Worked around initConnection() failures due to machines that initialize more slowly, by also allowing each machine to invoke the other's initConnection(); if it turns out to be unnecessary, it's simply ignored

_config.yml

@@ -5,7 +5,7 @@ email: Jeff@pcjs.org
 description: >
   PCjs: Home of the original IBM PC emulator in a browser.
   Classic computer simulations in JavaScript, including the IBM PC and other x86-based machines, 6502-based
-  machines such as the Ohio Scientific Challenger 1P, and 8080-based machines such as Space Invaders. 
+  machines such as the Ohio Scientific Challenger 1P, and 8080-based machines such as Space Invaders and the DEC VT100 Terminal. 
   Includes an archive of historical PC software and publications.
 baseurl: ""                 # "/pcjs" when using http://jeffpar.github.io or "" when using http://www.pcjs.org 
 url: "http://www.pcjs.org"  # "http://jeffpar.github.io" or "http://www.pcjs.org"
@@ -32,7 +32,7 @@ gems:
 
 pcjs:
   domain: pcjs.org    # whereas site.url is used for linking purposes, site.pcjs.domain is used for display purposes
-  version: 1.23.3     # IMPORTANT: keep pcjs.version in sync with package.json:version
+  version: 1.24.0     # IMPORTANT: keep pcjs.version in sync with package.json:version
   compiled: true      # by default, the compiled pcjs.version scripts will be used (eg, pcx86.js or pcx86-dbg.js)
   c1p_scripts:        # if pcjs.compiled is false, the following scripts will be included instead, in the order listed
     - /modules/shared/lib/defines.js
@@ -94,8 +94,8 @@ pcjs:
     - /modules/pcx86/lib/fdc.js
     - /modules/pcx86/lib/hdc.js
     - /modules/pcx86/lib/debugger.js
-    - /modules/pcx86/lib/state.js
     - /modules/pcx86/lib/computer.js
+    - /modules/shared/lib/state.js
     - /modules/shared/lib/embed.js
     - /modules/shared/lib/save.js
   pc8080_scripts:
@@ -123,7 +123,7 @@ pcjs:
     - /modules/pc8080/lib/video.js
     - /modules/pc8080/lib/serialport.js
     - /modules/pc8080/lib/debugger.js
-    - /modules/pc8080/lib/state.js
     - /modules/pc8080/lib/computer.js
+    - /modules/shared/lib/state.js
     - /modules/shared/lib/embed.js
     - /modules/shared/lib/save.js

_posts/2016-08-19-connecting-an-ibm-pc-to-a-dec-vt100-terminal.md

@@ -0,0 +1,85 @@
+---
+layout: post
+title: Connecting an IBM PC to a DEC VT100 Terminal
+date: 2016-08-19 10:00:00
+permalink: /blog/2016/08/19/
+machines:
+  - id: ibm5170
+    type: pcx86
+    connection: com2->vt100.serialPort
+    config: /devices/pcx86/machine/5170/ega/2048kb/rev3/machine.xml
+  - id: vt100
+    type: pc8080
+    connection: serialPort->ibm5170.com2
+    config: /devices/pc8080/machine/vt100/machine.xml
+---
+
+Now that you've had a chance to play with a standalone [VT100 Terminal](/devices/pc8080/machine/vt100/), not to mention
+[Dual VT100 Terminals](/devices/pc8080/machine/vt100/dual/), it's time to take [PCjs Machines](/) to the next level, and
+begin connecting PCs to terminals.
+
+Below you'll find an 80286-based [IBM PC AT](/devices/pcx86/machine/5170/ega/2048kb/rev3/) connected to an 8080-based
+[VT100 Terminal](/devices/pc8080/machine/vt100/) via the PC's **COM2** serial port.
+
+At this point, the connection is *very* thin.  The [PCx86](/modules/pcx86/) [SerialPort](/modules/pcx86/lib/serialport.js)
+and [PC8080](/modules/pc8080/) [SerialPort](/modules/pc8080/lib/serialport.js) each export exactly two methods:
+
+- *initConnection()*
+- *receiveData()*
+
+The *receiveData()* method always returns *success*, because both SerialPort components buffer all received data.
+For now, the VT100 SerialPort component avoids overflowing the VT100 firmware's buffers by automatically throttling the flow
+of data whenever the firmware, in desperation, issues an XOFF.  This "Auto XOFF" behavior will eventually be superseded by
+additional interfaces that provide conventional RS-232 signal-based flow control.
+
+What can you do with these machines?  Click on the PC screen and type:
+
+	DIR > COM2
+
+or any command redirected to COM2.  The output should appear on the VT100's screen.
+
+A more interesting example:
+
+	CTTY COM2
+
+redirects all *stdout* (screen) and *stdin* (keyboard) I/O to the VT100.  Then click on the VT100 screen to switch focus,
+and you can now interact with the PC via the terminal.  The `CTTY CON` command will restore control to the PC.
+
+More useful scenarios include machines running PC-based debuggers that communicate via a serial port, such as the
+OS/2 kernel debugger, Windows debuggers like `WDEB386`, some versions of `SYMDEB`, and so on.  PC-to-PC configurations will
+also be possible, enabling live demonstrations of classic communication software packages such as `CROSSTALK`.
+
+I've also made it incredibly easy to put machines like this on any PCjs web page.  For this blog post, all I had to do
+was add the following Front Matter to the top of the Markdown file:
+
+	machines:
+	  - id: ibm5170
+	    type: pcx86
+	    connection: com2->vt100.serialPort
+	    config: /devices/pcx86/machine/5170/ega/2048kb/rev3/machine.xml
+	  - id: vt100
+	    type: pc8080
+	    connection: serialPort->ibm5170.com2
+	    config: /devices/pc8080/machine/vt100/machine.xml
+
+and then embed the machines in the post, each with a single line:
+
+	{% raw %}
+	{% include machine.html id="ibm5170" %}
+	{% include machine.html id="vt100" %}
+	{% endraw %}
+
+For people rolling their own web pages, [the basics](/docs/pcx86/) haven't changed, and adding a serial connection merely
+requires adding a *connection* property (eg, `connection:"com2->vt100.serialPort"`) to the *parms* parameter passed to the
+*embedPCx86()* interface.  A similar property (eg, `connection:"serialPort->ibm5170.com2"`) must also be added to the *parms*
+passed to *embedPC8080()*.
+
+For the more adventurous, a [Dual Debugger Configuration](/devices/pcx86/machine/5170/ega/2048kb/rev3/debugger/vt100/)
+is also available.
+
+{% include machine.html id="ibm5170" %}
+
+{% include machine.html id="vt100" %}
+
+*[@jeffpar](http://twitter.com/jeffpar)*  
+*Aug 19, 2016*

index.md

@@ -16,7 +16,7 @@ one of several JavaScript Machines in the [PCjs Project](https://github.com/jeff
 includes:
 
 * [PCx86](/docs/pcx86/), an x86-based IBM PC and PC-compatible emulator
-* [PC8080](/modules/pc8080/), a 8080-based machine emulator (e.g., [Space Invaders](/devices/pc8080/machine/invaders/), [VT100 Terminal](/devices/pc8080/machine/vt100/))
+* [PC8080](/modules/pc8080/), an 8080-based machine emulator (e.g., [Space Invaders](/devices/pc8080/machine/invaders/), [VT100 Terminal](/devices/pc8080/machine/vt100/))
 * [C1Pjs](/docs/c1pjs/), a 6502-based emulation of the Ohio Scientific [Challenger 1P](/devices/c1p/)
 
 All PCjs computer simulations are written entirely in [JavaScript](/modules/).  No Flash, Java or other plugins are

modules/pc8080/lib/serialport.js

@@ -136,6 +136,7 @@ function SerialPort8080(parmsSerial) {
      * Export all functions required by initConnection(); currently, this is the bare minimum, with no flow control.
      */
     this['exports'] = {
+        'connect': this.initConnection,
         'receiveData': this.receiveData
     };
 }
@@ -428,24 +429,33 @@ SerialPort8080.prototype.initBus = function(cmp, bus, cpu, dbg)
  */
 SerialPort8080.prototype.initConnection = function()
 {
-    var sConnection = this.cmp.getMachineParm("connection");
-    if (sConnection) {
-        var asParts = sConnection.split('->');
-        if (asParts.length == 2) {
-            var sSourceID = str.trim(asParts[0]);
-            if (sSourceID != this.idComponent) return;  // this connection string is intended for another instance
-            var sTargetID = str.trim(asParts[1]);
-            this.connection = Component.getComponentByID(sTargetID);
-            if (this.connection) {
-                var exports = this.connection['exports'];
-                if (exports) {
-                    this.sendData = exports['receiveData'];
-                    this.status(this.idMachine + '.' + sSourceID + " connected to " + sTargetID);
-                    return;
+    if (!this.connection) {
+        var sConnection = this.cmp.getMachineParm("connection");
+        if (sConnection) {
+            var asParts = sConnection.split('->');
+            if (asParts.length == 2) {
+                var sSourceID = str.trim(asParts[0]);
+                if (sSourceID != this.idComponent) return;  // this connection string is intended for another instance
+                var sTargetID = str.trim(asParts[1]);
+                this.connection = Component.getComponentByID(sTargetID);
+                if (this.connection) {
+                    var exports = this.connection['exports'];
+                    if (exports) {
+                        var fnConnect = exports['connect'];
+                        if (fnConnect) fnConnect.call(this.connection);
+                        this.sendData = exports['receiveData'];
+                        if (this.sendData) {
+                            this.status(this.idMachine + '.' + sSourceID + " connected to " + sTargetID);
+                            return;
+                        }
+                    }
                 }
             }
+            /*
+             * Changed from notice() to status() because sometimes a connection fails simply because one of us is a laggard.
+             */
+            this.status("Unable to establish connection: " + sConnection);
         }
-        this.notice("Unable to establish connection: " + sConnection);
     }
 };
 

modules/pcx86/lib/serialport.js

@@ -146,6 +146,7 @@ function SerialPort(parmsSerial) {
      * Export all functions required by initConnection(); currently, this is the bare minimum, with no flow control.
      */
     this['exports'] = {
+        'connect': this.initConnection,
         'receiveData': this.receiveData
     };
 }
@@ -489,24 +490,33 @@ SerialPort.prototype.initBus = function(cmp, bus, cpu, dbg)
  */
 SerialPort.prototype.initConnection = function()
 {
-    var sConnection = this.cmp.getMachineParm("connection");
-    if (sConnection) {
-        var asParts = sConnection.split('->');
-        if (asParts.length == 2) {
-            var sSourceID = str.trim(asParts[0]);
-            if (sSourceID != this.idComponent) return;  // this connection string is intended for another instance
-            var sTargetID = str.trim(asParts[1]);
-            this.connection = Component.getComponentByID(sTargetID);
-            if (this.connection) {
-                var exports = this.connection['exports'];
-                if (exports) {
-                    this.sendData = exports['receiveData'];
-                    this.status(this.idMachine + '.' + sSourceID + " connected to " + sTargetID);
-                    return;
+    if (!this.connection) {
+        var sConnection = this.cmp.getMachineParm("connection");
+        if (sConnection) {
+            var asParts = sConnection.split('->');
+            if (asParts.length == 2) {
+                var sSourceID = str.trim(asParts[0]);
+                if (sSourceID != this.idComponent) return;  // this connection string is intended for another instance
+                var sTargetID = str.trim(asParts[1]);
+                this.connection = Component.getComponentByID(sTargetID);
+                if (this.connection) {
+                    var exports = this.connection['exports'];
+                    if (exports) {
+                        var fnConnect = exports['connect'];
+                        if (fnConnect) fnConnect.call(this.connection);
+                        this.sendData = exports['receiveData'];
+                        if (this.sendData) {
+                            this.status(this.idMachine + '.' + sSourceID + " connected to " + sTargetID);
+                            return;
+                        }
+                    }
                 }
             }
+            /*
+             * Changed from notice() to status() because sometimes a connection fails simply because one of us is a laggard.
+             */
+            this.status("Unable to establish connection: " + sConnection);
         }
-        this.notice("Unable to establish connection: " + sConnection);
     }
 };
 

modules/shared/lib/component.js

@@ -226,17 +226,9 @@ Component.subclass = function(subclass, superclass, methods, statics)
  * various resources used by that machine.
  */
 if (window) {
-    if (!window['PCjs']) {
-        window['PCjs'] = {
-            'Machines': {},
-            'Components': []
-        };
-    }
-    /*
-     * Alias the new global objects above to their original property names, to minimize code changes.
-     */
-    Component.machines = window['PCjs']['Machines'];
-    Component.components = window['PCjs']['Components'];
+    if (!window['PCjs']) window['PCjs'] = {};
+    Component.machines = window['PCjs']['Machines'] || (window['PCjs']['Machines'] = {});
+    Component.components = window['PCjs']['Components'] || (window['PCjs']['Components'] = []);
 }
 else {
     /*