diff --git a/dev/README.md b/dev/README.md
new file mode 100644
index 000000000..406cf66ff
--- /dev/null
+++ b/dev/README.md
@@ -0,0 +1 @@
+this folder contains codes under development
diff --git a/rank/xgboost_rank.h b/dev/rank/xgboost_rank.h
similarity index 100%
rename from rank/xgboost_rank.h
rename to dev/rank/xgboost_rank.h
diff --git a/rank/xgboost_rank_data.h b/dev/rank/xgboost_rank_data.h
similarity index 100%
rename from rank/xgboost_rank_data.h
rename to dev/rank/xgboost_rank_data.h
diff --git a/rank/xgboost_rank_eval.h b/dev/rank/xgboost_rank_eval.h
similarity index 100%
rename from rank/xgboost_rank_eval.h
rename to dev/rank/xgboost_rank_eval.h
diff --git a/rank/xgboost_rank_main.cpp b/dev/rank/xgboost_rank_main.cpp
similarity index 100%
rename from rank/xgboost_rank_main.cpp
rename to dev/rank/xgboost_rank_main.cpp
diff --git a/rank/xgboost_sample.h b/dev/rank/xgboost_sample.h
similarity index 100%
rename from rank/xgboost_sample.h
rename to dev/rank/xgboost_sample.h