anchor.diff:  %@private
   init(_Args) ->
       ets:new(?MODULE, [set, protected, named_table]),
  +    process_flag(trap_exit, true),
       State = null,
       State.
   
  
positive.code: 
  %% gen_server callbacks
  -export([init/1,on/2,
      
  	 register_process/3, 
  	 lookup_process/2,
  	 lookup_process/1,
  	 find_cs_node/0, 
  	 find_all_cs_nodes/0, 
  	 find_all_processes/1, 
  	 find_group/1,
           find_all_groups/1,
  
  	 get_groups/0,
  	 get_processes_in_group/1, 
  	 %get_info/2,
  
  	 %for fprof
  	 get_all_pids/0]).
  
  %% for unit testing
  -export([start_link_for_unittest/0]).
  
negative.code: %% @doc register a process with InstanceId and Name
  %% @spec register_process(term(), term(), pid()) -> ok
  register_process(InstanceId, Name, Pid) ->
      erlang:put(instance_id, InstanceId),
      erlang:put(instance_name, Name),
      cs_send:send_local(get_pid() , {register_process, InstanceId, Name, Pid}),
  