diff --git a/linc/CMakeLists.txt b/linc/CMakeLists.txt
deleted file mode 100644
index bce48ea8..00000000
--- a/linc/CMakeLists.txt
+++ /dev/null
@@ -1,32 +0,0 @@
-## LINC simulator
-##
-## This is an automagically generated file. Do NOT EDIT.
-## Any changes you make will be overwritten!!
-##
-## Make changes to the SIMH top-level makefile and then run the
-## "cmake/generate.py" script to regenerate these files.
-##
-##     cd cmake; python -m generate --help
-##
-## ------------------------------------------------------------
-
-if (HAVE_UNITY_FRAMEWORK AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/unit-tests/CMakeLists.txt")
-  add_subdirectory(unit-tests)
-endif ()
-
-add_simulator(linc
-    SOURCES
-        linc_cpu.c
-        linc_crt.c
-        linc_dpy.c
-        linc_kbd.c
-        linc_sys.c
-        linc_tape.c
-        linc_tty.c
-    INCLUDES
-        ${CMAKE_CURRENT_SOURCE_DIR}
-    FEATURE_DISPLAY
-    USES_AIO
-    LABEL linc
-    PKG_FAMILY default_family
-    TEST linc)
diff --git a/linc/README.md b/linc/README.md
new file mode 100644
index 00000000..57687814
--- /dev/null
+++ b/linc/README.md
@@ -0,0 +1,135 @@
+# LINC emulator
+
+This is an emulator for the classic LINC from 1965.
+
+### Devices
+
+- CPU - LINC processor.  If throttled to 125k, approximately original speed.
+- CRT - CRT display.  It can be disabled to run headless.
+- DPY - point-plotting display controller.
+- KBD - keyboard.  Input comes from typing in the CRT window.
+- SAM - sampled analog inputs.
+- TAPE - four tape drives.
+- TTY - teletype.
+
+### LOAD
+
+Software can be loaded into memory using the `LOAD` command.  It will
+normally read a file with 16-bit little endian words; the most
+significant four bits of each word should be zero.  If the `-O` switch
+is supplied, the input is a text file with octal numbers separated by
+whitespace.
+
+To start reading from some particular position in the input file, add
+`OFFSET=` after the file name and supply a number in octal.
+
+To specify where in the memory to put the data, add `START=` after the
+file name; the default is 0.  To specify how many words to load, use
+`LENGTH=`; the default is to write until the end of memory.
+
+A binary input file can be a tape image.  A plain image is 512 blocks
+of 256 words each, totalling 262144 bytes.  If the `-E` switch is
+used, there is a check for the extended image format that can have
+empty guard blocks at the beginning and the end.  The last three words
+in the extended format specify the block size, first forward block
+number, and first reverse block number.
+
+To state which tape block to start reading, add `BLOCK=` after the
+file name and supply an octal number in the range 0-777.
+
+### DO
+
+The SIMH `DO` command has been modified.  With arguments, it will
+execute a script file as normal.  Without argument, it acts like the
+DO button on the LINC control panel.  This executes one instruction
+from the left switches, with the right switches providing a second
+word if needed.
+
+### Tape drives
+
+To mount a tape image *file* on drive *n*, type `ATTACH TAPE<n>
+<file>`.  The plain or extended image format will be detected
+automatically.  Tape drives are numbered 0, 1, 4, and 5.
+
+The `BOOT TAPEn` command will act like entering a tape read command in
+the switches and starting the computer.  The default is to read eight
+blocks starting at 300, and start from location 20.  This is the
+conventional way to run LAP6.  You can also add `RDC=` or `RCG=` to
+boot some particular blocks.  `START=` can be used to specify the
+start address; it defaults to 20.
+
+### Keyboard
+
+The keys `0-9`, `A-Z`, and `Space` are mapped to their corresponding
+LINC keys.  `Enter` is mapped to `EOL`, `Delete` and `Backspace` are
+mapped to `DEL`, and `Shift` is mapped to `CASE`.  To type an upper
+case symbol on some key, press `CASE`, release it, and then type the
+key.  For convenience, `Alt` is mapped to `META`.
+
+The remaining keys are mapped thusly:
+- `F1` is mapped to the `pu` key.
+- `=` is mapped to the `i=` key.
+- `-` and `,` are mapped to the `-,` key.
+- `.` is mapped to the `+. key.
+- `\` is mapped to the `|⊟` key.
+- `[` and `left backslash` are mapped to the `*[` key.
+
+The remaining upper case symbols:
+- `CASE A` - `"`.
+- `CASE B` - `„`.
+- `CASE C` - `<`.
+- `CASE D` - `>`.
+- `CASE E` - `]`.
+- `CASE F` - `*`.
+- `CASE G` - `:`.
+- `CASE Space` - `?`.
+
+### Teletype
+
+The TTY device implmenents a teletype for printing output.  When a
+file is attached, it will receive text decoded at 110 baud from relay
+output 0.
+
+Some characters are translated by LAP6 from the LINC character to ASCII:
+- `i` to `&`
+- `p` to `'`
+- `|` to `\`
+- `u` to `%`
+- `⊟` to `$`
+- `_` to `@`
+- `"` to `^`
+- `„` to `;`
+
+### CPU
+
+Registers:
+- P - Instruction location, 10 bits.
+- C - Current instruction, 12 bits.
+- S - Memory address, 12 bits - 11 for address, 1 for halfword select.
+- B - Memory data buffer, 12 bits.
+- A - Accumulator, 12 bits - one's complement.
+- Z - Various, 12 bits.
+- L - Link, 1 bit.
+- OVF - Overflow, 1 bit.
+- IBZ - Tape interblock zone, 1 bit.
+- ENI - Interrupt enabled, 1 bit.
+- PINFF - Pause Interrupt enabled, 1 bit.
+
+Switches:
+- LSW - Left switches, 12 bits.
+- RSW - Right switches, 12 bits.
+- SSW - Sense switches, 6 bits.
+
+Inputs:
+- INTREQ, Interrupt request, 1 bit.
+- R - Relays, 6 bits.
+- XL - External levels, 12 of 1 bit each.
+- SAM - Sampled analog inputs, 16 of 8 bits each; one's complement.
+
+### Documentation
+
+Programming:
+https://bitsavers.org/pdf/washingtonUniversity/linc/Programming_the_LINC_Second_Edition_Jan69.pdf
+
+Using the LAP6 operating system, text editor, assembler, tape filing system:
+https://bitsavers.org/pdf/washingtonUniversity/linc/LINC_Reference_Manuals/LINC_Vol_16_Section_3_LAP6_Handbook_May67.pdf
diff --git a/linc/linc_cpu.c b/linc/linc_cpu.c
index 5dcf53fb..c8d174bc 100644
--- a/linc/linc_cpu.c
+++ b/linc/linc_cpu.c
@@ -28,19 +28,17 @@
 
 
 /* Debug */
-#define DBG_CPU         0001
+#define DBG_CPU   0001
+#define DBG_INT   0002
 
-#define WMASK  07777  /* Full word. */
-#define HMASK  04000  /* H bit; half word select. */
-#define AMASK  03777  /* Full memory address. */
-#define XMASK  01777  /* X part; low memory address. */
-#define DMASK  00777  /* Display coordinate. */
-#define LMASK  07700  /* Left half word. */
-#define RMASK  00077  /* Right half word; character. */
-#define IMASK  00020  /* Index bit. */
-#define BMASK  00017  /* Beta; index register. */
+#define INSN_ENI  00010
+#define INSN_NOP  00016
+#define INSN_OPR  00500
+#define INSN_MTP  00700
+#define INSN_JMP  06000
 
 #define X(_X)  ((_X) & XMASK)
+#define C03    (C & BMASK)
 
 /* CPU state. */
 static uint16 P;
@@ -57,9 +55,10 @@ static uint16 XL[12];
 static int paused;
 static int IBZ;
 static int OVF;
+static int INTREQ;
+static int ENI = 0;
 static int PINFF;
-static int interrupt;
-static int interrupt_enable = 0;
+static int DO = 0;
 
 static t_stat stop_reason;
 
@@ -80,6 +79,8 @@ static t_stat cpu_dep(t_value val, t_addr ea, UNIT *uptr, int32 sw);
 static t_stat cpu_reset(DEVICE *dptr);
 static t_stat cpu_set_hist(UNIT *uptr, int32 val, CONST char *cptr, void *desc);
 static t_stat cpu_show_hist(FILE *st, UNIT *uptr, int32 val, CONST void *desc);
+static t_stat linc_boot(int32 flag, CONST char *ptr);
+static t_stat linc_do(int32 flag, CONST char *ptr);
 
 static UNIT cpu_unit = { UDATA(NULL, UNIT_FIX + UNIT_BINK, MEMSIZE) };
 
@@ -90,16 +91,21 @@ REG cpu_reg[] = {
   { ORDATAD(L,   L,    1, "Link") },
   { ORDATAD(Z,   Z,   12, "?") },
   { ORDATAD(R,   R,    6, "Relay Register") },
-  { ORDATAD(S,   S,   12, "Memroy Address") },
+  { ORDATAD(S,   S,   12, "Memory Address") },
   { ORDATAD(B,   B,   12, "Memory Buffer") },
   { ORDATAD(LSW, LSW, 12, "Left Switches") },
   { ORDATAD(RSW, RSW, 12, "Right Switches") },
   { ORDATAD(SSW, SSW,  6, "Sense Switches") },
+
   { FLDATAD(paused, paused, 1, "Paused") },
-  { FLDATAD(IBZ, IBZ,  1, "Interblock zone") },
-  { FLDATAD(OVF, OVF,  1, "Overflow") },
-  { BRDATAD(SAM, SAM,  8, 8, 16, "Sampled analog inputs") },
-  { BRDATAD(XL,  XL,   8, 1, 12, "External levels") },
+  { FLDATAD(IBZ,    IBZ,    1, "Interblock zone") },
+  { FLDATAD(OVF,    OVF,    1, "Overflow") },
+  { FLDATAD(INTREQ, INTREQ, 1, "Interrupt") },
+  { FLDATAD(ENI,    ENI,    1, "Interrupt Enable") },
+  { FLDATAD(PIN,    PINFF,  1, "Pause Interrupt") },
+
+  { BRDATAD(SAM,    SAM,    8, 8, 16, "Sampled analog inputs") },
+  { BRDATAD(XL,     XL,     8, 1, 12, "External levels") },
   { NULL }
 };
 
@@ -111,6 +117,7 @@ static MTAB cpu_mod[] = {
 
 static DEBTAB cpu_deb[] = {
   { "CPU", DBG_CPU },
+  { "INTERRUPT", DBG_INT },
   { NULL, 0 }
 };
 
@@ -122,41 +129,86 @@ DEVICE cpu_dev = {
   NULL, NULL, NULL, NULL, NULL, NULL
 };
 
-static void pcinc(int flag)
+static CTAB linc_cmd[] = {
+  { "BOOT", &linc_boot, 0,
+    "BOOT {unit}                boot simulator\n"
+    "BOOT TAPE{n} RCG={blocks}  boot tape from specified blocks\n", NULL, &run_cmd_message },
+  { "DO", &linc_do, 0,
+    "DO {unit}                boot simulator\n"
+    "DO                       execute instruction in LSW and RSW\n", NULL, NULL },
+  { NULL }
+};
+
+static void cpu_ndxp(int flag)
 {
   if (flag)
     P = X(P + 1);
 }
 
-static void memaddr(uint16 addr)
+static void cpu_ndxc()
+{
+  C = (C & ~BMASK) | ((C + 1) & BMASK);
+}
+
+static void cpu_set_S(uint16 addr)
 {
   S = addr & WMASK;
 }
 
-static void membuf(uint16 data)
+static void cpu_set_B(uint16 data)
 {
   B = data & WMASK;
 }
 
-static void memrd(void)
+static void cpu_4ndxb()
 {
-  B = M[S & AMASK];
+  cpu_set_B(B + 4);
+}
+
+static void cpu_4ndxa()
+{
+  A = (A + 4) & WMASK;
+}
+
+static void cpu_mem_read(void)
+{
+  cpu_set_B(M[S & AMASK]);
   sim_interval--;
   if (sim_brk_summ && sim_brk_test(S & AMASK, SWMASK('R')))
     stop_reason = STOP_RBKPT;
 }
 
-static void memmd(void)
+static void cpu_mem_modify(void)
 {
   M[S & AMASK] = B;
   if (sim_brk_summ && sim_brk_test(S & AMASK, SWMASK('W')))
     stop_reason = STOP_WBKPT;
 }
 
-static void memwr(void)
+static void cpu_mem_write(void)
 {
   sim_interval--;
-  memmd();
+  cpu_mem_modify();
+}
+
+static void cpu_insn_addr()
+{
+  if (!DO) {
+    cpu_set_S(P);
+    cpu_ndxp(1);
+  }
+}
+
+static void cpu_insn_read()
+{
+  if (!DO)
+    cpu_mem_read();
+}
+
+static void cpu_fetch()
+{
+  cpu_insn_addr();
+  cpu_insn_read();
 }
 
 static int cpu_halfword(void)
@@ -181,30 +233,26 @@ static void cpu_index(void)
     } else {
       tmp = 1;
     }
-    membuf((B & 06000) | X(B + tmp));
-    memmd();
+    cpu_set_B((B & 06000) | X(B + tmp));
+    cpu_mem_modify();
   }
 }
 
 static void cpu_indexing(void)
 {
-  uint16 a = C & BMASK;
-  if (a == 0)
-    {
-      pcinc(1);
-      memaddr(P);
-      if ((C & IMASK) == 0) {
-        memrd();
-        memaddr(B);
-      }
-    }
-  else
-    {
-      memaddr(a);
-      memrd();
-      cpu_index();
-      memaddr(B);
+  uint16 a = C03;
+  if (a == 0) {
+    cpu_insn_addr();
+    if ((C & IMASK) == 0) {
+      cpu_insn_read();
+      cpu_set_S(B);
     }
+  } else {
+    cpu_set_S(a);
+    cpu_mem_read();
+    cpu_index();
+    cpu_set_S(B);
+  }
 }
 
 static void
@@ -214,15 +262,23 @@ cpu_misc(void)
   case 00000: //HLT
     stop_reason = STOP_HALT;
     break;
+  case 00002: //PDP
+    sim_debug(DBG_CPU, &cpu_dev, "This is not a PDP-12.\n");
+    break;
   case 00005: //ZTA
     A = Z >> 1;
     break;
   case 00010: //ENI
-    interrupt_enable = 1;
+    sim_debug(DBG_INT, &cpu_dev, "Interrupt enabled.\n");
+    ENI = 1;
     break;
   case 00011: //CLR
     A = L = Z = 0;
     break;
+  case 00012: //DIN
+    sim_debug(DBG_INT, &cpu_dev, "Interrupt disabled.\n");
+    ENI = 0;
+    break;
   case 00013: //Write gate on.
     break;
   case 00014: //ATR
@@ -241,33 +297,31 @@ cpu_misc(void)
 
 static void cpu_set(void)
 {
-  memaddr(P);
-  memrd();
-  pcinc(1);
+  cpu_fetch();
   if ((C & IMASK) == 0) {
-    memaddr(B);
-    memrd();
+    cpu_set_S(B);
+    cpu_mem_read();
   }
-  memaddr(C & BMASK);
-  memwr();
+  cpu_set_S(C03);
+  cpu_mem_write();
 }
 
 static void cpu_sam(void)
 {
-  // sample analog input C & BMASK
+  // sample analog input C03
   // 0-7 are pots, 10-17 are high speed inputs
   // i=0 wait 24 microseconds, i=1 do not wait
   if ((C & IMASK) == 0)
     sim_interval -= 3;
-  A = SAM[C & BMASK];
+  A = SAM[C03];
   if (A & 0200) /* One's complement +/-177. */
-    A |= 07600;
+    A |= 07400;
 }
 
 static void cpu_dis(void)
 {
-  memaddr(C & BMASK);
-  memrd();
+  cpu_set_S(C03);
+  cpu_mem_read();
   cpu_index();
   sim_debug(DBG_CPU, &cpu_dev, "DIS α=%02o B=%04o A=%04o\n", S, B, A);
   dpy_dis(B >> 11, B & DMASK, A & DMASK);
@@ -275,15 +329,16 @@ static void cpu_dis(void)
 
 static void cpu_xsk(void)
 {
-  memaddr(C & BMASK);
-  memrd();
+  cpu_set_S(C03);
+  cpu_mem_read();
   cpu_index();
-  pcinc(X(B) == 01777);
+  cpu_ndxp(X(B) == 01777);
 }
 
 static void cpu_rol(void)
 {
-  while (C & BMASK) {
+  C = (C & ~BMASK) | (~B & BMASK);
+  while (C03 != 017) {
     if (C & IMASK) {
       A = (A << 1) | L;
       L = A >> 12;
@@ -291,13 +346,14 @@ static void cpu_rol(void)
       A = (A << 1) | (A >> 11);
     }
     A &= WMASK;
-    C--;
+    cpu_ndxc();
   }
 }
 
 static void cpu_ror(void)
 {
-  while (C & BMASK) {
+  C = (C & ~BMASK) | (~B & BMASK);
+  while (C03 != 017) {
     Z = (Z >> 1) | ((A & 1) << 11);
     if (C & IMASK) {
       A |= L << 12;
@@ -307,28 +363,29 @@ static void cpu_ror(void)
       A = (A >> 1) | (A << 11);
       A &= WMASK;
     }
-    C--;
+    cpu_ndxc();
   }
 }
 
 static void cpu_scr(void)
 {
-  while (C & BMASK) {
+  C = (C & ~BMASK) | (~B & BMASK);
+  while (C03 != 017) {
     Z = (Z >> 1) | ((A & 1) << 11);
     if (C & IMASK)
       L = A & 1;
     A = (A & 04000) | (A >> 1);
-    C--;
+    cpu_ndxc();
   }
 }
 
 int cpu_skip(void)
 {
-  int flag = 0;
+  int flag;
   switch (C & 057) {
   case 000: case 001: case 002: case 003: case 004: case 005: case 006: case 007:
   case 010: case 011: case 012: case 013: //SXL
-    flag = XL[C & BMASK];
+    flag = XL[C03];
     break;
   case 015: //KST
     flag = kbd_struck();
@@ -338,6 +395,8 @@ int cpu_skip(void)
     break;
   case 046: //PIN
     flag = PINFF;
+    sim_debug(DBG_INT, &cpu_dev, "Pause interrupt enabled.\n");
+    PINFF = 0;
     break;
   case 050: //AZE
     flag = (A == 0) || (A == WMASK);
@@ -369,9 +428,9 @@ int cpu_skip(void)
 
 static void cpu_opr(void)
 {
-  switch (C & BMASK) {
+  switch (C03) {
   case 000: case 001: case 002: case 003: case 004: case 005: case 006: case 007:
-  case 010: case 011: case 012: case 013: case 014:
+  case 010: case 011: case 012: case 013:
     if (C & IMASK)
       ; //Pause.
     break;
@@ -389,37 +448,39 @@ static void cpu_opr(void)
 
 static void cpu_lmb(void)
 {
-  //Instruction field.
+  /* Lower memory bank. */
+  sim_debug(DBG_CPU, &cpu_dev, "This is not micro-LINC 300.\n");
 }
 
 static void cpu_umb(void)
 {
-  //Data field.
+  /* Upper memory bank. */
+  sim_debug(DBG_CPU, &cpu_dev, "This is not micro-LINC 300.\n");
 }
 
 static void cpu_tape(void)
 {
-  memaddr(P);
-  memrd();
-  pcinc(1);
+  cpu_fetch();
   tape_op();
 }
 
 static void cpu_lda(void)
 {
-  memrd();
+  cpu_mem_read();
   A = B;
 }
 
 static void cpu_sta(void)
 {
-  membuf(A);
-  memwr();
+  cpu_set_B(A);
+  /* Do not write immediate value if executing out of switches. */
+  if (!DO || (C & IMASK) == 0)
+    cpu_mem_write();
 }
 
 static void cpu_ada(void)
 {
-  memrd();
+  cpu_mem_read();
   OVF = ~(A ^ B);
   A += B;
   A += A >> 12;
@@ -430,13 +491,13 @@ static void cpu_ada(void)
 static void cpu_adm(void)
 {
   cpu_ada();
-  membuf(A);
-  memmd();
+  cpu_set_B(A);
+  cpu_mem_modify();
 }
 
 static void cpu_lam(void)
 {
-  memrd();
+  cpu_mem_read();
   A += L;
   L = A >> 12;
   A &= WMASK;
@@ -444,40 +505,43 @@ static void cpu_lam(void)
   if (A & 010000)
     L = 1;
   A &= WMASK;
-  membuf(A);
-  memmd();
-}
-
-static int32 sign_extend(uint16 x)
-{
-  if (x & 04000)
-    return -(x ^ WMASK);
-  else
-    return x;
+  cpu_set_B(A);
+  cpu_mem_modify();
 }
 
 static void cpu_mul(void)
 {
-  int32 product;
-  memrd();
-  // C used for counting.
-  product = sign_extend(A) * sign_extend(B);
-  if (product == 0 && ((A ^ B) & HMASK))
-    product = 037777777;
-  else if (product < 0)
-    product--;
+  uint32 factor, product;
+  cpu_mem_read();
+
+  C &= ~BMASK;
+  L = (A ^ B) >> 11;
+  if (A & HMASK)
+    A ^= WMASK;
+  if (B & HMASK)
+    B ^= WMASK;
+  Z = B;
+  cpu_set_B(A);
+  factor = B;
+  product = A = 0;
+  while (C03 < 12) {
+    if (Z & 1)
+      product += factor;
+    Z >>= 1;
+    factor <<= 1;
+    cpu_ndxc();
+  }
   if (S & HMASK)
-    A = (product >> 11) & WMASK;
-  else if ((A ^ B) & HMASK)
-    A = 04000 | (product & 03777);
+    A = product >> 11;
   else
     A = product & 03777;
-  L = A >> 11;
+  if (L)
+    A ^= 07777;
 }
 
 static void cpu_ldh(void)
 {
-  memrd();
+  cpu_mem_read();
   if ((S & HMASK) == 0)
     B >>= 6;
   A = B & RMASK;
@@ -485,91 +549,90 @@ static void cpu_ldh(void)
 
 static void cpu_sth(void)
 {
-  memrd();
+  cpu_mem_read();
   if (S & HMASK)
-    membuf((A & RMASK) | (B & LMASK));
+    cpu_set_B((A & RMASK) | (B & LMASK));
   else
-    membuf((A << 6) | (B & RMASK));
-  memmd();
+    cpu_set_B((A << 6) | (B & RMASK));
+  cpu_mem_modify();
 }
 
 static void cpu_shd(void)
 {
-  memrd();
+  cpu_mem_read();
   if ((S & HMASK) == 0)
     B >>= 6;
-  pcinc((A & RMASK) != (B & RMASK));
+  cpu_ndxp((A & RMASK) != (B & RMASK));
 }
 
 static void cpu_sae(void)
 {
-  memrd();
-  pcinc(A == B);
+  cpu_mem_read();
+  cpu_ndxp(A == B);
 }
 
 static void cpu_sro(void)
 {
-  memrd();
-  pcinc((B & 1) == 0);
-  membuf((B >> 1) | (B << 11));
-  memmd();
+  cpu_mem_read();
+  cpu_ndxp((B & 1) == 0);
+  cpu_set_B((B >> 1) | (B << 11));
+  cpu_mem_modify();
 }
 
 static void cpu_bcl(void)
 {
-  memrd();
+  cpu_mem_read();
   A &= ~B;
 }
 
 static void cpu_bse(void)
 {
-  memrd();
+  cpu_mem_read();
   A |= B;
 }
 
 static void cpu_bco(void)
 {
-  memrd();
+  cpu_mem_read();
   A ^= B;
 }
 
 static void cpu_dsc(void)
 {
-  int i, j;
-  uint16 data;
+  cpu_mem_read();
+  Z = B;
 
-  memrd();
-  data = B;
-
-  // C used for counting.
-  memaddr(1);
-  memrd();
+  cpu_set_S(1);
+  cpu_mem_read();
   sim_debug(DBG_CPU, &crt_dev, "DSC B=%04o A=%04o\n", B, A);
-  for (j = 0; j < 2; j++) {
-    membuf(B + 4);
-    A &= 07740;
-    for (i = 0; i < 6; i++) {
-      if (data & 1)
-        dpy_dis(B >> 11, B & DMASK, A & DMASK);
-      data >>= 1;
-      A += 4;
+
+  C &= ~BMASK;
+  while (C03 < 12) {
+    if (C03 == 0 || C03 == 6) {
+      A &= 07740;
+      cpu_4ndxb();
     }
+    if (Z & 1)
+      dpy_dis(B >> 11, B & DMASK, A & DMASK);
+    Z >>= 1;
+    cpu_4ndxa();
+    cpu_ndxc();
   }
-  memmd();
+  cpu_mem_write();
 }
 
 static void cpu_add(void)
 {
-  memaddr(X(C));
+  cpu_set_S(X(C));
   cpu_ada();
 }
 
 static void cpu_stc(void)
 {
-  memaddr(X(C));
-  membuf(A);
+  cpu_set_S(X(C));
+  cpu_set_B(A);
   A = 0;
-  memwr();
+  cpu_mem_write();
 }
 
 static void cpu_jmp(void)
@@ -577,9 +640,9 @@ static void cpu_jmp(void)
   uint16 tmp = P;
   P = X(C);
   if (P != 0) {
-    membuf(06000 | tmp);
-    memaddr(0);
-    memwr();
+    cpu_set_B(INSN_JMP | tmp);
+    cpu_set_S(0);
+    cpu_mem_write();
   }
 }
 
@@ -587,9 +650,9 @@ static void
 cpu_insn(void)
 {
   /* Cycle 0, or I. */
-  memaddr(P);
-  memrd();
-  C = B;
+  cpu_fetch();
+  if (!DO)
+    C = B;
 
   /* Cycle 1, or X. */
   if ((C & 07000) == 01000)
@@ -602,7 +665,6 @@ cpu_insn(void)
   }
 
   /* Cycle 2, or O. */
-  pcinc(1);
 
   /* Cycle 3, or E. */
   switch (C & 07740) {
@@ -632,7 +694,7 @@ cpu_insn(void)
     break;
   case 00400:
   case 00440:
-    pcinc(cpu_skip());
+    cpu_ndxp(cpu_skip());
     break;
   case 00500:
   case 00540:
@@ -721,14 +783,96 @@ cpu_insn(void)
     if (history_n < history_m)
       history_n++;
   }
+}
 
-  /* Check for interrupts. */
-  if ((C & 06000) != 06000 && C != 00010 && interrupt && interrupt_enable) {
-    interrupt = interrupt_enable = 0;
-    memaddr(021);
-    memrd();
-    C = B;
+t_stat cpu_do(void)
+{
+  t_stat stat;
+
+  DO = 1;
+  C = LSW;
+  cpu_set_B(RSW);
+  cpu_insn();
+  DO = 0;
+
+  sim_interval = 1;
+  /* Can not return from DO until the instruction is done,
+     i.e. not paused. */
+  while (paused) {
+    AIO_CHECK_EVENT;
+    if (sim_interval <= 0) {
+      if ((stat = sim_process_event()) != SCPE_OK)
+        return stat;
+    }
+    sim_interval--;
+  }
+  return SCPE_OK;
+}
+
+static int jmp_or_eni(void)
+{
+  return (C & 06000) == INSN_JMP || (C == INSN_ENI);
+}
+
+static int mtp_or_opr(void)
+{
+  return (C & 07700) == INSN_MTP || (C & 07700) == INSN_OPR;
+}
+
+static void cpu_interrupt(void)
+{
+  if (!INTREQ)
+    return;
+  if (!ENI)
+    return;
+
+  sim_debug(DBG_INT, &cpu_dev, "Interrupt requested and enabled.\n");
+
+  if (jmp_or_eni()) {
+    sim_debug(DBG_INT, &cpu_dev, "Interrupt not taken after JMP or ENI.\n");
+    return;
+  }
+
+  if (paused) {
+    if (!mtp_or_opr()) {
+      sim_debug(DBG_INT, &cpu_dev, "Pause only interrupted for MTP or OPR.\n");
+      return;
+    }
+    if (PINFF)
+      return;
+    sim_debug(DBG_INT, &cpu_dev, "Pause interrupted.\n");
+    PINFF = 1;
+    paused = 0;
+  }
+
+  sim_debug(DBG_INT, &cpu_dev, "Interrupt taken.\n");
+
+  cpu_set_S(021);
+  cpu_mem_read();
+  C = B;
+  if (history) {
+    history[history_i].P = 07777;
+    history[history_i].C = C;
+    history[history_i].S = S;
+  }
+
+  ENI = 0; /* Except for OPR. */
+  if ((C & 06000) == INSN_JMP)
     cpu_jmp();
+  else if ((C & 07700) == INSN_OPR) {
+    ENI = 1; /* OPR doesn't disable interrupts. */
+    cpu_opr();
+  } else if (C == INSN_NOP)
+    ;
+  else
+    sim_debug(DBG_INT, &cpu_dev, "Invalid interrupt instruction.\n");
+
+  if (history) {
+    history[history_i].B = B;
+    history[history_i].A = A;
+    history_i = (history_i + 1) % history_m;
+    if (history_n < history_m)
+      history_n++;
   }
 }
 
@@ -739,8 +883,18 @@ t_stat sim_instr(void)
   if ((stat = build_dev_tab()) != SCPE_OK)
     return stat;
 
+  /* Stepping is based on sim_step, not sim_interval.  The latter is
+     approximately memory cycles, not instructions. */
+  sim_cancel_step();
+
+  /* Because we check sim_step before cpu_insn. */
+  if (sim_step)
+    sim_step++;
+
   stop_reason = 0;
   paused = 0;
+  PINFF = 0;
+  ENI = 0;
 
   for (;;) {
     AIO_CHECK_EVENT;
@@ -752,19 +906,19 @@ t_stat sim_instr(void)
     if (sim_brk_summ && sim_brk_test(P, SWMASK('E')))
       return STOP_IBKPT;
 
-#if 0
-    if (paused)
-      sim_debug(DBG_CPU, &cpu_dev, "Paused\n");
-#endif
+    /* Can not return from a STEP until the instruction is done,
+       i.e. not paused. */
+    if (!paused && sim_step != 0) {
+      if (--sim_step == 0)
+        return SCPE_STEP;
+    }
+
     if (paused)
       sim_interval--;
     else
       cpu_insn();
 
-    if (sim_step != 0) {
-      if (--sim_step == 0)
-        return SCPE_STEP;
-    }
+    cpu_interrupt();
 
     if (stop_reason)
       return stop_reason;
@@ -828,36 +982,87 @@ cpu_show_hist(FILE *st, UNIT *uptr, int32 val, CONST void *desc)
     j = history_m + history_i - history_n;
 
   for (i = 0; i < history_n; i++) {
-    if (stop_cpu) {                 /* Control-C (SIGINT) */
-      stop_cpu = FALSE;
-      break;                        /* abandon remaining output */
-    }
-    fprintf (st, "%04o %04o %04o %04o %04o %d  ",
-             history[j].P,
+    if (history[j].P == 07777)
+      fprintf (st, "---- ");
+    else
+      fprintf (st, "%04o ", history[j].P);
+    fprintf (st, "%04o %04o %04o %04o %d  ",
              history[j].C,
              history[j].S,
              history[j].B,
              history[j].A,
              history[j].L);
     insn = history[j].C;
-    fprint_sym (st, history[j].P, &insn, NULL, SWMASK ('M'));
-    fputc ('\n', st);
+    fprint_sym(st, history[j].P, &insn, NULL, SWMASK('M'));
+    fputc('\n', st);
     j = (j + 1) % history_m;
   }
 
   return SCPE_OK;
 }
 
-static t_bool pc_is_a_subroutine_call(t_addr **ret_addrs)
-{
-  return FALSE;
-}
-
 static t_stat
 cpu_reset(DEVICE *dptr)
 {
   sim_brk_types = SWMASK('E') | SWMASK('R') | SWMASK('W');
   sim_brk_dflt = SWMASK('E');
-  sim_vm_is_subroutine_call = &pc_is_a_subroutine_call;
+  sim_vm_cmd = linc_cmd;
   return SCPE_OK;
 }
+
+static t_stat linc_boot(int32 flag, CONST char *cptr)
+{
+  char dev[CBUFSIZE], arg[CBUFSIZE];
+  char bbuf[CBUFSIZE], gbuf[CBUFSIZE];
+  t_value block;
+  t_stat stat;
+
+  /* Is it BOOT TAPE? */
+  cptr = get_glyph(cptr, dev, 0);
+  if (*dev == 0)
+    return SCPE_ARG;
+  if (strncmp(dev, "TAPE", 4) != 0)
+    return run_cmd(RU_BOOT, dev);
+
+  /* Yes.  Is there an argument after? */
+  if (*cptr == 0)
+    return run_cmd(RU_BOOT, dev);
+
+  bbuf[0] = 0;
+  strcpy(gbuf, "20");
+  while (*cptr) {
+    cptr = get_glyph(cptr, arg, 0);
+    if (strncmp(arg, "RDC=", 4) == 0)
+      LSW = 0700, strcpy(bbuf, arg + 4);
+    else if (strncmp(arg, "RCG=", 4) == 0)
+      LSW = 0701, strcpy(bbuf, arg + 4);
+    else if (strncmp(arg, "START=", 6) == 0)
+      LSW = 0701, strcpy(gbuf, arg + 6);
+    else
+      return SCPE_ARG;
+  }
+
+  if (*bbuf == 0)
+    return SCPE_ARG;
+
+  /* It's a BOOT TAPE RDC= or RCG=, so start from switches. */
+  block = get_uint(bbuf, 8, ~0, &stat);
+  if (stat != SCPE_OK)
+    return stat;
+
+  RSW = block;
+  stat = cpu_do();
+  if (stat != SCPE_OK)
+    return stat;
+  return run_cmd(RU_GO, gbuf);
+}
+
+static t_stat linc_do(int32 flag, CONST char *cptr)
+{
+  /* With arguments, regular DO to execute script. */
+  if (*cptr != 0)
+    return do_cmd(flag, cptr);
+
+  /* No arguments, push the DO button on the LINC control panel. */
+  return cpu_do();
+}
diff --git a/linc/linc_crt.c b/linc/linc_crt.c
index e3b1cfef..d9d1ab84 100644
--- a/linc/linc_crt.c
+++ b/linc/linc_crt.c
@@ -44,6 +44,7 @@ static UNIT crt_unit = {
 static DEBTAB crt_deb[] = {
   { "DBG",  DBG },
   { "VVID", SIM_VID_DBG_VIDEO },
+  { "KVID", SIM_VID_DBG_KEY },
   { NULL, 0 }
 };
 
@@ -58,7 +59,7 @@ DEVICE crt_dev = {
   1, 8, 12, 1, 8, 12,
   NULL, NULL, &crt_reset,
   NULL, NULL, NULL,
-  NULL, DEV_DISABLE | DEV_DEBUG | DEV_DISPLAY, 0, crt_deb,
+  NULL, DEV_DISABLE | DEV_DEBUG, 0, crt_deb,
   NULL, NULL, NULL, NULL, NULL, NULL
 };
 
@@ -109,14 +110,7 @@ crt_point (uint16 x, uint16 y)
 #endif
 }
 
-/* Hook called when CRT goes idle. */
-void
-crt_idle (void)
-{
-}
-
-/* Display high voltage sync. */
-void
-crt_hvc (void)
+void crt_toggle_fullscreen(void)
 {
+  vid_set_fullscreen(!vid_is_fullscreen ());
 }
diff --git a/linc/linc_defs.h b/linc/linc_defs.h
index c92eac99..a1b9f26e 100644
--- a/linc/linc_defs.h
+++ b/linc/linc_defs.h
@@ -36,6 +36,18 @@
 #define STOP_RBKPT      3
 #define STOP_WBKPT      3
 
+#define WMASK  07777  /* Full word. */
+#define HMASK  04000  /* H bit; half word select. */
+#define AMASK  03777  /* Full memory address. */
+#define XMASK  01777  /* X part; low memory address. */
+#define DMASK  00777  /* Display coordinate. */
+#define TMASK  00777  /* Tape block. */
+#define LMASK  07700  /* Left half word. */
+#define RMASK  00077  /* Right half word; character. */
+#define IMASK  00020  /* Index bit. */
+#define UMASK  00010  /* Tape unit bit. */
+#define BMASK  00017  /* Beta; index register. */
+
 #define MEMSIZE  2048
 
 extern REG cpu_reg[];
@@ -49,10 +61,13 @@ extern DEVICE tape_dev;
 extern DEVICE tty_dev;
 
 extern t_bool build_dev_tab(void);
+extern t_stat cpu_do(void);
 extern void dpy_dis(uint16 h, uint16 x, uint16 y);
 extern void crt_point (uint16 x, uint16 y);
+extern void crt_toggle_fullscreen(void);
 extern uint16 kbd_key(uint16 wait);
 extern int kbd_struck(void);
 extern void tape_op(void);
+extern t_stat tape_metadata(FILE *, uint16 *, int16 *, int16 *);
 
 #endif /* LINC_DEFS_H_ */
diff --git a/linc/linc_kbd.c b/linc/linc_kbd.c
index 8a868400..6a6ae1f8 100644
--- a/linc/linc_kbd.c
+++ b/linc/linc_kbd.c
@@ -4,12 +4,10 @@
 /* Debug */
 #define DBG   0001
 
-static t_stat kbd_svc(UNIT *uptr);
-static t_stat kbd_reset(DEVICE *dptr);
+#define A (*(uint16 *)cpu_reg[2].loc)
+#define paused (*(int *)cpu_reg[11].loc)
 
-static UNIT kbd_unit = {
-  UDATA(&kbd_svc, UNIT_IDLE, 0)
-};
+static t_stat kbd_reset(DEVICE *dptr);
 
 static DEBTAB kbd_deb[] = {
   { "DBG", DBG },
@@ -17,8 +15,8 @@ static DEBTAB kbd_deb[] = {
 };
 
 DEVICE kbd_dev = {
-  "KBD", &kbd_unit, NULL, NULL,
-  1, 8, 12, 1, 8, 12,
+  "KBD", NULL, NULL, NULL,
+  0, 8, 12, 1, 8, 12,
   NULL, NULL, &kbd_reset,
   NULL, NULL, NULL, NULL, DEV_DEBUG, 0, kbd_deb,
   NULL, NULL, NULL, NULL, NULL, NULL
@@ -44,170 +42,6 @@ CASE  0  1  2  3  4  5  6  7  8  9 DEL
 static int kbd_pressed = 0;
 static uint16 kbd_code;
 
-void kbd_translate(int ch)
-{
-  switch (ch) {
-  case '0':
-    kbd_code = 000;
-    break;
-  case '1':
-    kbd_code = 001;
-    break;
-  case '2':
-    kbd_code = 002;
-    break;
-  case '3':
-    kbd_code = 003;
-    break;
-  case '4':
-    kbd_code = 004;
-    break;
-  case '5':
-    kbd_code = 005;
-    break;
-  case '6':
-    kbd_code = 006;
-    break;
-  case '7':
-    kbd_code = 007;
-    break;
-  case '8':
-    kbd_code = 010;
-    break;
-  case '9':
-    kbd_code = 011;
-    break;
-  case '\r': case '\n':
-    kbd_code = 012;
-    break;
-  case '\b': case 0177:
-    kbd_code = 013;
-    break;
-  case ' ':
-    kbd_code = 014;
-    break;
-  case '=': case 'i':
-    kbd_code = 015;
-    break;
-  case 'p': case 'u':
-    kbd_code = 016;
-    break;
-  case ',': case '-':
-    kbd_code = 017;
-    break;
-  case '.': case '+':
-    kbd_code = 020;
-    break;
-/*case '⊟':*/ case '|':
-    kbd_code = 021;
-    break;
-  case '[': case '#':
-    kbd_code = 022;
-    break;
- /*case CASE:*/
-    kbd_code = 023;
-    break;
-  case 'A': case 'a':
-    kbd_code = 024;
-    break;
-  case 'B': case 'b':
-    kbd_code = 025;
-    break;
-  case 'C': case 'c':
-    kbd_code = 026;
-    break;
-  case 'D': case 'd':
-    kbd_code = 027;
-    break;
-  case 'E': case 'e':
-    kbd_code = 030;
-    break;
-  case 'F': case 'f':
-    kbd_code = 031;
-    break;
-  case 'G': case 'g':
-    kbd_code = 032;
-    break;
-  case 'H': case 'h':
-    kbd_code = 033;
-    break;
-  case 'I': /*case 'i':*/
-    kbd_code = 034;
-    break;
-  case 'J': case 'j':
-    kbd_code = 035;
-    break;
-  case 'K': case 'k':
-    kbd_code = 036;
-    break;
-  case 'L': case 'l':
-    kbd_code = 037;
-    break;
-  case 'M': case 'm':
-    kbd_code = 040;
-    break;
-  case 'N': case 'n':
-    kbd_code = 041;
-    break;
-  case 'O': case 'o':
-    kbd_code = 042;
-    break;
-  case 'P': /*case 'p':*/
-    kbd_code = 043;
-    break;
-  case 'Q': case 'q':
-    kbd_code = 044;
-    break;
-  case 'R': case 'r':
-    kbd_code = 045;
-    break;
-  case 'S': case 's':
-    kbd_code = 046;
-    break;
-  case 'T': case 't':
-    kbd_code = 047;
-    break;
-  case 'U': /*case 'u':*/
-    kbd_code = 050;
-    break;
-  case 'V': case 'v':
-    kbd_code = 051;
-    break;
-  case 'W': case 'w':
-    kbd_code = 052;
-    break;
-  case 'X': case 'x':
-    kbd_code = 053;
-    break;
-  case 'Y': case 'y':
-    kbd_code = 054;
-    break;
-  case 'Z': case 'z':
-    kbd_code = 055;
-    break;
-  default:
-    return;
-  }
-  sim_debug(DBG, &kbd_dev, "Key struck %c -> %02o\n", ch, kbd_code);
-  kbd_pressed = 1;
-}
-
-static t_stat kbd_svc(UNIT *uptr)
-{
-  t_stat ch = sim_poll_kbd();
-
-  if ((ch & SCPE_KFLAG) == 0) {
-    sim_activate_after(&kbd_unit, 10000);
-    return ch;
-  }
-
-  if (ch & SCPE_BREAK)
-    ;
-  else
-    kbd_translate(ch & 0177);
-  return SCPE_OK;
-}
-
 int kbd_struck(void)
 {
   if (kbd_pressed)
@@ -219,11 +53,11 @@ uint16 kbd_key(uint16 wait)
 {
   if (kbd_pressed) {
     sim_debug(DBG, &kbd_dev, "KEY %02o\n", kbd_code);
-    sim_activate_abs(&kbd_unit, 1);
     kbd_pressed = 0;
     return kbd_code;
-  } else {
+  } else if (wait) {
     sim_debug(DBG, &kbd_dev, "KEY paused\n");
+    paused = 1;
   }
   return 0;
 }
@@ -399,12 +233,19 @@ static void kbd_convert(uint32 key)
     // ˣ 75
     // : 76
     // ʸ 77
+  case SIM_KEY_F11:
+    crt_toggle_fullscreen();
+    return;
   default:
     return;
   }
   sim_debug(DBG, &kbd_dev, "Key struck %s -> %02o\n",
             vid_key_name(key), kbd_code);
-  kbd_pressed = 1;
+  if (paused)
+    A = kbd_code;
+  else
+    kbd_pressed = 1;
+  paused = 0;
 }
 
 static int
@@ -421,7 +262,6 @@ kbd_reset(DEVICE *dptr)
 #ifdef USE_DISPLAY
   vid_display_kb_event_process = kbd_event;
 #endif
-  sim_activate_abs(&kbd_unit, 0);
 
   return SCPE_OK;
 }
diff --git a/linc/linc_sys.c b/linc/linc_sys.c
index 5bda3e9b..1de0d3ce 100644
--- a/linc/linc_sys.c
+++ b/linc/linc_sys.c
@@ -104,28 +104,35 @@ sim_load(FILE *fileref, CONST char *cptr, CONST char *fnam, int flag)
 {
   t_stat (*get_word)(FILE *fileref, uint16 *x) = get_binary_word;
   t_addr addr, length = MEMSIZE, start = 0, end;
+  int16 forward_offset = 0, reverse_offset;
+  uint16 block_size;
   long offset = 0;
   t_stat stat;
 
+  if (sim_switches & SWMASK('E')) {
+    stat = tape_metadata(fileref, &block_size, &forward_offset, &reverse_offset);
+    if (stat != SCPE_OK)
+      return stat;
+    if (block_size != 256)
+      return SCPE_FMT;
+  }
+
   if (sim_switches & SWMASK('O'))
     get_word = get_octal_word;
 
-  while (cptr != NULL && *cptr != 0) {
-    if (strncasecmp(cptr, "start=", 6) == 0)
-      start = (t_addr)get_uint(cptr + 6, 8, ~0, &stat);
-    else if (strncasecmp(cptr, "offset=", 7) == 0)
-      offset = 2 * (long)get_uint(cptr + 7, 8, ~0, &stat);
-    else if (strncasecmp(cptr, "block=", 6) == 0)
-      offset = 512 * (long)get_uint(cptr + 6, 8, ~0, &stat);
-    else if (strncasecmp(cptr, "length=", 7) == 0)
-      length = (t_addr)get_uint(cptr + 7, 8, ~0, &stat);
+  while (*cptr !=0) {
+    char gbuf[100];
+    cptr = get_glyph(cptr, gbuf, 0);
+    if (strncmp(gbuf, "START=", 6) == 0)
+      start = (t_addr)get_uint(gbuf + 6, 8, ~0, &stat);
+    else if (strncmp(gbuf, "OFFSET=", 7) == 0)
+      offset = 2 * (long)get_uint(gbuf + 7, 8, ~0, &stat);
+    else if (strncmp(gbuf, "BLOCK=", 6) == 0)
+      offset = 512 * ((long)get_uint(gbuf + 6, 8, ~0, &stat) - forward_offset);
+    else if (strncmp(gbuf, "LENGTH=", 7) == 0)
+      length = (t_addr)get_uint(gbuf + 7, 8, ~0, &stat);
     else
       return SCPE_ARG;
-    cptr = strchr(cptr, ' ');
-    if (cptr == NULL)
-      break;
-    while (*cptr == ' ')
-      cptr++;
   }
 
   end = start + length;
@@ -162,7 +169,7 @@ t_bool build_dev_tab(void)
 static t_stat fprint_next(FILE *of, uint16 addr)
 {
   fprintf(of, "\n");
-  fprint_val(of, ++addr & 01777, 8, 10, PV_LEFT);
+  fprint_val(of, ++addr & XMASK, 8, 10, PV_LEFT);
   fprintf(of, ":\t%04o", M[addr]);
   return -1;
 }
@@ -182,8 +189,8 @@ static void fprint_misc(FILE *of, uint16 insn)
   case 00011:
     fprintf(of, "CLR");
     break;
-  case 00013:
-    fprintf(of, "%04o", insn);
+  case 00012:
+    fprintf(of, "DIN");
     break;
   case 00014:
     fprintf(of, "ATR");
@@ -198,17 +205,17 @@ static void fprint_misc(FILE *of, uint16 insn)
     fprintf(of, "COM");
     break;
   default:
-    fprintf(of, "%04o", insn);
+    fprintf(of, "MSC %o", insn);
     break;
   }
 }
 
 static t_stat fprint_index(FILE *of, uint16 insn, uint16 addr)
 {
-  if (insn & 020)
+  if (insn & IMASK)
     fprintf(of, " i");
-  if (insn & 017)
-    fprintf(of, " %o", insn & 017);
+  if (insn & BMASK)
+    fprintf(of, " %o", insn & BMASK);
   else
     return fprint_next(of, addr);
   return SCPE_OK;
@@ -223,7 +230,7 @@ static void fprint_set(FILE *of, uint16 insn, uint16 addr)
 
 static void fprint_sam(FILE *of, uint16 insn)
 {
-  fprintf(of, "SAM ");
+  fprintf(of, "SAM%s %o", insn & IMASK ? " i" : "", insn & BMASK);
 }
 
 static t_stat fprint_dis(FILE *of, uint16 insn, uint16 addr)
@@ -263,7 +270,7 @@ static void fprint_skip(FILE *of, uint16 insn)
   case 000: case 001: case 002: case 003: case 004: case 005: case 006: case 007:
   case 010: case 011: case 012: case 013:
     fprintf(of, "SXL");
-    snprintf(beta, sizeof beta, "%o", insn & 017);
+    snprintf(beta, sizeof beta, "%o", insn & BMASK);
     break;
   case 015:
     fprintf(of, "KST");
@@ -297,7 +304,7 @@ static void fprint_skip(FILE *of, uint16 insn)
     fprintf(of, "%04o", insn);
     return;
   }
-  if (insn & 020)
+  if (insn & IMASK)
     fprintf(of, " i" );
   fprintf(of, " %s", beta);
 }
@@ -322,7 +329,7 @@ static void fprint_opr(FILE *of, uint16 insn)
     fprintf(of, "%04o", insn);
     break;
   }
-  if (insn & 020)
+  if (insn & IMASK)
     fprintf(of, "i" );
 }
 
@@ -364,9 +371,9 @@ static void fprint_tape(FILE *of, uint16 insn, uint16 addr)
     fprintf(of, "CHK");
     break;
   }
-  if (insn & 020)
+  if (insn & IMASK)
     fprintf(of, " i");
-  if (insn & 010)
+  if (insn & UMASK)
     fprintf(of, " u");
   fprint_next(of, addr);
 }
@@ -463,17 +470,17 @@ static t_stat fprint_dsc(FILE *of, uint16 insn, uint16 addr)
 
 static void fprint_add(FILE *of, uint16 insn)
 {
-  fprintf(of, "ADD %04o", insn & 01777);
+  fprintf(of, "ADD %04o", insn & XMASK);
 }
 
 static void fprint_stc(FILE *of, uint16 insn)
 {
-  fprintf(of, "STC %04o", insn & 01777);
+  fprintf(of, "STC %04o", insn & XMASK);
 }
 
 static void fprint_jmp(FILE *of, uint16 insn)
 {
-  fprintf(of, "JMP %04o", insn & 01777);
+  fprintf(of, "JMP %04o", insn & XMASK);
 }
 
 t_stat fprint_sym(FILE *of, t_addr addr, t_value *val, UNIT *uptr, int32 sw)
@@ -582,12 +589,108 @@ t_stat fprint_sym(FILE *of, t_addr addr, t_value *val, UNIT *uptr, int32 sw)
   return SCPE_OK;
 }
 
+struct symbol {
+  const char *name;
+  uint16 value;
+};
+
+static const struct symbol symbols[] = {
+  { "U",   00010 },
+  { "I",   00020 },
+  { "HLT", 00000 },
+  { "ZTA", 00005 },
+  { "CLR", 00011 },
+  { "DIN", 00012 },
+  { "ATR", 00014 },
+  { "RTA", 00015 },
+  { "NOP", 00016 },
+  { "COM", 00017 },
+  { "SET", 00040 },
+  { "SAM", 00100 },
+  { "DIS", 00140 },
+  { "XSK", 00200 },
+  { "ROL", 00240 },
+  { "ROR", 00300 },
+  { "SCR", 00340 },
+  { "SXL", 00400 },
+  { "KST", 00415 },
+  { "SNS", 00440 },
+  { "AZE", 00450 },
+  { "APO", 00451 },
+  { "LZE", 00452 },
+  { "IBZ", 00453 },
+  { "OVF", 00454 },
+  { "ZZZ", 00455 },
+  { "OPR", 00500 },
+  { "KBD", 00515 },
+  { "RSW", 00516 },
+  { "LSW", 00517 },
+  { "LMB", 00600 },
+  { "UMB", 00640 },
+  { "RDC", 00700 },
+  { "RCG", 00701 },
+  { "RDE", 00702 },
+  { "MTB", 00703 },
+  { "WRC", 00704 },
+  { "WCG", 00705 },
+  { "WRI", 00706 },
+  { "CHK", 00707 },
+  { "LDA", 01000 },
+  { "STA", 01040 },
+  { "ADA", 01100 },
+  { "ADM", 01140 },
+  { "LAM", 01200 },
+  { "MUL", 01240 },
+  { "LDH", 01300 },
+  { "STH", 01340 },
+  { "SHD", 01400 },
+  { "SAE", 01440 },
+  { "SRO", 01500 },
+  { "BCL", 01540 },
+  { "BSE", 01600 },
+  { "BCO", 01640 },
+  { "DSC", 01740 },
+  { "ADD", 02000 },
+  { "STC", 04000 },
+  { "JMP", 06000 }
+};
+
 t_stat parse_sym(CONST char *cptr, t_addr addr, UNIT *uptr,
                   t_value *val, int32 sw)
 {
+  char gbuf[CBUFSIZE];
+  t_value val2;
   t_stat stat;
+  int i;
+
   *val = get_uint(cptr, 8, ~0, &stat);
-  if (stat != SCPE_OK)
-    return stat;
-  return 0;
+  if (*val > 07777)
+    return SCPE_ARG;
+  if (stat == SCPE_OK)
+    return SCPE_OK;
+
+  if (*cptr == '-') {
+    stat = parse_sym(cptr + 1, addr, uptr, val, sw);
+    if (stat != SCPE_OK)
+      return stat;
+    *val ^= 07777;
+    if (stat == SCPE_OK)
+      return SCPE_OK;
+  }
+
+  cptr = get_glyph(cptr, gbuf, 0);
+  for (i = 0; i < sizeof symbols / sizeof symbols[0]; i++) {
+    if (strcmp(gbuf, symbols[i].name) != 0)
+      continue;
+    *val = symbols[i].value;
+    if (*cptr) {
+      stat = parse_sym(cptr, addr, uptr, &val2, sw);
+      if (stat != SCPE_OK)
+        return stat;
+      *val |= val2;
+    }
+    return SCPE_OK;
+  }
+
+  return SCPE_ARG;
 }
diff --git a/linc/linc_tape.c b/linc/linc_tape.c
index 4692eb15..f5014769 100644
--- a/linc/linc_tape.c
+++ b/linc/linc_tape.c
@@ -5,10 +5,13 @@
 #define ACC     u5
 #define OFFSET  u6
 
+#define P (*(uint16 *)cpu_reg[0].loc)
 #define C (*(uint16 *)cpu_reg[1].loc)
 #define A (*(uint16 *)cpu_reg[2].loc)
 #define S (*(uint16 *)cpu_reg[6].loc)
 #define B (*(uint16 *)cpu_reg[7].loc)
+#define LSW (*(uint16 *)cpu_reg[8].loc)
+#define RSW (*(uint16 *)cpu_reg[9].loc)
 #define paused (*(int *)cpu_reg[11].loc)
 #define IBZ (*(int *)cpu_reg[12].loc)
 
@@ -24,6 +27,8 @@
 #define MAX_BLOCKS   512
 #define MAX_POS      ((BLOCK_WORDS * MAX_BLOCKS + IBZ_WORDS) * MAX_SPEED)
 
+#define GOOD_CHECKSUM  07777
+
 #define RDC  0  /* read tape and check */
 #define RCG  1  /* read tape group */
 #define RDE  2  /* read tape */
@@ -100,10 +105,10 @@ void tape_op(void)
     uptr->ACC = ACC_START;
   }
   if (!sim_is_active(uptr))
-    sim_activate_after(uptr, 1);
+    sim_activate(uptr, 20);
   paused = 1;
   A = 0;
-  WANTED_BLOCK = B & 0777;
+  WANTED_BLOCK = B & TMASK;
 
   switch (C & 7) {
   case RDC: case RDE: case WRC: case WRI: case CHK:
@@ -124,25 +129,25 @@ void tape_op(void)
   }
 }
 
-static t_stat tape_seek(UNIT *uptr, t_addr block, t_addr offset)
+static t_stat tape_seek(FILE *fileref, t_addr block, t_addr offset)
 {
   offset = DATA_WORDS * block + offset;
   offset *= 2;
-  if (sim_fseek(uptr->fileref, offset, SEEK_SET) == -1)
+  if (sim_fseek(fileref, offset, SEEK_SET) == -1)
     return SCPE_IOERR;
   return SCPE_OK;
 }
 
-static uint16 read_word(UNIT *uptr, t_addr block, t_addr offset)
+static uint16 read_word(FILE *fileref, t_addr block, t_addr offset)
 {
   t_stat stat;
   uint8 data[2];
   uint16 word;
 
-  stat = tape_seek(uptr, block, offset);
+  stat = tape_seek(fileref, block, offset);
   if (stat != SCPE_OK)
     ;
-  if (sim_fread(data, 1, 2, uptr->fileref) != 2)
+  if (sim_fread(data, 1, 2, fileref) != 2)
     ;
   if (data[1] & 0xF0)
     ;
@@ -152,17 +157,17 @@ static uint16 read_word(UNIT *uptr, t_addr block, t_addr offset)
   return word;
 }
 
-static void write_word(UNIT *uptr, t_addr block, t_addr offset, uint16 word)
+static void write_word(FILE *fileref, t_addr block, t_addr offset, uint16 word)
 {
   t_stat stat;
   uint8 data[2];
 
-  stat = tape_seek(uptr, block, offset);
+  stat = tape_seek(fileref, block, offset);
   if (stat != SCPE_OK)
     ;
   data[0] = word & 0xFF;
   data[1] = word >> 8;
-  if (sim_fwrite(data, 1, 2, uptr->fileref) != 2)
+  if (sim_fwrite(data, 1, 2, fileref) != 2)
     ;
 }
 
@@ -197,23 +202,22 @@ static void tape_done(UNIT *uptr)
 
   switch (C & 7) {
   case RDC: case RCG: case RDE: case CHK:
-    A = 07777;
+    A = GOOD_CHECKSUM;
     break;
   case WRI:
-    A = A ^ 07777;
-    A++;
-    A &= 07777;
+    A = (A ^ 07777) + 1;
+    A &= WMASK;
     break;
   case MTB:
     A = (WANTED_BLOCK + ~CURRENT_BLOCK);
     A += A >> 12;
-    A &= 07777;
+    A &= WMASK;
     break;
   }
 
   switch (C & 7) {
   case RDC:
-    if (A != 07777) {
+    if (A != GOOD_CHECKSUM) {
       sim_debug(DBG, &tape_dev, "Check failed; read again\n");
       S &= ~0377;
     } else {
@@ -224,7 +228,7 @@ static void tape_done(UNIT *uptr)
   case WRC:
     sim_debug(DBG, &tape_dev, "Block written, go back and check\n");
     // For now, done.
-    A = 07777;
+    A = GOOD_CHECKSUM;
     paused = 0;
     break;
   case RCG: case WCG:
@@ -235,7 +239,7 @@ static void tape_done(UNIT *uptr)
       sim_debug(DBG, &tape_dev, "Blocks left in group: %d\n", GROUP);
       GROUP--;
     }
-    WANTED_BLOCK = (WANTED_BLOCK + 1) & 0777;
+    WANTED_BLOCK = (WANTED_BLOCK + 1) & TMASK;
     break;
   case RDE: case WRI:
     sim_debug(DBG, &tape_dev, "Transfer done\n");
@@ -253,7 +257,7 @@ static void tape_done(UNIT *uptr)
 
   if (paused)
     ;
-  else if ((C & 020) == 0) {
+  else if ((C & IMASK) == 0) {
     sim_debug(DBG_SEEK, &tape_dev, "Instruction done, stop tape\n");
     uptr->ACC = uptr->SPEED > 0 ? -ACC_STOP : ACC_STOP;
   } else {
@@ -265,7 +269,7 @@ static void tape_word(UNIT *uptr, uint16 block, uint16 offset)
 {
   switch (C & 7) {
   case RDC: case RCG: case RDE: case CHK:
-    B = read_word(uptr, block, offset);
+    B = read_word(uptr->fileref, block, offset);
     sim_debug(DBG_READ, &tape_dev,
               "Read block %03o offset %03o data %04o address %04o\n",
               block, offset, B, S);
@@ -277,12 +281,12 @@ static void tape_word(UNIT *uptr, uint16 block, uint16 offset)
     sim_debug(DBG_WRITE, &tape_dev,
               "Write block %03o offset %03o data %04o address %04o\n",
               block, offset, B, S);
-    write_word(uptr, block, offset, B);
+    write_word(uptr->fileref, block, offset, B);
     break;
   }
-  S = (S+1) & 03777;
+  S = (S+1) & AMASK;
   A += B;
-  A &= 07777;
+  A &= WMASK;
 }
 
 static t_stat tape_svc(UNIT *uptr)
@@ -384,43 +388,70 @@ static t_stat tape_reset(DEVICE *dptr)
 
 static t_stat tape_boot(int32 unit_num, DEVICE *dptr)
 {
+  uint16 block = 0300;
+  uint16 blocks = 8;
+  uint16 quarter = 0;
+  t_stat stat;
+
   if (unit_num >= 2 && unit_num <= 3)
     return SCPE_ARG;
+  if (blocks == 0)
+    return SCPE_ARG;
+    
+  if (blocks == 1)
+    LSW = RDC;
+  else
+    LSW = RCG, quarter = blocks - 1;
+  LSW |= 0700 | (unit_num << 3);
+  RSW = (quarter << 9) | block;
+  stat = cpu_do();
+  if (stat != SCPE_OK)
+    return stat;
+  P = 020;
+  return SCPE_OK;
+}
 
-  //LSW = 0701 + (unit_num << 3);
-  //RSW = (7 << 9) | 0300;
-  //P = 020;
+t_stat tape_metadata(FILE *fileref, uint16 *block_size, int16 *forward_offset, int16 *reverse_offset)
+{
+  t_offset size = sim_fsize(fileref);
+  if (size == MAX_BLOCKS * DATA_WORDS * 2) {
+    /* Plain image. */
+    *block_size = DATA_WORDS;
+    *forward_offset = 0;
+    *reverse_offset = 0;
+  } else if ((size % (2 * DATA_WORDS)) == 6) {
+    /* Extended image with additional meta data. */
+    uint16 metadata = (uint16)(size / (2 * DATA_WORDS));
+    *block_size = read_word(fileref, metadata, 0);
+    *forward_offset = (int16)read_word(fileref, metadata, 1);
+    *reverse_offset = (int16)read_word(fileref, metadata, 2);
+  } else
+    return SCPE_FMT;
   return SCPE_OK;
 }
 
 static t_stat tape_attach(UNIT *uptr, CONST char *cptr)
 {
   t_stat stat;
-  t_offset size;
+  uint16 block_size;
+  int16 forward_offset, reverse_offset;
+
   if (uptr - tape_unit >= 2 && uptr - tape_unit <= 3)
     return SCPE_ARG;
   stat = attach_unit(uptr, cptr);
   if (stat != SCPE_OK)
     return stat;
-  size = sim_fsize(uptr->fileref);
-  if (size == MAX_BLOCKS * DATA_WORDS * 2)
-    uptr->OFFSET = 0; /* Plain image. */
-  else if ((size % (2 * DATA_WORDS)) == 6) {
-    /* Extended image with additional meta data. */
-    uint16 metadata = (uint16)(size / (2 * DATA_WORDS));
-    uint16 block_size = read_word(uptr, metadata, 0);
-    int16 forward_offset = (int16)read_word(uptr, metadata, 1);
-    int16 reverse_offset = (int16)read_word(uptr, metadata, 2);
-    sim_debug(DBG, &tape_dev,
-              "Extended image with block size %o, block offset %d/%d\r\n",
-              block_size, forward_offset, reverse_offset);
-    if (block_size != DATA_WORDS)
-      return SCPE_FMT;
-    if (forward_offset != reverse_offset)
-      return SCPE_FMT;
-    uptr->OFFSET = forward_offset;
-  } else
+  stat = tape_metadata(uptr->fileref, &block_size, &forward_offset, &reverse_offset);
+  if (stat != SCPE_OK)
+    return stat;
+  sim_debug(DBG, &tape_dev,
+            "Tape image with block size %o, block offset %d/%d\r\n",
+            block_size, forward_offset, reverse_offset);
+  if (block_size != DATA_WORDS)
     return SCPE_FMT;
+  if (forward_offset != reverse_offset)
+    return SCPE_FMT;
+  uptr->OFFSET = forward_offset;
     
   uptr->POS = -2 * START_POS;
   uptr->SPEED = 0;
diff --git a/linc/linc_tty.c b/linc/linc_tty.c
index 8979d2ae..89044e8c 100644
--- a/linc/linc_tty.c
+++ b/linc/linc_tty.c
@@ -1,6 +1,124 @@
 #include "linc_defs.h"
 
-DEVICE tty_dev = {
-  "TTY", NULL, NULL, NULL,
-  0, 8, 12, 1, 8, 12,
+
+/* Data bits, 110 baud rate. */
+#define BIT_TIME       1120
+/* Sample rate to find the start bit edge. */
+#define START_TIME     (BIT_TIME / 5)
+/* After finding the edge, wait until the middle of the first data bit. */
+#define FIRST_TIME     (BIT_TIME + (BIT_TIME - START_TIME) / 2)
+
+#define R (*(uint16 *)cpu_reg[5].loc)
+
+/* Debug */
+#define DBG             0001
+#define DBG_BIT         0002
+
+#define DATA      u3    /* Character being assembled. */
+#define STATE     u4    /* 0 for start bit, 1 for stop bit, otherwise data. */
+#define PREVIOUS  u5    /* Previous level seen. */
+
+/* When a start bit is found, the state is set to 10 and then
+   decremented for each bit that is processed. */
+#define STATE_START   0
+#define STATE_STOP    1
+/*      STATE_DATA    2-9 */
+#define STATE_FIRST   10
+
+/* Function declaration. */
+static t_stat tty_svc(UNIT *uptr);
+static t_stat tty_attach(UNIT *uptr, CONST char *cptr);
+static t_stat tty_detach(UNIT *uptr);
+
+static UNIT tty_unit = {
+  UDATA(&tty_svc, UNIT_IDLE | UNIT_ATTABLE, 0)
 };
+
+static DEBTAB tty_deb[] = {
+  { "DBG",  DBG },
+  { "BIT",  DBG_BIT },
+  { NULL, 0 }
+};
+
+DEVICE tty_dev = {
+  "TTY", &tty_unit, NULL, NULL,
+  1, 8, 12, 1, 8, 12,
+  NULL, NULL, NULL,
+  NULL, &tty_attach, &tty_detach,
+  NULL, DEV_DISABLE | DEV_DEBUG, 0, tty_deb,
+  NULL, NULL, NULL, NULL, NULL, NULL
+};
+
+static void tty_output(UNIT *uptr)
+{
+  uint8 ch = uptr->DATA;
+  sim_debug(DBG, &tty_dev, "Character %03o '%c'\n", ch, ch & 0177);
+  fputc(ch & 0177, uptr->fileref);
+  fflush(uptr->fileref);
+}
+
+static t_stat tty_svc(UNIT *uptr)
+{
+  switch (uptr->STATE) {
+  case STATE_START:
+    if (uptr->PREVIOUS == 0 || (R & 1) == 1) {
+      /* Keep looking for start bit. */
+      uptr->PREVIOUS = R & 1;
+      sim_activate(uptr, START_TIME);
+      return SCPE_OK;
+    }
+
+    sim_debug(DBG_BIT, &tty_dev, "Start bit edge found.\n");
+    uptr->STATE = STATE_FIRST;
+    uptr->DATA = 0;
+    /* Wait until the middle of the first data bit.  Since the edge
+       was just seen, this is a little longer than the time between
+       data bits. */
+    sim_activate(uptr, FIRST_TIME);
+    break;
+
+  default:
+    sim_debug(DBG_BIT, &tty_dev, "Data bit %d is %d\n",
+              STATE_FIRST - 1 - uptr->STATE, R & 1);
+    uptr->DATA >>= 1;
+    uptr->DATA |= (R & 1) << 7;
+    sim_activate(uptr, BIT_TIME);
+    break;
+
+  case STATE_STOP:
+    sim_debug(DBG_BIT, &tty_dev, "Stop bit is %d\n", R & 1);
+    if (R & 1)
+      tty_output(uptr);
+    else
+      sim_debug(DBG, &tty_dev, "Framing error.\n");
+    uptr->PREVIOUS = R & 1;
+    /* Look for next start bit. */
+    sim_activate(uptr, START_TIME);
+    break;
+  }
+
+  /* Decrease the state counter, first through the data bits, then
+     the stop bit, and finally the start bit. */
+  uptr->STATE--;
+  return SCPE_OK;
+}
+
+static t_stat tty_attach(UNIT *uptr, CONST char *cptr)
+{
+  t_stat stat = attach_unit(uptr, cptr);
+  if (stat != SCPE_OK)
+    return stat;
+  uptr->STATE = 0;
+  uptr->PREVIOUS = 0;
+  sim_activate(uptr, 1);
+  return SCPE_OK;
+}
+
+static t_stat tty_detach(UNIT *uptr)
+{
+  if ((uptr->flags & UNIT_ATT) == 0)
+    return SCPE_OK;
+  if (sim_is_active(uptr))
+    sim_cancel(uptr);
+  return detach_unit(uptr);
+}
diff --git a/linc/tests/classic-test.do b/linc/tests/classic-test.do
index 071760f8..859ff404 100644
--- a/linc/tests/classic-test.do
+++ b/linc/tests/classic-test.do
@@ -1,106 +1,110 @@
+cd %~p0
+
 # The tests check writing to the tape, so use a copy.
 copy classic-test.linc clobbered.linc
 attach tape0 clobbered.linc
 
 echo CONTRL
-load classic-test.linc block=10 start=0 length=400
+load -e classic-test.linc block=0 start=0 length=400
 break 34
 
 # Special treatment for this test, because it's supposed to halt.
 echo *** Test: 70 - HLTTST ***
-load classic-test.linc block=11 start=400 length=400
+load -e classic-test.linc block=1 start=400 length=400
 assert 400==70
 go 401
 assert P==402
 continue
 assert P==34
 
-call test   1 SAETST 012 002
-call test   2 BCLTST 013 003
-call test   3 BSETST 014 004
-call test   4 BCOTST 015 005
-call test   5 ROTL1  016 006
-call test   6 ROTL2  017 007
-call test   7 ROTL3  020 010
-call test  10 ROTL4  021 011
-call test  11 ROTL5  022 012
-call test  12 ROTR1  023 013
-call test  13 ROTR2  024 014
-call test  14 ROTR3  025 015
-call test  15 ROTR4  026 016
-call test  16 ROTR5  027 017
-call test  17 CLRTST 030 020
-call test  20 ADDONE 031 021
-call test  21 COMT1  032 022
-call test  22 SCRT1  033 023
-call test  23 SCRT2  034 024
-call test  24 SCRT3  035 025
-call test  25 SCRT4  037 027
-call test  26 ADDT1  041 031
-call test  27 FADRT1 042 032
-call test  30 FADRT2 043 033
-call test  31 iBETA1 045 035
-call test  32 iBETA2 046 036
-call test  33 iBETA3 047 037
-call test  34 iBETA4 050 040
-call test  35 LDAT1  051 041
-call test  36 STAT1  052 042
-call test  37 ADMT1  053 043
-call test  40 LAMT1  054 044
-call test  41 MULT1  055 045
-call test  42 SROT1  056 046
-call test  43 SETT1  057 047
-call test  44 SETT2  060 050
-call test  45 XSKT1  061 051
-call test  46 XSKT2  062 052
-call test  47 AZET1  063 053
-call test  50 APOT1  064 054
-call test  51 LZET1  065 055
-call test  52 HWCT1  066 056
-call test  53 HWCT2  067 057
-call test  54 HWCT3  070 060
-call test  55 HWCT4  071 061
-call test  56 HWCT5  072 062
-call test  57 RANADD 073 063
-call test  60 ATRT1  074 064
-call test  61 IBZT1  075 065
-call test  62 JMPUP  076 066
-call test  63 JMPDWN 077 067
-call test  64 TAPETS 100 070
-call test  65 MTBTST 111 101
-call test  66 DISTST 112 102
-call test  67 DSCTST 113 103
-call test 700 OVFT1  114 104
-call test 701 ZTAT1  115 105
-call test 702 ZCLR1  116 106
-deposit SAM[0] 177
-call test 703 ZCLRT2 117 107
-;call test 704 ENIT1  120 110
 deposit RSW 0300
 deposit LSW 0700
 deposit SSW 77
-deposit XL[0] 1
-deposit XL[1] 1
-deposit XL[2] 1
-deposit XL[3] 1
-deposit XL[4] 1
-deposit XL[5] 1
-deposit XL[6] 1
-deposit XL[7] 1
-deposit XL[8] 1
-deposit XL[9] 1
+deposit SAM[0] 177
+deposit XL[0]  1
+deposit XL[1]  1
+deposit XL[2]  1
+deposit XL[3]  1
+deposit XL[4]  1
+deposit XL[5]  1
+deposit XL[6]  1
+deposit XL[7]  1
+deposit XL[8]  1
+deposit XL[9]  1
 deposit XL[10] 1
 deposit XL[11] 1
-call test  71 MISCTS 121 111
+
+call test   1 SAETST 002
+call test   2 BCLTST 003
+call test   3 BSETST 004
+call test   4 BCOTST 005
+call test   5 ROTL1  006
+call test   6 ROTL2  007
+call test   7 ROTL3  010
+call test  10 ROTL4  011
+call test  11 ROTL5  012
+call test  12 ROTR1  013
+call test  13 ROTR2  014
+call test  14 ROTR3  015
+call test  15 ROTR4  016
+call test  16 ROTR5  017
+call test  17 CLRTST 020
+call test  20 ADDONE 021
+call test  21 COMT1  022
+call test  22 SCRT1  023
+call test  23 SCRT2  024
+call test  24 SCRT3  025
+call test  25 SCRT4  027
+call test  26 ADDT1  031
+call test  27 FADRT1 032
+call test  30 FADRT2 033
+call test  31 iBETA1 035
+call test  32 iBETA2 036
+call test  33 iBETA3 037
+call test  34 iBETA4 040
+call test  35 LDAT1  041
+call test  36 STAT1  042
+call test  37 ADMT1  043
+call test  40 LAMT1  044
+call test  41 MULT1  045
+call test  42 SROT1  046
+call test  43 SETT1  047
+call test  44 SETT2  050
+call test  45 XSKT1  051
+call test  46 XSKT2  052
+call test  47 AZET1  053
+call test  50 APOT1  054
+call test  51 LZET1  055
+call test  52 HWCT1  056
+call test  53 HWCT2  057
+call test  54 HWCT3  060
+call test  55 HWCT4  061
+call test  56 HWCT5  062
+call test  57 RANADD 063
+call test  60 ATRT1  064
+call test  61 IBZT1  065
+call test  62 JMPUP  066
+call test  63 JMPDWN 067
+call test  64 TAPETS 070
+call test  65 MTBTST 101
+call test  66 DISTST 102
+call test  67 DSCTST 103
+call test 700 OVFT1  104
+call test 701 ZTAT1  105
+call test 702 ZCLR1  106
+call test 703 ZCLRT2 107
+deposit INTREQ 1
+call test 704 ENIT1  110
+call test  71 MISCTS 111
 
 echo DIAGNOSTICS PASSED
 quit
 
 :test
 echo *** Test: %1 - %2 ***
-load classic-test.linc block=%3 start=400 length=400
+load -e classic-test.linc block=%3 start=400 length=400
 assert 400==%1
-deposit 21 1%4
+deposit 21 1%3
 go 401
 assert P==34
 return
diff --git a/linc/tests/linc_test.ini b/linc/tests/linc_test.ini
index 2aa23d1f..7fede77e 100644
--- a/linc/tests/linc_test.ini
+++ b/linc/tests/linc_test.ini
@@ -1,4 +1,4 @@
-cd linc/tests
+cd %~p0
 set crt disabled
 reset
 do classic-test.do
diff --git a/linc/tests/tty.do b/linc/tests/tty.do
new file mode 100644
index 00000000..b70a3008
--- /dev/null
+++ b/linc/tests/tty.do
@@ -0,0 +1,53 @@
+SET CRT DISABLED
+RESET
+DELETE printer.txt
+ATTACH TTY printer.txt
+DEPOSIT 0020 RTA
+DEPOSIT 0021 BSE i
+DEPOSIT 0022  1
+DEPOSIT 0023 ATR
+DEPOSIT 0024 SET i 12
+DEPOSIT 0025  -430
+DEPOSIT 0026 XSK i 12
+DEPOSIT 0027  JMP 26
+DEPOSIT 0030 SET i 1
+DEPOSIT 0031  57
+DEPOSIT 0032 SET i 2
+DEPOSIT 0033  -20
+DEPOSIT 0034 LDA i 1
+DEPOSIT 0035 STC 44
+DEPOSIT 0036 RTA
+DEPOSIT 0037 SET i 11
+DEPOSIT 0040  -13
+DEPOSIT 0041 BCL i
+DEPOSIT 0042  1
+DEPOSIT 0043 SRO i
+DEPOSIT 0045 ADD 42
+DEPOSIT 0046 ATR
+DEPOSIT 0047 SET i 12
+DEPOSIT 0050  -430
+DEPOSIT 0051 XSK i 12
+DEPOSIT 0052  JMP 51
+DEPOSIT 0053 XSK i 11
+DEPOSIT 0054  JMP 41
+DEPOSIT 0055 XSK i 2
+DEPOSIT 0056  JMP 34
+DEPOSIT 0057 HLT
+DEPOSIT 0060 3220
+DEPOSIT 0061 3212
+DEPOSIT 0062 3230
+DEPOSIT 0063 3230
+DEPOSIT 0064 3236
+DEPOSIT 0065 3100
+DEPOSIT 0066 3250
+DEPOSIT 0067 3212
+DEPOSIT 0070 3230
+DEPOSIT 0071 3212
+DEPOSIT 0072 3250
+DEPOSIT 0073 3262
+DEPOSIT 0074 3240
+DEPOSIT 0075 3212
+DEPOSIT 0076 3032
+DEPOSIT 0077 3024
+GO 20
+QUIT
diff --git a/linc/tests/tty.lap6 b/linc/tests/tty.lap6
new file mode 100644
index 00000000..fefd4cdd
--- /dev/null
+++ b/linc/tests/tty.lap6
@@ -0,0 +1,53 @@
+	@20
+	RTA
+	BSE i	 [MARK STATE
+	 1
+	ATR
+	SET i 12 [GIVE TTY TIME
+	 -430
+	XSK i 12
+	 JMP p-1
+	SET i 1	 [TEXT DATA
+	 2A-1
+	SET i 2	 [TEXT LENGTH
+	 2A-2B
+#1A	LDA i 1	 [GET NEXT CHARACTER
+	STC 1D
+	RTA
+	SET i 11 [OUTPUT 11 BITS
+	 -13	 [1 START, 8 DATA
+#1B	BCL i	 [AND 2 STOP
+#1C	 1
+	SRO i
+#1D
+	ADD 1C
+	ATR	 [OUTPUT BIT TO RELAY
+	SET i 12
+	 -430    [DELAY FOR 110 BAUD
+	XSK i 12
+	 JMP p-1
+	XSK i 11
+	 JMP 1B	 [NEXT BIT
+	XSK i 2
+	 JMP 1A	 [NEXT CHARACTER
+	HLT
+
+	[ASCII TEXT WITH ONE 0 START
+	[BIT AND TWO 1 STOP BITS
+#2A	3220 [H
+	3212 [E
+	3230 [L
+	3230 [L
+	3236 [O
+	3100 [ 
+	3250 [T
+	3212 [E
+	3230 [L
+	3212 [E
+	3250 [T
+	3262 [Y
+	3240 [P
+	3212 [E
+	3032 [CR
+	3024 [LF
+#2B