update README

README.md

@@ -1,9 +1,27 @@
-# SimpleFileSystem
+# rcore-fs
 
-[![Build Status](https://travis-ci.org/wangrunji0408/SimpleFileSystem-Rust.svg?branch=master)](https://travis-ci.org/wangrunji0408/SimpleFileSystem-Rust)
+[![Build Status](https://travis-ci.org/wangrunji0408/rcore-fs.svg?branch=master)](https://travis-ci.org/wangrunji0408/rcore-fs)
 
-A Rust implementation for SFS in [ucore_os_lab](https://github.com/chyyuu/ucore_os_lab) lab8.
+The file system module for [rCore OS](https://github.com/wangrunji0408/RustOS).
 
-This is the file system module of [RustOS](https://github.com/wangrunji0408/RustOS).
+## Sub-projects
 
-It can also be used in the origin ucore_os_lab, see [uCore with Rust SFS](https://github.com/wangrunji0408/ucore_os_lab/tree/rust-fs/labcodes_answer/lab8_result).
+Core:
+
+* `rcore-fs`: Interfaces and utilities that can be used in an OS.
+  * Virtual File System: `FileSystem`, `INode`
+  * Device and cache layer: `BlockDevice`, `CachedDevice`(TODO)
+  * Unit tests for VFS
+
+Specific file systems:
+
+* `rcore-fs-sfs`: Simple File System from [uCore OS](https://github.com/chyyuu/ucore_os_lab)
+* `rcore-fs-sefs`: Simple Encrypt File System 
+* `rcore-fs-fat32`: (TODO) FAT32
+* `rcore-fs-ramfs`: (TODO) RAM based FS.
+* `rcore-fs-devfs`: (TODO) Device driver as files
+
+Utilities:
+
+* `rcore-fs-fuse`: FUSE wrapper for VFS. Mount any FS to your Linux / macOS.
+* `rcore-fs-ucore`: uCore VFS wrapper for Rust VFS. Use any FS in the origin uCore. See [uCore with Rust SFS](https://github.com/wangrunji0408/ucore_os_lab/tree/rust-fs/labcodes_answer/lab8_result) for example.