Index: test/test_gem_platform.rb
===================================================================
--- test/test_gem_platform.rb	(revision 2463)
+++ test/test_gem_platform.rb	(working copy)
@@ -30,6 +30,9 @@
       'hppa2.0w-hpux11.31'     => ['hppa2.0w',  'hpux',      '11'],
       'java'                   => [nil,         'java',      nil],
       'jruby'                  => [nil,         'java',      nil],
+      'universal-dotnet'       => ['universal', 'dotnet',    nil],
+      'universal-dotnet2.0'    => ['universal', 'dotnet',  '2.0'],
+      'universal-dotnet4.0'    => ['universal', 'dotnet',  '4.0'],
       'powerpc-aix5.3.0.0'     => ['powerpc',   'aix',       '5'],
       'powerpc-darwin7'        => ['powerpc',   'darwin',    '7'],
       'powerpc-darwin8'        => ['powerpc',   'darwin',    '8'],
@@ -227,6 +230,22 @@
     util_set_arch 'java'
     assert_match 'java',  Gem::Platform.local
     assert_match 'jruby', Gem::Platform.local
+      
+    util_set_arch 'universal-dotnet2.0'
+    assert_match 'universal-dotnet',     Gem::Platform.local
+    assert_match 'universal-dotnet-2.0', Gem::Platform.local
+    refute_match 'universal-dotnet-4.0', Gem::Platform.local
+    assert_match 'dotnet',               Gem::Platform.local
+    assert_match 'dotnet-2.0',           Gem::Platform.local
+    refute_match 'dotnet-4.0',           Gem::Platform.local
+    
+    util_set_arch 'universal-dotnet4.0'
+    assert_match 'universal-dotnet',      Gem::Platform.local
+    refute_match 'universal-dotnet-2.0',  Gem::Platform.local  
+    assert_match 'universal-dotnet-4.0',  Gem::Platform.local
+    assert_match 'dotnet',                Gem::Platform.local
+    refute_match 'dotnet-2.0',            Gem::Platform.local  
+    assert_match 'dotnet-4.0',            Gem::Platform.local
 
     util_set_arch 'powerpc-darwin'
     assert_match 'powerpc-darwin', Gem::Platform.local
Index: lib/rubygems/platform.rb
===================================================================
--- lib/rubygems/platform.rb	(revision 2463)
+++ lib/rubygems/platform.rb	(working copy)
@@ -70,6 +70,8 @@
                       when /hpux(\d+)/ then            [ 'hpux',      $1  ]
                       when /^java$/, /^jruby$/ then    [ 'java',      nil ]
                       when /^java([\d.]*)/ then        [ 'java',      $1  ]
+                      when /^dotnet$/ then             [ 'dotnet',    nil ]                       
+                      when /^dotnet([\d.]*)/ then      [ 'dotnet',    $1  ]
                       when /linux/ then                [ 'linux',     $1  ]
                       when /mingw32/ then              [ 'mingw32',   nil ]
                       when /(mswin\d+)(\_(\d+))?/ then
@@ -148,6 +150,7 @@
               when /^i686-darwin(\d)/     then ['x86',       'darwin',  $1    ]
               when /^i\d86-linux/         then ['x86',       'linux',   nil   ]
               when 'java', 'jruby'        then [nil,         'java',    nil   ]
+              when /dotnet(\-(\d+\.\d+))?/ then ['universal','dotnet',  $2    ]
               when /mswin32(\_(\d+))?/    then ['x86',       'mswin32', $2    ]
               when 'powerpc-darwin'       then ['powerpc',   'darwin',  nil   ]
               when /powerpc-darwin(\d)/   then ['powerpc',   'darwin',  $1    ]