diff --git a/app/models/grader_message.rb b/app/models/grader_message.rb
deleted file mode 100644
--- a/app/models/grader_message.rb
+++ /dev/null
@@ -1,90 +0,0 @@
-class GraderMessage < ActiveRecord::Base
-
-  belongs_to :taken_grader_process, :class_name => :grader_process
-
-  GRADE_SUBMISSION = 1
-  GRADE_TEST_REQUEST = 2
-  STOP = 3
-
-  RECIPIENT_ANY = -1
-
-  def self.create_message(recipient, command, options=nil, target_id=nil)
-    recipient_id = recipient
-    if recipient == :any
-      recipient_id = GraderMessage::RECIPIENT_ANY
-    end
-    
-    GraderMessage.create(:grader_process_id => recipient_id,
-                         :command => command,
-                         :options => options,
-                         :target_id => target_id,
-                         :taken => false)
-  end
-
-  def self.create_grade_submission(submission, 
-                                   grading_environment="grading")
-    GraderMessage.create_message(:any,
-                                 GraderMessage::GRADE_SUBMISSION,
-                                 grading_environment,
-                                 submission.id)
-  end
-  
-  def self.create_grade_test_request(test_request, 
-                                     grading_environment="grading")
-    GraderMessage.create_message(:any,
-                                 GraderMessage::GRADE_TEST_REQUEST,
-                                 grading_environment,
-                                 test_request.id)
-  end
-  
-  def self.create_stop(grader_process_id)
-    GraderMessage.create_message(grader_process_id,
-                                 GraderMessage::STOP)
-  end
-
-  def self.get_message_for(recipient_id, accepting_commands=:all)
-    command_conditions = 
-      GraderMessage.build_command_conditions(accepting_commands)
-    recp_conditions= "((`grader_process_id` = #{recipient_id.to_i})" +
-      " OR (`grader_process_id` = #{GraderMessage::RECIPIENT_ANY}))"
-
-    message = nil   # need this to bind message in do-block for transaction
-    begin
-      GraderMessage.transaction do
-        message = GraderMessage.find(:first, 
-                                     :order => "created_at", 
-                                     :conditions => 
-                                     "(`taken` = 0)" + 
-                                     " AND (#{recp_conditions})" + 
-                                     " AND (#{command_conditions})",
-                                     :lock => true)
-        if message!=nil
-          message.taken = true
-          message.taken_grader_process_id = recipient_id
-          message.save!
-        end
-      end
-      
-    rescue
-      message = nil
-
-    end
-    
-    message
-  end
-  
-  protected
-  
-  def self.build_command_conditions(accepting_commands)
-    if accepting_commands==:all
-      return '(1=1)'
-    else
-      conds = []
-      accepting_commands.each do |command|
-        conds << "(`command` = #{command.to_i})"
-      end
-      return "(" + conds.join(" OR ") + ")"
-    end
-  end
-  
-end
diff --git a/db/migrate/20090429014554_create_grader_messages.rb b/db/migrate/20090429014554_create_grader_messages.rb
deleted file mode 100644
--- a/db/migrate/20090429014554_create_grader_messages.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-class CreateGraderMessages < ActiveRecord::Migration
-  def self.up
-    create_table :grader_messages do |t|
-      t.integer :grader_process_id
-      t.integer :command
-      t.string :options
-      t.integer :target_id
-      t.boolean :taken
-      t.integer :taken_grader_process_id
-      t.timestamps
-    end
-  end
-
-  def self.down
-    drop_table :grader_messages
-  end
-end
diff --git a/db/schema.rb b/db/schema.rb
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -9,7 +9,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20090429014554) do
+ActiveRecord::Schema.define(:version => 20090426131044) do
 
   create_table "announcements", :force => true do |t|
     t.string   "author"
@@ -42,17 +42,6 @@
     t.datetime "updated_at"
   end
 
-  create_table "grader_messages", :force => true do |t|
-    t.integer  "grader_process_id"
-    t.integer  "command"
-    t.string   "options"
-    t.integer  "target_id"
-    t.boolean  "taken"
-    t.integer  "taken_grader_process_id"
-    t.datetime "created_at"
-    t.datetime "updated_at"
-  end
-
   create_table "grader_processes", :force => true do |t|
     t.string   "host",       :limit => 20
     t.integer  "pid"
diff --git a/judge/scripts/config/.gitignore b/judge/scripts/config/.gitignore
--- a/judge/scripts/config/.gitignore
+++ b/judge/scripts/config/.gitignore
@@ -1,2 +1,2 @@
-env_*.rb
+env*.rb
 
diff --git a/judge/scripts/config/environment.rb b/judge/scripts/config/environment.rb
deleted file mode 100644
--- a/judge/scripts/config/environment.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-# Rails app directory
-RAILS_ROOT = File.expand_path(File.join(File.dirname(__FILE__),"../../.."))
-GRADER_ROOT = File.expand_path(File.join(File.dirname(__FILE__),".."))
-
-# This load all required codes
-require File.join(File.dirname(__FILE__),'../lib/boot')
-
-# load the required environment file
-require File.dirname(__FILE__) + "/env_#{GRADER_ENV}.rb"
diff --git a/judge/scripts/config/environment.rb.SAMPLE b/judge/scripts/config/environment.rb.SAMPLE
new file mode 100644
--- /dev/null
+++ b/judge/scripts/config/environment.rb.SAMPLE
@@ -0,0 +1,10 @@
+# Rails app directory
+RAILS_ROOT = "/home/jittat/web_grader"
+
+GRADER_ROOT = "/home/jittat/grader/scripts"
+
+# This load all required codes
+require File.join(File.dirname(__FILE__),'../lib/boot')
+
+# load the required environment file
+require File.dirname(__FILE__) + "/env_#{GRADER_ENV}.rb"
diff --git a/judge/scripts/grader b/judge/scripts/grader
--- a/judge/scripts/grader
+++ b/judge/scripts/grader
@@ -28,7 +28,7 @@
     raise "Log directory does not exist: #{config.log_dir}"
   end
   config.log_dir + 
-    "/#{GRADER_ENV}.#{Process.pid}"
+    "/#{GRADER_ENV}_#{config.grader_mode}.#{Process.pid}"
 end
 
 def log(str)
diff --git a/judge/scripts/grader-batch b/judge/scripts/grader-batch
deleted file mode 100755
--- a/judge/scripts/grader-batch
+++ /dev/null
@@ -1,135 +0,0 @@
-#!/usr/bin/ruby
-
-require 'optparse'
-
-def config
-  Grader::Configuration.get_instance
-end
-
-def log_file_name
-  if !File.exists?(config.log_dir)
-    raise "Log directory does not exist: #{config.log_dir}"
-  end
-  config.log_dir + 
-    "/#{GRADER_ENV}.#{Process.pid}"
-end
-
-def log(str)
-  if config.talkative
-    puts str
-  end
-  if config.logging
-    fp = File.open(log_file_name,"a")
-    fp.puts("GRADER: #{Time.new.strftime("%H:%M")} #{str}")
-    fp.close
-  end
-end
-
-def parse_arguments(args)
-  options = {
-    :environment => 'grading',
-    :problems => [],
-    :submissions => []
-  }
-  opts = OptionParser.new do |opts|
-    opts.banner = <<BANNER
-grader-batch - the grader for batch grading..
-Usage: grader-batch [options]
-BANNER
-
-    opts.on("-e", "--env", "Set environment: grading (*), exam, etc.") do |env|
-      options[:environment] = env
-    end
-
-    opts.on("--prob p1,p2,p3", Array, "Grade problems p1, p2, and p3.") do |prob_list|
-      options[:problems] += prob_list
-    end
-    
-    opts.on("--sub s1,s2,s3", Array, "Grade submissions specified by ids") do |submission_list|
-      options[:submissions] += submission_list
-    end
-    
-    # help
-    opts.on_tail("-h", "--help", "Show this message") do
-      puts opts
-      exit
-    end
-  end
-
-  opts.parse!
-  return options
-end
-
-
-#########################################
-# main program
-#########################################
-
-options = parse_arguments(ARGV)
-
-# reading environment and options
-GRADER_ENV = options[:environment]
-puts "environment: #{GRADER_ENV}"
-require File.join(File.dirname(__FILE__),'config/environment')
-
-# reading rails environment
-log 'Reading rails environment'
-
-RAILS_ENV = config.rails_env
-require RAILS_ROOT + '/config/environment'
-
-# register grader process
-if config.report_grader
-  grader_proc = GraderProcess.register(config.grader_hostname,
-                                       Process.pid,
-                                       GRADER_ENV)
-else
-  grader_proc = nil
-end
-
-#set loggin environment
-ENV['GRADER_LOGGING'] = log_file_name
-
-# register exit handler to report inactive, and terminated
-at_exit do
-  if grader_proc!=nil
-    grader_proc.report_inactive 
-    grader_proc.terminate
-  end
-end
-
-# grading
-
-engine = Grader::Engine.new
-runner = Grader::Runner.new(engine, grader_proc)
-
-# grade problems
-options[:problems].each do |prob_name|
-  grader_proc.report_active if grader_proc!=nil
-  prob = Problem.find_by_name(prob_name)
-  if prob==nil
-    puts "cannot find problem: #{prob_name}"
-  else
-    runner.grade_problem(prob)
-  end
-  grader_proc.report_inactive if grader_proc!=nil
-end
-
-# grade submissions
-options[:submissions].each do |sub_id|
-  grader_proc.report_active if grader_proc!=nil
-  puts "Grading #{sub_id}"
-  begin
-    submission = Submission.find(sub_id.to_i)
-  rescue ActiveRecord::RecordNotFound
-    puts "Record not found"
-    submission = nil
-  end
-
-  if submission!=nil
-    runner.grade_submission(submission)
-  end
-  grader_proc.report_inactive if grader_proc!=nil
-end
-
-puts "Done."
diff --git a/judge/scripts/lib/engine.rb b/judge/scripts/lib/engine.rb
--- a/judge/scripts/lib/engine.rb
+++ b/judge/scripts/lib/engine.rb
@@ -71,7 +71,7 @@
           copy_log = copy_script(problem_home)
           save_copy_log(problem_home,copy_log)
         end
-
+      
         call_judge(problem_home,language,grading_dir,source_name)
 
         @reporter.report(submission,"#{grading_dir}/test-result")
@@ -102,7 +102,7 @@
     def call_judge(problem_home,language,grading_dir,fname)
       ENV['PROBLEM_HOME'] = problem_home
       
-      talk "Grading in #{grading_dir}"
+      talk grading_dir
       Dir.chdir grading_dir
       cmd = "#{problem_home}/script/judge #{language} #{fname}"
       talk "CMD: #{cmd}"
diff --git a/spec/models/grader_message_spec.rb b/spec/models/grader_message_spec.rb
deleted file mode 100644
--- a/spec/models/grader_message_spec.rb
+++ /dev/null
@@ -1,119 +0,0 @@
-
-require File.dirname(__FILE__) + '/../spec_helper'
-
-describe GraderMessage do
-
-  def add_submission_with_id(id)
-    submission = stub(Submission, :id => id)
-    GraderMessage.create_grade_submission("exam",submission)
-  end
-
-  before(:each) do 
-    GraderMessage.destroy_all
-  end
-
-  it "should return nil when there is no messages to me" do
-    GraderMessage.create_message(1,0)
-    GraderMessage.get_message_for(2).should == nil
-  end
-  
-  it "should return a messages directed to me" do
-    GraderMessage.create_message(1,0)
-    GraderMessage.get_message_for(2).should == nil
-  end
-  
-  it "should return a messages directed to me, in order of creation" do
-    msg1 = GraderMessage.create_message(1,0)
-    msg2 = GraderMessage.create_message(2,2)
-    msg3 = GraderMessage.create_message(1,2)
-    GraderMessage.get_message_for(1).id.should == msg1.id
-    GraderMessage.get_message_for(1).id.should == msg3.id
-  end
-  
-  it "should not return a messages directed to me if the command is not on my list of accepting commands" do
-    msg1 = GraderMessage.create_message(1,GraderMessage::GRADE_SUBMISSION)
-    msg2 = GraderMessage.create_message(1,GraderMessage::STOP)
-    GraderMessage.get_message_for(1,[GraderMessage::GRADE_TEST_REQUEST]).should == nil
-  end
-  
-  it "should return a messages directed to me if the command is on my list of accepting commands" do
-    msg1 = GraderMessage.create_message(1,0)
-    msg2 = GraderMessage.create_message(1,2)
-    msg3 = GraderMessage.create_message(2,2) 
-    GraderMessage.get_message_for(1,[2]).id.should == msg2.id
-    GraderMessage.get_message_for(1,[2]).should == nil
-  end
-  
-  it "should return a message directed to anyone when I'm requesting" do
-    msg1 = GraderMessage.create_message(:any,0)
-    GraderMessage.get_message_for(1).id.should == msg1.id
-  end
-
-  it "should return a messages directed to anyone only if the command is on my list of accepting commands" do
-    msg1 = GraderMessage.create_message(:any,0)
-    GraderMessage.get_message_for(1,[1]).should == nil
-    msg2 = GraderMessage.create_message(:any,1)
-    GraderMessage.get_message_for(1,[1]).id.should == msg2.id
-  end
-
-  it "should return messages directed to anyone to many graders in order of requests" do
-    msg1 = GraderMessage.create_message(:any,0)
-    msg2 = GraderMessage.create_message(:any,2)
-    msg3 = GraderMessage.create_message(:any,2) 
-    GraderMessage.get_message_for(1).id.should == msg1.id
-    GraderMessage.get_message_for(2).id.should == msg2.id
-    GraderMessage.get_message_for(1).id.should == msg3.id
-  end
-  
-  it "should return messages directed to anyone to graders accepting those commands in order of requests" do
-    msg1 = GraderMessage.create_message(:any,0)
-    msg2 = GraderMessage.create_message(:any,1)
-    msg3 = GraderMessage.create_message(:any,2) 
-    msg4 = GraderMessage.create_message(:any,2) 
-    msg5 = GraderMessage.create_message(:any,3) 
-    GraderMessage.get_message_for(1).id.should == msg1.id
-    GraderMessage.get_message_for(2,[2]).id.should == msg3.id
-    GraderMessage.get_message_for(1,[3]).id.should == msg5.id
-    GraderMessage.get_message_for(2).id.should == msg2.id
-    GraderMessage.get_message_for(1).id.should == msg4.id
- end
-
-  it "should get all messages dispatched when there are many concurrent processes" do
-    n = 100
-    msg = []
-    n.times do |i|
-      msg << GraderMessage.create_message(:any,i)
-    end
-
-    #puts "#{n} messages created"
-
-    t = 10  # use 10 threads
-    ths = []
-    t.times do |i|
-      fork do
-        #puts "I'm the #{i+1}-th process."
-        begin
-          m = GraderMessage.get_message_for(i)
-          #puts "#{i+1} got #{m.id}" if m
-          sleep 0.1
-        end while m!=nil
-        #puts "The #{i+1}-th process terminated."
-        exit 0
-      end
-    end
-
-    t.times do
-      Process.wait
-    end
-
-    # for some reason the connection is lost at this point.
-    GraderMessage.connection.reconnect!
-
-    # check that all messages have been processed
-    GraderMessage.find(:all) do |msg|
-      msg.taken_grader_process.should != nil
-    end
-
-  end
-  
-end
diff --git a/test/fixtures/grader_messages.yml b/test/fixtures/grader_messages.yml
deleted file mode 100644
--- a/test/fixtures/grader_messages.yml
+++ /dev/null
@@ -1,7 +0,0 @@
-# Read about fixtures at http://ar.rubyonrails.org/classes/Fixtures.html
-
-# one:
-#   column: value
-#
-# two:
-#   column: value
diff --git a/test/unit/grader_message_test.rb b/test/unit/grader_message_test.rb
deleted file mode 100644
--- a/test/unit/grader_message_test.rb
+++ /dev/null
@@ -1,8 +0,0 @@
-require 'test_helper'
-
-class GraderMessageTest < ActiveSupport::TestCase
-  # Replace this with your real tests.
-  test "the truth" do
-    assert true
-  end
-end