTEND     000004                          /* extended SIMH tape format is enabled */
+#define UNIT_V_DF_TAPE  3                               /* tape density reservation (bits 3-5) */
 #define UNIT_W_DF_TAPE  3
 
 /* Register data structure */
@@ -433,7 +442,10 @@ struct sim_reg {
     uint32              width;                          /* width */
     uint32              offset;                         /* starting bit */
     uint32              depth;                          /* save depth */
+    size_t              size;                           /* size of location in bytes */
+    size_t              stride;                         /* spacing of array elements in bytes */
     uint32              flags;                          /* flags */
+    t_value             maxval;                         /* maximum value */
     uint32              qptr;                           /* circ q ptr */
     };
 
@@ -443,11 +455,10 @@ struct sim_reg {
 #define REG_RO          00004                           /* read only */
 #define REG_HIDDEN      00010                           /* hidden */
 #define REG_NZ          00020                           /* must be non-zero */
-#define REG_UNIT        00040                           /* in unit struct */
 #define REG_CIRC        00100                           /* circular array */
 #define REG_VMIO        00200                           /* use VM data print/parse */
 #define REG_VMAD        00400                           /* use VM addr print/parse */
-#define REG_FIT         01000                           /* fit access to size */
+#define REG_FIT         00000                           /* fit access to size (obsolete) */
 #define REG_HRO         (REG_RO | REG_HIDDEN)           /* hidden, read only */
 
 #define REG_V_UF        16                              /* device specific */
@@ -520,7 +531,7 @@ struct sim_schtab {
 struct sim_brktab {
     t_addr              addr;                           /* address */
     int32               typ;                            /* mask of types */
-    int32               cnt;                            /* proceed count */     
+    int32               cnt;                            /* proceed count */
     char                *act;                           /* action string */
     };
 
@@ -540,31 +551,117 @@ struct sim_debtab {
 
 #define UDATA(act,fl,cap) NULL,act,NULL,NULL,NULL,0,0,(fl),0,(cap),0,0
 
-#if defined (__STDC__) || defined (_WIN32)
-#define ORDATA(nm,loc,wd) #nm, &(loc), 8, (wd), 0, 1
-#define DRDATA(nm,loc,wd) #nm, &(loc), 10, (wd), 0, 1
-#define HRDATA(nm,loc,wd) #nm, &(loc), 16, (wd), 0, 1
-#define FLDATA(nm,loc,pos) #nm, &(loc), 2, 1, (pos), 1
-#define GRDATA(nm,loc,rdx,wd,pos) #nm, &(loc), (rdx), (wd), (pos), 1
-#define BRDATA(nm,loc,rdx,wd,dep) #nm, (loc), (rdx), (wd), 0, (dep)
-#define VBRDATA(nm,loc,rdx,wd,dep) #nm, (loc), (rdx), (wd), 0, (dep)
-#define SAVEDATA(nm,loc) \
-    #nm, &(loc), 8, 8, 0, sizeof(loc), REG_HRO
+/* Register initialization macros.
+
+   The following macros should be used to initialize the elements of a
+   simulator's register array.  The macros provide simplified initialization,
+   ensure that unspecified fields are set appropriately, and insulate the
+   simulator writer from changes in the underlying REG structure.
+
+   The macros take varying numbers of parameters with the following meanings:
+
+     Param  Meaning
+     -----  ------------------------------------------
+      nm    Register symbolic name
+      loc   Location of the associated variable
+      aloc  Location of the associated array
+      floc  Location of the associated structure field
+      rdx   Display and entry radix
+      wd    Field width in bits
+      off   Field offset in bits from LSB
+      dep   Number of array elements
+      siz   Element size in bytes
+      str   Array element spacing in bytes
+
+   The macros have the following uses:
+
+     Macro     Use with
+     --------  ---------------------------------------------------------------
+     ORDATA    Scalar with octal display/entry
+     DRDATA    Scalar with decimal display/entry
+     HRDATA    Scalar with hexadecimal display/entry
+     FLDATA    Scalar with single bit display/entry
+     GRDATA    Scalar with with specification of radix/width/offset parameters
+
+     BRDATA    Singly-subscripted array
+     CRDATA    Doubly-subscripted array
+
+     SRDATA    Singly-subscripted array of general structure fields
+     URDATA    Singly-subscripted array of UNIT structure fields
+
+     XRDATA    Generic type with specification of all parameters
+     SAVEDATA  Generic type used only for persistence across SAVE/RESTORE
+
+   Normally, scalar and array locations specify the variable name; the names are
+   converted internally to pointers as needed.  However, the starting point of
+   a partial array may be specified by passing a pointer to the desired element.
+   For example:
+
+     BRDATA (SYM, array, ...)
+
+   ...specifies a register starting with array element zero, while:
+
+     BRDATA (SYM, &array[3], ...)
+
+   ...specifies a register starting with array element three.
+
+   For arrays of general structures, the names of the array and selected field
+   are given:
+
+     SRDATA (SYM, array, field, ...)
+
+   This specifies a arrayed register whose elements are array[0].field,
+   array[1].field, etc.
+
+
+   Implementation notes:
+
+    1. The "RegCheck" macro is used to ensure that each of the user macros has
+       the correct number of parameters.  This improves maintenance reliability,
+       as changes to the REG structure need to be reflected only in the
+       "RegCheck" macro.
+
+    2. "Stringization" must occur at the first macro call level to support
+       register names that are themselves macros.  Otherwise, macro expansion
+       will occur before stringization, resulting in the wrong register name.
+
+    3. Additional REG initialization values may be supplied after a macro
+       invocation.  If present, these begin with the "flags" field.
+
+    4. The URDATA macro is obsolescent and present for backward-compatibility.
+       It is a special case of the generic SRDATA macro, which provides the same
+       functionality.  Note also that URDATA requires a "flags" parameter value,
+       which is optional for all other macros.
+
+    5. The SAVEDATA macro is useful to indicate global variables whose values
+       must persist across a SAVE and RESTORE.  Such data is hidden from the
+       register user interface.
+*/
+
+#define RegCheck(nm,loc,rdx,wd,off,dep,siz,str) \
+          nm, (loc), (rdx), (wd), (off), (dep), (siz), (str)
+
+#define ORDATA(nm,loc,wd)           RegCheck (#nm, &(loc),  8, (wd), 0, 1, sizeof (loc), 0)
+#define DRDATA(nm,loc,wd)           RegCheck (#nm, &(loc), 10, (wd), 0, 1, sizeof (loc), 0)
+#define HRDATA(nm,loc,wd)           RegCheck (#nm, &(loc), 16, (wd), 0, 1, sizeof (loc), 0)
+#define FLDATA(nm,loc,off)          RegCheck (#nm, &(loc), 2, 1, (off), 1, sizeof (loc), 0)
+#define GRDATA(nm,loc,rdx,wd,off)   RegCheck (#nm, &(loc), (rdx), (wd), (off), 1, sizeof (loc), 0)
+
+#define BRDATA(nm,aloc,rdx,wd,dep)  RegCheck (#nm, (aloc), (rdx), (wd), 0, (dep), sizeof  *(aloc), sizeof  *(aloc))
+#define CRDATA(nm,aloc,rdx,wd,dep)  RegCheck (#nm, (aloc), (rdx), (wd), 0, (dep), sizeof **(aloc), sizeof **(aloc))
+
+#define SRDATA(nm,aloc,floc,rdx,wd,off,dep) \
+                                    RegCheck (#nm, &((aloc)->floc), (rdx), (wd), (off), (dep), \
+                                              sizeof ((aloc)->floc), sizeof (*(aloc)))
+
+#define XRDATA(nm,loc,rdx,wd,off,dep,siz,str) \
+                                    RegCheck (#nm, (loc), (rdx), (wd), (off), (dep), (siz), (str))
+
 #define URDATA(nm,loc,rdx,wd,off,dep,fl) \
-    #nm, &(loc), (rdx), (wd), (off), (dep), ((fl) | REG_UNIT)
-#else
-#define ORDATA(nm,loc,wd) "nm", &(loc), 8, (wd), 0, 1
-#define DRDATA(nm,loc,wd) "nm", &(loc), 10, (wd), 0, 1
-#define HRDATA(nm,loc,wd) "nm", &(loc), 16, (wd), 0, 1
-#define FLDATA(nm,loc,pos) "nm", &(loc), 2, 1, (pos), 1
-#define GRDATA(nm,loc,rdx,wd,pos) "nm", &(loc), (rdx), (wd), (pos), 1
-#define BRDATA(nm,loc,rdx,wd,dep) "nm", (loc), (rdx), (wd), 0, (dep)
-#define VBRDATA(nm,loc,rdx,wd,dep) "nm", (loc), (rdx), (wd), 0, (dep)
-#define SAVEDATA(nm,loc) \
-    "nm", &(loc), 8, 8, 0, sizeof(loc), REG_HRO
-#define URDATA(nm,loc,rdx,wd,off,dep,fl) \
-    "nm", &(loc), (rdx), (wd), (off), (dep), ((fl) | REG_UNIT)
-#endif
+                                    RegCheck (#nm, &(loc), (rdx), (wd), (off), (dep), \
+                                              sizeof (loc), sizeof (UNIT)), (fl)
+
+#define SAVEDATA(nm,loc)            RegCheck (#nm, &(loc), 8, 8, 0, sizeof (loc), 1, 1), REG_HRO
 
 /* Typedefs for principal structures */
 
@@ -587,7 +684,41 @@ typedef struct sim_debtab DEBTAB;
 #include "sim_fio.h"
 #include "sim_sock.h"
 
-/* V4 compatibility definitions
+/* V4 register definitions.
+
+
+   Implementation notes:
+
+    1. Unfortunately, the requirement that "stringization" must occur at the
+       first macro call level precludes defining these V4 macros in terms of
+       their V3 equivalents.  Hence, the V3 definitions must be repeated here.
+*/
+
+#define ORDATAD(nm,loc,wd,desc)                       RegCheck (#nm, &(loc),  8, (wd), 0, 1, sizeof (loc), 0)
+#define DRDATAD(nm,loc,wd,desc)                       RegCheck (#nm, &(loc), 10, (wd), 0, 1, sizeof (loc), 0)
+#define HRDATAD(nm,loc,wd,desc)                       RegCheck (#nm, &(loc), 16, (wd), 0, 1, sizeof (loc), 0)
+#define FLDATAD(nm,loc,off,desc)                      RegCheck (#nm, &(loc), 2, 1, (off), 1, sizeof (loc), 0)
+#define GRDATAD(nm,loc,rdx,wd,off,desc)               RegCheck (#nm, &(loc), (rdx), (wd), (off), 1, sizeof (loc), 0)
+#define BRDATAD(nm,loc,rdx,wd,dep,desc)               RegCheck (#nm, (loc), (rdx), (wd), 0, (dep), \
+                                                        sizeof  *(loc), sizeof  *(loc))
+#define URDATAD(nm,loc,rdx,wd,off,dep,fl,desc)        RegCheck (#nm, &(loc), (rdx), (wd), (off), (dep), \
+                                                        sizeof (loc), sizeof (UNIT)), (fl)
+
+#define ORDATADF(nm,loc,wd,desc,flds)                 RegCheck (#nm, &(loc),  8, (wd), 0, 1, sizeof (loc), 0)
+#define DRDATADF(nm,loc,wd,desc,flds)                 RegCheck (#nm, &(loc), 10, (wd), 0, 1, sizeof (loc), 0)
+#define HRDATADF(nm,loc,wd,desc,flds)                 RegCheck (#nm, &(loc), 16, (wd), 0, 1, sizeof (loc), 0)
+#define FLDATADF(nm,loc,off,desc,flds)                RegCheck (#nm, &(loc), 2, 1, (off), 1, sizeof (loc), 0)
+#define GRDATADF(nm,loc,rdx,wd,off,desc,flds)         RegCheck (#nm, &(loc), (rdx), (wd), (off), 1, sizeof (loc), 0)
+#define BRDATADF(nm,loc,rdx,wd,dep,desc,flds)         RegCheck (#nm, (loc), (rdx), (wd), 0, (dep), \
+                                                        sizeof  *(loc), sizeof  *(loc))
+#define URDATADF(nm,loc,rdx,wd,off,dep,fl,desc,flds)  RegCheck (#nm, &(loc), (rdx), (wd), (off), (dep), \
+                                                        sizeof (loc), sizeof (UNIT)), (fl)
+
+#ifndef INT64_C
+#define INT64_C(x)      (x##LL)
+#endif
+
+/* V4 compatibility definitions.
 
    The SCP API for version 4.0 introduces a number of "pointer-to-const"
    parameter qualifiers that were not present in the 3.x versions.  To maintain
@@ -596,46 +727,6 @@ typedef struct sim_debtab DEBTAB;
    when compiling for SIMH 3.x.
 */
 
-#if defined (__STDC__) || defined (_WIN32)
-#define ORDATAD(nm,loc,wd,desc) #nm, &(loc), 8, (wd), 0, 1
-#define DRDATAD(nm,loc,wd,desc) #nm, &(loc), 10, (wd), 0, 1
-#define HRDATAD(nm,loc,wd,desc) #nm, &(loc), 16, (wd), 0, 1
-#define FLDATAD(nm,loc,pos,desc) #nm, &(loc), 2, 1, (pos), 1
-#define GRDATAD(nm,loc,rdx,wd,pos,desc) #nm, &(loc), (rdx), (wd), (pos), 1
-#define BRDATAD(nm,loc,rdx,wd,dep,desc) #nm, (loc), (rdx), (wd), 0, (dep)
-#define URDATAD(nm,loc,rdx,wd,off,dep,fl,desc) \
-        #nm, &(loc), (rdx), (wd), (off), (dep), ((fl) | REG_UNIT)
-#define ORDATADF(nm,loc,wd,desc) #nm, &(loc), 8, (wd), 0, 1
-#define DRDATADF(nm,loc,wd,desc) #nm, &(loc), 10, (wd), 0, 1
-#define HRDATADF(nm,loc,wd,desc) #nm, &(loc), 16, (wd), 0, 1
-#define FLDATADF(nm,loc,pos,desc) #nm, &(loc), 2, 1, (pos), 1
-#define GRDATADF(nm,loc,rdx,wd,pos,desc) #nm, &(loc), (rdx), (wd), (pos), 1
-#define BRDATADF(nm,loc,rdx,wd,dep,desc) #nm, (loc), (rdx), (wd), 0, (dep)
-#define URDATADF(nm,loc,rdx,wd,off,dep,fl,desc) \
-        #nm, &(loc), (rdx), (wd), (off), (dep), ((fl) | REG_UNIT)
-#else
-#define ORDATAD(nm,loc,wd) "nm", &(loc), 8, (wd), 0, 1
-#define DRDATAD(nm,loc,wd) "nm", &(loc), 10, (wd), 0, 1
-#define HRDATAD(nm,loc,wd) "nm", &(loc), 16, (wd), 0, 1
-#define FLDATAD(nm,loc,pos) "nm", &(loc), 2, 1, (pos), 1
-#define GRDATAD(nm,loc,rdx,wd,pos) "nm", &(loc), (rdx), (wd), (pos), 1
-#define BRDATAD(nm,loc,rdx,wd,dep) "nm", (loc), (rdx), (wd), 0, (dep)
-#define URDATAD(nm,loc,rdx,wd,off,dep,fl) \
-    "nm", &(loc), (rdx), (wd), (off), (dep), ((fl) | REG_UNIT)
-#define ORDATADF(nm,loc,wd) "nm", &(loc), 8, (wd), 0, 1
-#define DRDATADF(nm,loc,wd) "nm", &(loc), 10, (wd), 0, 1
-#define HRDATADF(nm,loc,wd) "nm", &(loc), 16, (wd), 0, 1
-#define FLDATADF(nm,loc,pos) "nm", &(loc), 2, 1, (pos), 1
-#define GRDATADF(nm,loc,rdx,wd,pos) "nm", &(loc), (rdx), (wd), (pos), 1
-#define BRDATADF(nm,loc,rdx,wd,dep) "nm", (loc), (rdx), (wd), 0, (dep)
-#define URDATADF(nm,loc,rdx,wd,off,dep,fl) \
-    "nm", &(loc), (rdx), (wd), (off), (dep), ((fl) | REG_UNIT)
-#endif
-
-#ifndef INT64_C
-#define INT64_C(x)      (x##LL)
-#endif
-
 #ifdef PF_USER
 #undef PF_USER
 #endif /* PF_USER */
diff --git a/sim_rev.h b/sim_rev.h
index 2d065509..9f06f716 100644
--- a/sim_rev.h
+++ b/sim_rev.h
@@ -1,6 +1,6 @@
 /* sim_rev.h: simulator revisions and current rev level
 
-   Copyright (c) 1993-2020, Robert M Supnik
+   Copyright (c) 1993-2021, Robert M Supnik
 
    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
@@ -28,19 +28,60 @@
 #define _SIM_REV_H_     0
 
 #define SIM_MAJOR       3
-#define SIM_MINOR       11
+#define SIM_MINOR       12
 #define SIM_PATCH       2
 #define SIM_DELTA       0
 
-/* V3.11 revision history
+/* V3.12 revision history
 
-   V3.11 incorporates SCP additions and extensions by Dave Bryan to support his
-   HP simulators.
+   V3.12 incorporates a major rework of the register sizing macros and access
+   logic by Dave Bryan.
 
 patch   date            module(s) and fix(es)
 
-  2     tbd             scp.h
+  2     26-Mar-2022     sim_defs.h, scp.c
+                        - deprecated UNIT_RAW, UNIT_TEXT
+                        - dropped non-C_STD string support
+
+                        sim_tape.h, sim_tape.c
+                        - added extended tape format (Dave Bryan)
+
+                        all magtape simulators
+                        - added extra case points for new MTSE definitions
+
+                        pdp11_kg.c
+                        - fixed bug in repeated operations (Paul Koning)
+
+                        pdp11_rq.c
+                        - added additional disk types
+
+                        pdp8_fpp.c
+                        -   fix fencepost error in FP multiply extended precision (Rick Murphy)
+
+  1     01-Nov-2021     scp.c
+                        - fixed bugs in ID and search on PDP11, VAX, etc.
+
+                        sim_tape.c, sim_tape.h (Dave Bryan)
+                        - added sim_tape_erase routine
+                        - improved tape_erase_fwd corrupt image error checking
+
+                        pdp11_cpumod.c, pdp11_cpumod.h
+                        - added MMU as settable option to 11/23, 11/40, 11/45
+
+                        pdp8_cpu.c
+                        - fixed bug in reporting device conflicts (Hans-Bernd Eggenstein)
+
+                        pdp8_fpp.c
+                        - added DEVNO reporting
+
+                        pdp8_ttx.c
+                        - added DEVNO reporting from V4
+
+  0     15-Jun-2021     scp.h
                         - changed sim_vm_init to build time option (Dave Bryan)
+                        - changed register structure to separate access size from display size (Dave Bryan)
+                        - added maximum value to register structure (Dave Bryan)
+                        - added UNIT_PIPE dynamic flag (Dave Bryan)
 
                         scp.c
                         - changed sim_vm_init to build time option (Dave Bryan)
@@ -48,16 +89,31 @@ patch   date            module(s) and fix(es)
                         - flush terminal line logs at return from simulation (Dave Bryan)
                         - close terminal line logs at exit from simulator (Dave Bryan)
                         - fixed RUN problem if CPU reset clears PC (Mark Pizzolato)
+                        - separated register access size from display size (Dave Bryan)
+                        - added maximum value for register input (Dave Bryan)
+                        - added support for pipes as sequential IO sources (Dave Bryan)
 
                         sim_tmxr.h, sim_tmxr.c
                         - added capability to flush/close log files (Dave Bryan)
 
+                        i1401_defs.h, i1401_cpu.c
+                        - added maximum value for address registers
+
+                        i1620_defs.h, i1620_cpu.c
+                        - added maximum value for address registers
+
+                        i7094_mt.c
+                        - replaced dynamic buffer allocation with static (Mark Pizzolato)
+
                         nova_cpu.c
                         - fixed bug in history handling of C bit (Samuel Deutsch)
 
                         pdp10_tu.c
                         - fixed bad macro (Mark Pizzolato)
 
+                        pdp11_cpumod.h
+                        - added MMU as settable option to 11/23, 11/40, 11/45
+
                         pdp11_cpumod.c
                         - fixed KDJ11E programmable rate select (Paul Koning)
 
@@ -67,6 +123,19 @@ patch   date            module(s) and fix(es)
                         pdp18b_dr15.c
                         - zero out shared section on initial allocate (Dave Bryan)
 
+                        pdp18b_dt.c, pdp18b_rf.c
+                        - fixed bug if read overwrites WC memory location
+
+                        pdp8_clk.c
+                        - added diagnostic mode for timing dependency in TSS/8
+
+                        pdp8_df.c, pdp8_dt.c, pdpd8_rf.c
+                        - fixed bug if read overwrites WC memory location
+
+                        pdp8_sys.c
+                        - fixed treatment of RUBOUT in binary loader (Mark Pizzolato)
+                        - fixed decoding of RF/DF and LP intructions
+
                         s3_sys.c
                         - fixed bldaddr length (Mark Pizzolatto)
 
@@ -76,20 +145,30 @@ patch   date            module(s) and fix(es)
                         sds_cr.c, sds_cp.c
                         - New devices (Ken Rector)
 
+                        sds_cpu.c, sds_mt.c, sds_rad.c
+                        - Added C register support (Ken Rector)
+
                         sds_io.c
                         - TOP disconnects the channel rather than setting CHF_EOR
                         - Fixed overrun/underrun handling in single-word IO
 
                         sds_stddev.c
                         - TTO recognizes no leader flag (Ken Rector)
+                        - Added C register support to PTR boot (Ken Rector)
 
                         sds_sys.c
                         - Fixed handling of SDS character value 060 (Ken Rector)
-                        - Addec card reader and punch (Ken Rector)
+                        - Added card reader and punch (Ken Rector)
+                        - Added C register support to loader (Ken Rector)
 
                         vax_cpu.c
                         - added idle test for VMS 5.0/5.1 (Mark Pizzolato)
 
+/* V3.11 revision history
+
+   V3.11 incorporates SCP additions and extensions by Dave Bryan to support his
+   HP simulators.
+
   1     31-Mar-2020     scp.c and sim_tmxr_c
                         - new extensions to support HP simulators
                         - added SET <dev|unit> APPEND command