diff --git a/app/controllers/graders_controller.rb b/app/controllers/graders_controller.rb
--- a/app/controllers/graders_controller.rb
+++ b/app/controllers/graders_controller.rb
@@ -61,4 +61,22 @@
     @submission = Submission.find(params[:id])
   end
 
+  # various grader controls
+
+  def stop 
+    grader_proc = GraderProcess.find(params[:id])
+    stop_grader(grader_proc.pid)
+    redirect_to :action => 'list'
+  end
+
+
+  protected
+
+  def stop_grader(pid)
+    if GraderProcess.grader_control_enabled?
+      cmd = "#{GRADER_SCRIPT_DIR}/grader stop #{pid}"
+      system(cmd)
+    end
+  end
+
 end
diff --git a/app/models/grader_process.rb b/app/models/grader_process.rb
--- a/app/models/grader_process.rb
+++ b/app/models/grader_process.rb
@@ -43,6 +43,14 @@
                                        Time.now.gmtime - GraderProcess.stalled_time])
   end
   
+  def self.grader_control_enabled?
+    if defined? GRADER_SCRIPT_DIR
+      GRADER_SCRIPT_DIR != ''
+    else
+      false
+    end
+  end
+
   def report_active(task=nil)
     self.active = true
     if task!=nil
diff --git a/app/views/graders/_grader_list.html.haml b/app/views/graders/_grader_list.html.haml
--- a/app/views/graders/_grader_list.html.haml
+++ b/app/views/graders/_grader_list.html.haml
@@ -15,7 +15,8 @@
       %tr{:class => c}        
         = render :partial => 'grader', :locals => {:grader => grader}
         - if not grader.terminated
-          %td= link_to 'stop', {:action => 'stop', :id => grader}
+          - if GraderProcess.grader_control_enabled?
+            %td= link_to 'stop', {:action => 'stop', :id => grader}
         - else
           %td= link_to 'clear', {:action => 'clear', :id => grader}
 - else
diff --git a/app/views/graders/list.html.haml b/app/views/graders/list.html.haml
--- a/app/views/graders/list.html.haml
+++ b/app/views/graders/list.html.haml
@@ -1,6 +1,6 @@
 - content_for :head do
   = stylesheet_link_tag 'graders'
-  <meta http-equiv ="refresh" content="10"/>
+  <meta http-equiv ="refresh" content="60"/>
 
 %h1 Grader information
 
diff --git a/config/environment.rb.SAMPLE b/config/environment.rb.SAMPLE
--- a/config/environment.rb.SAMPLE
+++ b/config/environment.rb.SAMPLE
@@ -73,6 +73,10 @@
 
 # Include your application configuration below
 
+# If you want to manage graders through web interface, set the path to
+# script directory below
+GRADER_SCRIPT_DIR = ''
+
 # These are where inputs and outputs of test requests are stored
 TEST_REQUEST_INPUT_FILE_DIR = RAILS_ROOT + '/data/test_request/input'
 TEST_REQUEST_OUTPUT_FILE_DIR = RAILS_ROOT + '/data/test_request/output'