diff --git a/app/models/grader_configuration.rb b/app/models/grader_configuration.rb
new file mode 100644
--- /dev/null
+++ b/app/models/grader_configuration.rb
@@ -0,0 +1,176 @@
+require 'yaml'
+
+#
+# This class also contains various login of the system.
+#
+class GraderConfiguration < ActiveRecord::Base
+
+  SYSTEM_MODE_CONF_KEY = 'system.mode'
+  TEST_REQUEST_EARLY_TIMEOUT_KEY = 'contest.test_request.early_timeout'
+  MULTICONTESTS_KEY = 'system.multicontests'
+  CONTEST_TIME_LIMIT_KEY = 'contest.time_limit'
+
+  cattr_accessor :config_cache
+  cattr_accessor :task_grading_info_cache
+  cattr_accessor :contest_time_str
+  cattr_accessor :contest_time
+
+  GraderConfiguration.config_cache = nil
+  GraderConfiguration.task_grading_info_cache = nil
+
+  def self.config_cached?
+    (defined? CONFIGURATION_CACHE_ENABLED) and (CONFIGURATION_CACHE_ENABLED)
+  end
+
+  def self.get(key)
+    if GraderConfiguration.config_cached?
+      if GraderConfiguration.config_cache == nil
+        self.read_config
+      end
+      return GraderConfiguration.config_cache[key]
+    else
+      return GraderConfiguration.read_one_key(key)
+    end
+  end
+
+  def self.[](key)
+    self.get(key)
+  end
+
+  def self.reload
+    self.read_config
+  end
+
+  def self.clear
+    GraderConfiguration.config_cache = nil
+  end
+
+  #
+  # View decision
+  #
+  def self.show_submitbox_to?(user)
+    mode = get(SYSTEM_MODE_CONF_KEY)
+    return false if mode=='analysis'
+    if (mode=='contest') 
+      return false if (user.site!=nil) and 
+        ((user.site.started!=true) or (user.site.finished?))
+    end
+    return true
+  end
+
+  def self.show_tasks_to?(user)
+    if time_limit_mode?
+      return false if not user.contest_started?
+    end
+    return true
+  end
+
+  def self.show_grading_result
+    return (get(SYSTEM_MODE_CONF_KEY)=='analysis')
+  end
+
+  def self.allow_test_request(user)
+    mode = get(SYSTEM_MODE_CONF_KEY)
+    early_timeout = get(TEST_REQUEST_EARLY_TIMEOUT_KEY)
+    if (mode=='contest') 
+      return false if ((user.site!=nil) and 
+        ((user.site.started!=true) or 
+         (early_timeout and (user.site.time_left < 30.minutes))))
+    end
+    return false if mode=='analysis'
+    return true
+  end
+
+  def self.task_grading_info
+    if GraderConfiguration.task_grading_info_cache==nil
+      read_grading_info
+    end
+    return GraderConfiguration.task_grading_info_cache
+  end
+  
+  def self.standard_mode?
+    return get(SYSTEM_MODE_CONF_KEY) == 'standard'
+  end
+
+  def self.contest_mode?
+    return get(SYSTEM_MODE_CONF_KEY) == 'contest'
+  end
+
+  def self.indv_contest_mode?
+    return get(SYSTEM_MODE_CONF_KEY) == 'indv-contest'
+  end
+
+  def self.multicontests?
+    return get(MULTICONTESTS_KEY) == true
+  end
+
+  def self.time_limit_mode?
+    mode = get(SYSTEM_MODE_CONF_KEY)
+    return ((mode == 'contest') or (mode == 'indv-contest')) 
+  end
+  
+  def self.analysis_mode?
+    return get(SYSTEM_MODE_CONF_KEY) == 'analysis'
+  end
+  
+  def self.contest_time_limit
+    contest_time_str = GraderConfiguration[CONTEST_TIME_LIMIT_KEY]
+
+    if not defined? GraderConfiguration.contest_time_str
+      GraderConfiguration.contest_time_str = nil
+    end
+
+    if GraderConfiguration.contest_time_str != contest_time_str
+      GraderConfiguration.contest_time_str = contest_time_str
+      if tmatch = /(\d+):(\d+)/.match(contest_time_str)
+        h = tmatch[1].to_i
+        m = tmatch[2].to_i
+        
+        GraderConfiguration.contest_time = h.hour + m.minute
+      else
+        GraderConfiguration.contest_time = nil
+      end
+    end  
+    return GraderConfiguration.contest_time
+  end
+
+  protected
+
+  def self.convert_type(val,type)
+    case type
+    when 'string'
+      return val
+      
+    when 'integer'
+      return val.to_i
+      
+    when 'boolean'
+      return (val=='true')
+    end
+  end    
+
+  def self.read_config
+    GraderConfiguration.config_cache = {}
+    GraderConfiguration.find(:all).each do |conf|
+      key = conf.key
+      val = conf.value
+      GraderConfiguration.config_cache[key] = GraderConfiguration.convert_type(val,conf.value_type)
+    end
+  end
+
+  def self.read_one_key(key)
+    conf = GraderConfiguration.find_by_key(key)
+    if conf
+      return GraderConfiguration.convert_type(conf.value,conf.value_type)
+    else
+      return nil
+    end
+  end
+
+  def self.read_grading_info
+    f = File.open(TASK_GRADING_INFO_FILENAME)
+    GraderConfiguration.task_grading_info_cache = YAML.load(f)
+    f.close
+  end
+  
+end