diff --git a/docs/manual/CoreTasks/conditions.html b/docs/manual/CoreTasks/conditions.html
index 6c1091050..ac66f63cc 100644
--- a/docs/manual/CoreTasks/conditions.html
+++ b/docs/manual/CoreTasks/conditions.html
@@ -113,7 +113,9 @@ the tests succeed.
   <li>netware (for Novell NetWare)</li>
   <li>os/2 (for OS/2)</li>
   <li>tandem (for HP's NonStop Kernel - formerly Tandem)</li>
-  <li>win9x for Microsoft Windows 95 and 98</li>
+  <li>win9x for Microsoft Windows 95 and 98, ME and CE</li>
+  <li>nt for Microsoft Windows NT-based systems, including Windows 2000, XP and
+      successors</li>
   <li>z/os for z/OS and OS/390</li>
   <li>os/400 for OS/400</li>
   <li>openvms for OpenVMS</li>
diff --git a/src/main/org/apache/tools/ant/taskdefs/Chmod.java b/src/main/org/apache/tools/ant/taskdefs/Chmod.java
index c00cd5535..0b04f6e1d 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Chmod.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Chmod.java
@@ -250,6 +250,6 @@ public class Chmod extends ExecuteOn {
      * @return true if the os is valid.
      */
     protected boolean isValidOs() {
-        return Os.isFamily("unix") && super.isValidOs();
+        return Os.isFamily(Os.FAMILY_UNIX) && super.isValidOs();
     }
 }
diff --git a/src/main/org/apache/tools/ant/taskdefs/condition/Os.java b/src/main/org/apache/tools/ant/taskdefs/condition/Os.java
index a23666c78..de3fa67c8 100644
--- a/src/main/org/apache/tools/ant/taskdefs/condition/Os.java
+++ b/src/main/org/apache/tools/ant/taskdefs/condition/Os.java
@@ -36,10 +36,68 @@ public class Os implements Condition {
     private static final String PATH_SEP =
         System.getProperty("path.separator");
 
+    /**
+     * OS family to look for
+     */
     private String family;
+    /**
+     * Name of OS
+     */
     private String name;
+    /**
+     * version of OS
+     */
     private String version;
+    /**
+     * OS architecture
+     */
     private String arch;
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_WINDOWS = "windows";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_9X = "win9x";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_NT = "nt";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_OS2 = "os/2";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_NETWARE = "netware";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_DOS = "dos";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_MAC = "mac";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_TANDEM = "tandem";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_UNIX = "unix";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_VMS = "openvms";
+    /**
+     * OS family that can be tested for. {@value}
+     */
+    public static final String FAMILY_ZOS = "z/os";
+    /** OS family that can be tested for. {@value} */
+    public static final String FAMILY_OS400 = "os/400";
 
     /**
      * Default constructor
@@ -186,35 +244,49 @@ public class Os implements Condition {
             boolean isVersion = true;
 
             if (family != null) {
-                if (family.equals("windows")) {
-                    isFamily = OS_NAME.indexOf("windows") > -1;
-                } else if (family.equals("os/2")) {
-                    isFamily = OS_NAME.indexOf("os/2") > -1;
-                } else if (family.equals("netware")) {
-                    isFamily = OS_NAME.indexOf("netware") > -1;
-                } else if (family.equals("dos")) {
-                    isFamily = PATH_SEP.equals(";") && !isFamily("netware");
-                } else if (family.equals("mac")) {
-                    isFamily = OS_NAME.indexOf("mac") > -1;
-                } else if (family.equals("tandem")) {
-                    isFamily = OS_NAME.indexOf("nonstop_kernel") > -1;
-                } else if (family.equals("unix")) {
-                    isFamily = PATH_SEP.equals(":")
-                        && !isFamily("openvms")
-                        && (!isFamily("mac") || OS_NAME.endsWith("x"));
-                } else if (family.equals("win9x")) {
-                    isFamily = isFamily("windows")
-                        && (OS_NAME.indexOf("95") >= 0
+
+                //windows probing logic relies on the word 'windows' in
+                //the OS
+                boolean isWindows = OS_NAME.indexOf(FAMILY_WINDOWS) > -1;
+                boolean is9x = false;
+                boolean isNT = false;
+                if(isWindows) {
+                    //there are only four 9x platforms that we look for
+                    is9x = (OS_NAME.indexOf("95") >= 0
                             || OS_NAME.indexOf("98") >= 0
                             || OS_NAME.indexOf("me") >= 0
+                            //wince isn't really 9x, but crippled enough to
+                            //be a muchness. Ant doesnt run on CE, anyway.
                             || OS_NAME.indexOf("ce") >= 0);
-                } else if (family.equals("z/os")) {
-                    isFamily = OS_NAME.indexOf("z/os") > -1
+                    isNT = !is9x;
+                }
+                if (family.equals(FAMILY_WINDOWS)) {
+                    isFamily = isWindows;
+                } else if (family.equals(FAMILY_9X)) {
+                    isFamily = isWindows && is9x;
+                } else if (family.equals(FAMILY_NT)) {
+                    isFamily = isWindows && isNT;
+                } else if (family.equals(FAMILY_OS2)) {
+                    isFamily = OS_NAME.indexOf(FAMILY_OS2) > -1;
+                } else if (family.equals(FAMILY_NETWARE)) {
+                    isFamily = OS_NAME.indexOf(FAMILY_NETWARE) > -1;
+                } else if (family.equals(FAMILY_DOS)) {
+                    isFamily = PATH_SEP.equals(";") && !isFamily(FAMILY_NETWARE);
+                } else if (family.equals(FAMILY_MAC)) {
+                    isFamily = OS_NAME.indexOf(FAMILY_MAC) > -1;
+                } else if (family.equals(FAMILY_TANDEM)) {
+                    isFamily = OS_NAME.indexOf("nonstop_kernel") > -1;
+                } else if (family.equals(FAMILY_UNIX)) {
+                    isFamily = PATH_SEP.equals(":")
+                        && !isFamily(FAMILY_VMS)
+                        && (!isFamily(FAMILY_MAC) || OS_NAME.endsWith("x"));
+                } else if (family.equals(FAMILY_ZOS)) {
+                    isFamily = OS_NAME.indexOf(FAMILY_ZOS) > -1
                         || OS_NAME.indexOf("os/390") > -1;
-                } else if (family.equals("os/400")) {
-                    isFamily = OS_NAME.indexOf("os/400") > -1;
-                } else if (family.equals("openvms")) {
-                    isFamily = OS_NAME.indexOf("openvms") > -1;
+                } else if (family.equals(FAMILY_OS400)) {
+                    isFamily = OS_NAME.indexOf(FAMILY_OS400) > -1;
+                } else if (family.equals(FAMILY_VMS)) {
+                    isFamily = OS_NAME.indexOf(FAMILY_VMS) > -1;
                 } else {
                     throw new BuildException(
                         "Don\'t know how to detect os family \""