diff --git a/js/dos/io.js b/js/dos/io.js
new file mode 100644
index 0000000..f6921b2
--- /dev/null
+++ b/js/dos/io.js
@@ -0,0 +1,432 @@
+/**
+ * Created by sbosse on 3/28/15.
+ *
+ * This module encapsulates all IO operations (except networking) supporting
+ * node.js and browser applications.
+ */
+
+
+if (!(process.env.NODE_ENV === 'browser')) {
+    /*
+     ************
+     ** Node.js
+     ************
+     */
+    var util = require('util');
+    var GetEnv = require('getenv');
+    var Fs = require('fs');
+
+    var stderr_fun = function (str) { process.stderr.write(str); };
+    var stdout_fun = function (str) { process.stdout.write(str); };
+
+    /*
+     ** node.js specific
+     */
+
+    var tracefile = undefined;
+    var tracing = true;
+
+    /*
+     ** node.js
+     */
+    module.exports = {
+        /**************
+         ** FILE IO
+         ***************/
+        close: function (fd) {
+            Fs.closeSync(fd);
+        },
+        exists: function (path) {
+            return Fs.existsSync(path);
+        },
+        open: function (path, mode) {
+            return Fs.openSync(path, mode);
+        },
+
+        read: function (fd, len, foff) {
+            // TODO
+        },
+        /**
+         *
+         * @param path
+         * @returns {string|undefined}
+         */
+        read_file: function (path) {
+            try {
+                return Fs.readFileSync(path);
+            } catch (e) {
+                return undefined;
+            }
+        },
+
+        read_line: function (fd) {
+            // TODO
+        },
+        /**
+         *
+         * @param fd
+         * @param buf
+         * @param boff
+         * @param len
+         * @param [foff]
+         * @returns {*}
+         */
+        read_buf: function (fd, buf, boff, len, foff) {
+            return Fs.readSync(fd, buf, boff, len, foff);
+        },
+        sync: function (fd) {
+            Fs.fsyncSync(fd);
+        },
+        /**
+         *
+         * @param fd
+         * @param data
+         * @param [foff]
+         * @returns {number}
+         */
+        write: function (fd, data, foff) {
+            return Fs.writeSync(fd, data, foff);
+        },
+        /**
+         *
+         * @param fd
+         * @param buf
+         * @param bpos
+         * @param blen
+         * @param [foff]
+         * @returns {number}
+         */
+        write_buf: function (fd, buf, bpos, blen, foff) {
+            return Fs.writeSync(fd, buf, bpos, blen, foff);
+        },
+        /**
+         *
+         * @param path
+         * @param {string} buf
+         */
+        write_file: function (path,buf) {
+            try {
+                Fs.writeFileSync(path, buf, 'binary');
+                return buf.length;
+            } catch (e) {
+                return -1;
+            }
+        },
+
+        /****************
+         ** CONSOLE IO
+         ****************/
+        debug: function (msg) {
+            console.error('Debug: ' + msg);
+        },
+        err: function (msg) {
+            console.error('Error: ' + msg);
+            throw Error(msg);
+        },
+        fail: function (msg) {
+            console.error('Fatal Error: ' + msg);
+            process.exit(0);
+        },
+        inspect: function (obj) {
+            console.warn(util.inspect(obj))
+        },
+        stacktrace: function () {
+            var e = new Error('dummy');
+            var stack = e.stack.replace(/^[^\(]+?[\n$]/gm, '')
+                .replace(/^\s+at\s+/gm, '')
+                .replace(/^Object.<anonymous>\s*\(/gm, '{anonymous}()@')
+                .split('\n');
+            this.out('Stack Trace');
+            this.out('--------------------------------');
+            for(var i in stack) {
+                if (i>0) {
+                    var line = stack[i];
+                    if(line.indexOf('Module.',0)>=0) break;
+                    this.out(line);
+                }
+            }
+            this.out('--------------------------------');
+        },
+        /**
+         *
+         * @param e
+         * @param where
+         */
+        printstack: function (e,where) {
+            var stack = e.stack //.replace(/^[^\(]+?[\n$]/gm, '')
+                .replace(/^\s+at\s+/gm, '')
+                .replace(/^Object.<anonymous>\s*\(/gm, '{anonymous}()@')
+                .split('\n');
+            if (where==undefined) this.out(e);
+            else this.out(where+': '+e);
+            this.out('Stack Trace');
+            this.out('--------------------------------');
+            for(var i in stack) {
+                if (i>0) {
+                    var line = stack[i];
+                    if(line.indexOf('Module.',0)>=0) break;
+                    this.out(line);
+                }
+            }
+            this.out('--------------------------------');
+        },
+        /**
+         *
+         * @param {boolean|string} condmsg conditional message var log=X;  log((log lt. N)||(msg))
+         */
+        log: function (condmsg) {
+            if (condmsg != true) console.warn(condmsg);
+        },
+        out: function (msg) {
+            console.warn(msg)
+        },
+        warn: function (msg) {
+            console.warn('Warning: ' + msg);
+        },
+
+        set_stderr: function(fun) {
+            stderr_fun=fun;
+        },
+        set_stdout: function(fun) {
+            stdout_fun=fun;
+        },
+
+        stderr: function (msg) {
+            stderr_fun(msg);
+        },
+        stdout: function (msg) {
+            stdout_fun(msg);
+        },
+
+        /** Write a message with a time stamp written to the trace file.
+         *
+         * @param {boolean|string} condmsg conditional message var trace=Io.tracing;  trace(trace||(msg))
+         */
+        trace: function (condmsg) {
+            if (condmsg != true && tracefile != undefined) {
+                var date = new Date();
+                var time = date.getTime();
+                Fs.writeSync(tracefile, '[' + time + '] ' + condmsg + '\n');
+            }
+        },
+        tracing: tracing,
+        /**
+         *
+         * @param {string} path
+         */
+        trace_open: function (path) {
+            tracefile = Fs.openSync(path, 'w+');
+            if (tracefile != undefined) this.tracing = false;
+        },
+
+        /**************
+         ** Process control
+         ***************/
+        exit: function (n) {
+            process.exit(n);
+        },
+        /****************************
+         ** Environment and Arguments
+         ****************************/
+        getenv: function (name, def) {
+            return GetEnv(name, def);
+        },
+        workdir: function () {
+            return this.getenv('PWD','');
+        },
+
+        /**
+         *  @return {string []}
+         */
+        getargs: function () {
+            return process.argv;
+        }
+    };
+} else {
+    /*
+    ************
+    ** Browser
+    ************
+    */
+
+    var tracing = true;
+    var stderr_fun = function (str) { console.log(str); };
+    var stdout_fun = function (str) { console.log(str); };
+    var args=[];
+
+    module.exports = {
+        /*
+         ** FILE IO
+         * TODO WebStorage
+         */
+        close: function (fd) {
+            return;
+        },
+        exists: function (path) {
+            return false;
+        },
+        open: function (path, mode) {
+            var fd = Fs.openSync(path, mode);
+            return fd;
+        },
+
+        read: function (fd, len, foff) {
+            // TODO
+        },
+        read_file: function (path) {
+            return '';
+        },
+
+        read_line: function (fd) {
+            // TODO
+        },
+        /**
+         *
+         * @param fd
+         * @param buf
+         * @param boff
+         * @param len
+         * @param [foff]
+         * @returns {*}
+         */
+        read_buf: function (fd, buf, boff, len, foff) {
+            return -1;
+        },
+        sync: function (fd) {
+            return;
+        },
+        /**
+         *
+         * @param fd
+         * @param data
+         * @param [foff]
+         * @returns {*}
+         */
+        write: function (fd, data, foff) {
+            return -1;
+        },
+        /**
+         *
+         * @param fd
+         * @param buf
+         * @param bpos
+         * @param blen
+         * @param [foff]
+         * @returns {*}
+         */
+        write_buf: function (fd, buf, bpos, blen, foff) {
+            return -1;
+        },
+
+        /*
+         ** CONSOLE IO
+         */
+        debug: function (msg) {
+            stderr_fun('Debug: ' + msg);
+        },
+        err: function (msg) {
+            stderr_fun('Error: ' + msg);
+            throw Error(msg);
+        },
+        fail: function (msg) {
+            stderr_fun('Fatal Error: ' + msg);
+        },
+        inspect: function (obj) {
+            return;
+        },
+        stacktrace: function () {
+            var e = new Error('dummy');
+            var stack = e.stack.replace(/^[^\(]+?[\n$]/gm, '')
+                .replace(/^\s+at\s+/gm, '')
+                .replace(/^Object.<anonymous>\s*\(/gm, '{anonymous}()@')
+                .split('\n');
+            stderr_fun('Stack Trace');
+            stderr_fun('--------------------------------');
+            for(var i in stack) {
+                if (i>0) {
+                    var line = stack[i];
+                    if(line.indexOf('Module.',0)>=0) break;
+                    stderr_fun(line);
+                }
+            }
+            stderr_fun('--------------------------------');
+        },
+        /**
+         *
+         * @param e
+         * @param where
+         */
+        printstack: function (e,where) {
+            if (where==undefined) stderr_fun(e);
+            else stderr_fun(where+': '+e);
+        },
+        /**
+         *
+         * @param {boolean|string} condmsg conditional message var log=X;  log((log lt. N)||(msg))
+         */
+        log: function (condmsg) {
+            if (condmsg != true) console.warn(condmsg);
+        },
+        out: function (msg) {
+            stdout_fun(msg)
+        },
+        warn: function (msg) {
+            stderr_fun('Warning: ' + msg);
+        },
+
+
+        set_stderr: function(fun) {
+            stderr_fun=fun;
+        },
+        set_stdout: function(fun) {
+            stdout_fun=fun;
+        },
+
+        stderr: function (msg) {
+            stderr_fun(msg);
+        },
+        stdout: function (msg) {
+            stdout_fun(msg);
+        },
+
+        /** Write a message with a time stamp written to the trace file.
+         *
+         * @param {boolean|string} condmsg conditional message var trace=Io.tracing;  trace(trace||(msg))
+         */
+        trace: function (condmsg) {
+            if (condmsg != true && tracefile != undefined) {
+                var date = new Date();
+                var time = date.getTime();
+                this.log('[' + time + '] ' + condmsg + '\n');
+            }
+        },
+        tracing: tracing,
+        /**
+         *
+         * @param {string} path
+         */
+        trace_open: function (path) {
+            return undefined;
+        },
+
+        exit: function (n) {
+            return;
+        },
+        getenv: function (name, def) {
+            return def;
+        },
+        workdir: function () {
+            return '';
+        },
+        /**
+         *  @return {string []}
+         */
+        getargs: function () {
+            return args;
+        },
+        set_args: function (argv) {
+            args=argv;
+        }
+    };
+
+}
\ No newline at end of file