diff --git a/components/dfs/filesystems/elmfat/dfs_elm.c b/components/dfs/filesystems/elmfat/dfs_elm.c
index 43facf04ebda29fda2513e84780fb6e0cc4ede02..a130e40ff85220fb27718c1ac495aa642948eed6 100644
--- a/components/dfs/filesystems/elmfat/dfs_elm.c
+++ b/components/dfs/filesystems/elmfat/dfs_elm.c
@@ -1,9 +1,12 @@
-#include <dfs_fs.h>
-#include <dfs_def.h>
-
 #include "ffconf.h"
 #include "ff.h"
 
+/* ELM FatFs provide a DIR struct */
+#define HAVE_DIR_STRUCTURE
+
+#include <dfs_fs.h>
+#include <dfs_def.h>
+
 static rt_device_t disk[_DRIVES] = {0};
 
 static int elm_result_to_dfs(FRESULT result)
@@ -67,7 +70,7 @@ int dfs_elm_mount(struct dfs_filesystem* fs, unsigned long rwflag, const void* d
 			break;
 		}
 	}
-	if (index == _DRIVES) return -DFS_STATUS_EMMOUNT;
+	if (index == _DRIVES) return -DFS_STATUS_ENOSPC;
 
 	/* get device */
 	disk[index] = fs->dev_id;
@@ -94,14 +97,31 @@ int dfs_elm_mount(struct dfs_filesystem* fs, unsigned long rwflag, const void* d
 int dfs_elm_unmount(struct dfs_filesystem* fs)
 {
 	FATFS *fat;
+	FRESULT result;
+	rt_uint32_t index;
+
 	fat = (FATFS*) fs->data;
 
 	RT_ASSERT(fat != RT_NULL);
 
-	/* elm not support unmount */
-	rt_kprintf("elm fatfs not support unmount\n");
+	/* find the device index and then umount it */
+	for (index = 0; index < _DRIVES; index ++)
+	{
+		if (disk[index] == fs->dev_id)
+		{
+			result = f_mount(index, RT_NULL);
 
-	return 0;
+			if (result == FR_OK)
+			{
+				fs->data = RT_NULL;
+				disk[index] = RT_NULL;
+				rt_free(fat);
+				return DFS_STATUS_OK;
+			}
+		}
+	}
+
+	return -DFS_STATUS_ENOENT;
 }
 
 int dfs_elm_mkfs(const char* device_name)
@@ -134,7 +154,7 @@ int dfs_elm_mkfs(const char* device_name)
 	return -DFS_STATUS_EIO;
 }
 
-int dfs_elm_statfs(struct dfs_filesystem* fs, struct _statfs *buf)
+int dfs_elm_statfs(struct dfs_filesystem* fs, struct statfs *buf)
 {
 	FATFS *f;
 	FRESULT res;
@@ -374,19 +394,19 @@ int dfs_elm_lseek(struct dfs_fd* file, rt_off_t offset)
 	return elm_result_to_dfs(result);
 }
 
-int dfs_elm_getdents(struct dfs_fd* file, struct _dirent* dirp, rt_uint32_t count)
+int dfs_elm_getdents(struct dfs_fd* file, struct dirent* dirp, rt_uint32_t count)
 {
 	DIR* dir;
 	FILINFO fno;
 	FRESULT result;
 	rt_uint32_t index;
-	struct _dirent* d;
+	struct dirent* d;
 
 	dir = (DIR*)(file->data);
 	RT_ASSERT(dir != RT_NULL);
 
 	/* make integer count */
-	count = (count / sizeof(struct _dirent)) * sizeof(struct _dirent);
+	count = (count / sizeof(struct dirent)) * sizeof(struct dirent);
 	if ( count == 0 ) return -DFS_STATUS_EINVAL;
 
 #if _USE_LFN
@@ -416,11 +436,11 @@ int dfs_elm_getdents(struct dfs_fd* file, struct _dirent* dirp, rt_uint32_t coun
 		else d->d_type = DFS_DT_REG;
 
 		d->d_namlen = rt_strlen(fn);
-		d->d_reclen = (rt_uint16_t)sizeof(struct _dirent);
+		d->d_reclen = (rt_uint16_t)sizeof(struct dirent);
 		rt_strncpy(d->d_name, fn, rt_strlen(fn) + 1);
 
 		index ++;
-		if ( index * sizeof(struct _dirent) >= count )
+		if ( index * sizeof(struct dirent) >= count )
 			break;
 	}
 
@@ -431,7 +451,7 @@ int dfs_elm_getdents(struct dfs_fd* file, struct _dirent* dirp, rt_uint32_t coun
 	if (index == 0)
 		return elm_result_to_dfs(result);
 
-	return index * sizeof(struct _dirent);
+	return index * sizeof(struct dirent);
 }
 
 int dfs_elm_unlink(struct dfs_filesystem* fs, const char* path)
@@ -501,7 +521,7 @@ int dfs_elm_rename(struct dfs_filesystem* fs, const char* oldpath, const char* n
 	return elm_result_to_dfs(result);
 }
 
-int dfs_elm_stat(struct dfs_filesystem* fs, const char *path, struct _stat *st)
+int dfs_elm_stat(struct dfs_filesystem* fs, const char *path, struct stat *st)
 {
 	FILINFO file_info;
 	FRESULT result;
diff --git a/components/dfs/filesystems/nfs/dfs_nfs.c b/components/dfs/filesystems/nfs/dfs_nfs.c
index 5824dfd806bf45219c8874a2b1b6c97cc382239e..a463b0dab4cf1132300b89b01f79480314369e1b 100644
--- a/components/dfs/filesystems/nfs/dfs_nfs.c
+++ b/components/dfs/filesystems/nfs/dfs_nfs.c
@@ -722,7 +722,7 @@ int nfs_open(struct dfs_fd* file)
 	return 0;
 }
 
-int nfs_stat(struct dfs_filesystem* fs, const char *path, struct _stat *st)
+int nfs_stat(struct dfs_filesystem* fs, const char *path, struct stat *st)
 {
 	GETATTR3args args;
 	GETATTR3res res;
@@ -984,11 +984,11 @@ int nfs_rename(struct dfs_filesystem* fs, const char *src, const char *dest)
 	return ret;
 }
 
-int nfs_getdents(struct dfs_fd* file, struct _dirent* dirp, rt_uint32_t count)
+int nfs_getdents(struct dfs_fd* file, struct dirent* dirp, rt_uint32_t count)
 {
 	nfs_dir *dir;
 	rt_uint32_t index;
-	struct _dirent* d;
+	struct dirent* d;
 	struct nfs_filesystem* nfs;
 	char *name;
 
@@ -999,7 +999,7 @@ int nfs_getdents(struct dfs_fd* file, struct _dirent* dirp, rt_uint32_t count)
 	nfs = (struct nfs_filesystem *)file->fs->data;
 
 	/* make integer count */
-	count = (count / sizeof(struct _dirent)) * sizeof(struct _dirent);
+	count = (count / sizeof(struct dirent)) * sizeof(struct dirent);
 	if ( count == 0 ) return -DFS_STATUS_EINVAL;
 
 	index = 0;
@@ -1015,15 +1015,15 @@ int nfs_getdents(struct dfs_fd* file, struct _dirent* dirp, rt_uint32_t count)
 		d->d_type &= DFS_DT_REG;
 
 		d->d_namlen = rt_strlen(name);
-		d->d_reclen = (rt_uint16_t)sizeof(struct _dirent);
+		d->d_reclen = (rt_uint16_t)sizeof(struct dirent);
 		rt_strncpy(d->d_name, name, rt_strlen(name) + 1);
 
 		index ++;
-		if ( index * sizeof(struct _dirent) >= count )
+		if ( index * sizeof(struct dirent) >= count )
 			break;
 	}
 
-	return index * sizeof(struct _dirent);
+	return index * sizeof(struct dirent);
 }
 
 static const struct dfs_filesystem_operation _nfs = 
diff --git a/components/dfs/filesystems/nfs/rpc/types.h b/components/dfs/filesystems/nfs/rpc/types.h
index 29f16cccb35a1d224158ab4c61af6abc5f225e74..d16f8bca9f5e94cabf131e3ff2b3d92f8f8a52c8 100644
--- a/components/dfs/filesystems/nfs/rpc/types.h
+++ b/components/dfs/filesystems/nfs/rpc/types.h
@@ -43,7 +43,6 @@
 typedef unsigned int u_int;
 typedef unsigned char u_char;
 typedef unsigned long u_long;
-#endif
 
 typedef rt_int8_t   int8_t;
 typedef rt_uint8_t  uint8_t;
@@ -51,6 +50,10 @@ typedef rt_int16_t  int16_t;
 typedef rt_uint16_t uint16_t;
 typedef rt_int32_t  int32_t;
 typedef rt_uint32_t uint32_t;
+#else
+#include <sys/types.h>
+#include <stdint.h>
+#endif
 
 typedef long long   int64_t;
 typedef unsigned long long uint64_t;
@@ -60,7 +63,6 @@ typedef int enum_t;
 
 #ifndef RT_USING_NEWLIB
 typedef rt_int32_t  ssize_t;
-typedef unsigned long mode_t;
 typedef unsigned long dev_t;
 #endif
 
diff --git a/components/dfs/filesystems/skeleton/skeleton.c b/components/dfs/filesystems/skeleton/skeleton.c
new file mode 100644
index 0000000000000000000000000000000000000000..516879d59ea6670e4da41cd74b7ba16722a66830
--- /dev/null
+++ b/components/dfs/filesystems/skeleton/skeleton.c
@@ -0,0 +1,81 @@
+/*
+ * A skeleton of file system in Device File System
+ */
+#include <rtthread.h>
+#include <dfs.h>
+#include <dfs_fs.h>
+
+#include "dfs_skt_fs.h"
+
+int dfs_skt_mount(struct dfs_filesystem* fs, unsigned long rwflag, const void* data)
+{
+	return DFS_STATUS_OK;
+}
+
+int dfs_skt_unmount(struct dfs_filesystem* fs)
+{
+	return DFS_STATUS_OK;
+}
+
+int dfs_skt_ioctl(struct dfs_fd* file, int cmd,	void* args)
+{
+	return -DFS_STATUS_EIO;
+}
+
+int dfs_skt_read(struct dfs_fd* file, void *buf, rt_size_t count)
+{
+	return count;
+}
+
+int dfs_skt_lseek(struct dfs_fd* file, rt_off_t offset)
+{
+	return -DFS_STATUS_EIO;
+}
+
+int dfs_skt_close(struct dfs_fd* file)
+{
+	return DFS_STATUS_OK;
+}
+
+int dfs_skt_open(struct dfs_fd* file)
+{
+	return DFS_STATUS_OK;
+}
+
+int dfs_skt_stat(struct dfs_filesystem* fs, const char *path, struct stat *st)
+{
+	return DFS_STATUS_OK;
+}
+
+int dfs_skt_getdents(struct dfs_fd* file, struct dirent* dirp, rt_uint32_t count)
+{
+	return count * sizeof(struct dirent);
+}
+
+static const struct dfs_filesystem_operation _skt_fs = 
+{
+	"skt",
+	dfs_skt_mount,
+	dfs_skt_unmount,
+	RT_NULL,
+	RT_NULL,
+
+	dfs_skt_open,
+	dfs_skt_close,
+	dfs_skt_ioctl,
+	dfs_skt_read,
+	RT_NULL,
+	RT_NULL,
+	dfs_skt_lseek,
+	dfs_skt_getdents,
+	RT_NULL,
+	dfs_skt_stat,
+	RT_NULL,
+};
+
+int dfs_skt_init(void)
+{
+    /* register rom file system */
+    dfs_register(&_skt_fs);
+	return 0;
+}
diff --git a/components/dfs/filesystems/skeleton/skeleton.h b/components/dfs/filesystems/skeleton/skeleton.h
new file mode 100644
index 0000000000000000000000000000000000000000..cacbf36b6273ad64a1f906a434bcbbbe605e143b
--- /dev/null
+++ b/components/dfs/filesystems/skeleton/skeleton.h
@@ -0,0 +1,8 @@
+#ifndef __SKELETON_H__
+#define __SKELETON_H__
+
+#include <rtthread.h>
+
+int dfs_skt_init(void);
+
+#endif
diff --git a/components/dfs/include/dfs_def.h b/components/dfs/include/dfs_def.h
index e2204870431828c6a36b63e3152261bab7519053..62ade80bd2a6b21363a2c51520f6b1511d435667 100644
--- a/components/dfs/include/dfs_def.h
+++ b/components/dfs/include/dfs_def.h
@@ -19,14 +19,115 @@
 #include <rtthread.h>
 #include <dfs_config.h>
 
-#if defined(RT_USING_NEWLIB) || defined (RT_USING_MINILIBC)
-#include <string.h>
-#endif
-
 #ifndef __D_FS__
 #define __D_FS__
 #endif
 
+#define DEVICE_GETGEOME 		0
+#define DEVICE_GETINFO			1
+#define DEVICE_FORMAT 			2
+#define DEVICE_CLEAN_SECTOR 	3
+
+/* File flags */
+#define DFS_F_OPEN			0x01000000
+#define DFS_F_DIRECTORY		0x02000000
+#define DFS_F_EOF			0x04000000
+#define DFS_F_ERR			0x08000000
+
+#if defined(RT_USING_NEWLIB) 
+#include <string.h>
+#include <sys/stat.h> 			/* used for struct stat 	*/
+#include <sys/statfs.h>			/* used for struct statfs 	*/
+#include <sys/errno.h>			/* used for error number 	*/
+#include <sys/fcntl.h>			/* used for operation flags */
+#include <sys/unistd.h>			/* used for SEEK_SET/CUR/END */
+#include <dirent.h>				/* used for struct dirent 	*/
+
+/* Device error codes */
+#define DFS_STATUS_OK			0			/* no error */
+#define DFS_STATUS_ENOENT		ENOENT		/* No such file or directory */
+#define DFS_STATUS_EIO		 	EIO			/* I/O error */
+#define DFS_STATUS_ENXIO		ENXIO		/* No such device or address */
+#define DFS_STATUS_EBADF		EBADF		/* Bad file number */
+#define DFS_STATUS_EAGAIN		EAGAIN		/* Try again */
+#define DFS_STATUS_ENOMEM		ENOMEM		/* no memory */
+#define DFS_STATUS_EBUSY		EBUSY		/* Device or resource busy */
+#define DFS_STATUS_EEXIST		EEXIST 		/* File exists */
+#define DFS_STATUS_EXDEV		EXDEV		/* Cross-device link */
+#define DFS_STATUS_ENODEV		ENODEV		/* No such device */
+#define DFS_STATUS_ENOTDIR		ENOTDIR		/* Not a directory */
+#define DFS_STATUS_EISDIR		EISDIR		/* Is a directory */
+#define DFS_STATUS_EINVAL		EINVAL		/* Invalid argument */
+#define DFS_STATUS_ENOSPC		ENOSPC		/* No space left on device */
+#define DFS_STATUS_EROFS		EROFS		/* Read-only file system */
+#define DFS_STATUS_ENOSYS		ENOSYS		/* Function not implemented */
+#define DFS_STATUS_ENOTEMPTY	ENOTEMPTY	/* Directory not empty */
+
+/* Operation flags */
+#define DFS_O_RDONLY			O_RDONLY
+#define DFS_O_WRONLY			O_WRONLY
+#define DFS_O_RDWR				O_RDWR
+#define DFS_O_ACCMODE			O_ACCMODE
+#define DFS_O_CREAT				O_CREAT
+#define DFS_O_EXCL				O_EXCL
+#define DFS_O_TRUNC				O_TRUNC
+#define DFS_O_APPEND			O_APPEND
+#define DFS_O_DIRECTORY			O_DIRECTORY
+
+/* Seek flags */
+#define DFS_SEEK_SET         	SEEK_SET
+#define DFS_SEEK_CUR         	SEEK_CUR
+#define DFS_SEEK_END         	SEEK_END
+
+/* Stat codes */
+#define DFS_S_IFMT				S_IFMT
+#define DFS_S_IFSOCK			S_IFSOCK
+#define DFS_S_IFLNK				S_IFLNK
+#define DFS_S_IFREG				S_IFREG
+#define DFS_S_IFBLK				S_IFBLK
+#define DFS_S_IFDIR  			S_IFDIR
+#define DFS_S_IFCHR  			S_IFCHR
+#define DFS_S_IFIFO  			S_IFIFO
+#define DFS_S_ISUID  			S_ISUID
+#define DFS_S_ISGID  			S_ISGID
+#define DFS_S_ISVTX  			S_ISVTX
+
+#define DFS_S_ISLNK(m)			S_ISLNK(m)
+#define DFS_S_ISREG(m)			S_ISREG(m)
+#define DFS_S_ISDIR(m)			S_ISDIR(m)
+#define DFS_S_ISCHR(m)			S_ISCHR(m)
+#define DFS_S_ISBLK(m)			S_ISBLK(m)
+#define DFS_S_ISFIFO(m)			S_ISFIFO(m)
+#define DFS_S_ISSOCK(m)			S_ISSOCK(m)
+
+#define DFS_S_IRWXU 			S_IRWXU
+#define DFS_S_IRUSR 			S_IRUSR
+#define DFS_S_IWUSR 			S_IWUSR
+#define DFS_S_IXUSR 			S_IXUSR
+
+#define DFS_S_IRWXG 			S_IRWXG
+#define DFS_S_IRGRP 			S_IRGRP
+#define DFS_S_IWGRP 			S_IWGRP
+#define DFS_S_IXGRP 			S_IXGRP
+
+#define DFS_S_IRWXO 			S_IRWXO
+#define DFS_S_IROTH 			S_IROTH
+#define DFS_S_IWOTH 			S_IWOTH
+#define DFS_S_IXOTH 			S_IXOTH
+
+/* Dirent types */
+#define DFS_DT_UNKNOWN			DT_UNKNOWN
+#define DFS_DT_REG				DT_REG
+#define DFS_DT_DIR				DT_DIR
+
+#else
+#ifdef RT_USING_MINILIBC
+#include <string.h>
+#else
+typedef long off_t;
+typedef int mode_t;
+#endif
+
 /* Device error codes */
 #define DFS_STATUS_OK			0		/* no error */
 #define DFS_STATUS_ENOENT		2		/* No such file or directory */
@@ -46,7 +147,6 @@
 #define DFS_STATUS_EROFS		30		/* Read-only file system */
 #define DFS_STATUS_ENOSYS		38		/* Function not implemented */
 #define DFS_STATUS_ENOTEMPTY	39		/* Directory not empty */
-#define DFS_STATUS_EMMOUNT		128		/* Filesystem table full */
 
 /* Operation flags */
 #define DFS_O_RDONLY		0000000
@@ -106,12 +206,7 @@
 #define DFS_S_IWOTH 	00002
 #define DFS_S_IXOTH 	00001
 
-#define DEVICE_GETGEOME 		0
-#define DEVICE_GETINFO			1
-#define DEVICE_FORMAT 			2
-#define DEVICE_CLEAN_SECTOR 	3
-
-struct _stat
+struct stat
 {
 	rt_device_t st_dev;
 	rt_uint16_t st_mode;
@@ -120,7 +215,7 @@ struct _stat
 	rt_uint32_t st_blksize;
 };
 
-struct _statfs
+struct statfs
 {
 	rt_size_t f_bsize; 	 /* block size */
 	rt_size_t f_blocks;  /* total data blocks in file system */
@@ -133,6 +228,20 @@ struct _statfs
 #define FT_DIRECTORY	2	/* directory    */
 #define FT_USER			3	/* user defined */
 
+/* Dirent types */
+#define DFS_DT_UNKNOWN	0x00
+#define DFS_DT_REG		0x01
+#define DFS_DT_DIR		0x02
+
+struct dirent
+{
+	rt_uint8_t d_type;				/* The type of the file */
+	rt_uint8_t d_namlen;			/* The length of the not including the terminating null file name */
+	rt_uint16_t d_reclen;			/* length of this record */
+	char d_name[DFS_PATH_MAX];		/* The null-terminated file name */
+};
+#endif
+
 /* file descriptor */
 struct dfs_fd
 {
@@ -149,16 +258,5 @@ struct dfs_fd
     void *data;					/* Specific file system data */
 };
 
-#define DFS_DT_UNKNOWN	0x00
-#define DFS_DT_REG		0x01
-#define DFS_DT_DIR		0x02
-
-struct _dirent
-{
-	rt_uint8_t d_type;				/* The type of the file */
-	rt_uint8_t d_namlen;			/* The length of the not including the terminating null file name */
-	rt_uint16_t d_reclen;			/* length of this record */
-	char d_name[DFS_PATH_MAX];		/* The null-terminated file name */
-};
-
 #endif
+
diff --git a/components/dfs/include/dfs_file.h b/components/dfs/include/dfs_file.h
index e0455e00c9b2c896b854ab1bf0eb98307ed3e90c..ab75916977cb06b83ef6a8bc9e8ca2759ad96953 100644
--- a/components/dfs/include/dfs_file.h
+++ b/components/dfs/include/dfs_file.h
@@ -24,11 +24,11 @@ int dfs_file_open(struct dfs_fd* fd, const char *path, int flags);
 int dfs_file_close(struct dfs_fd* fd);
 int dfs_file_ioctl(struct dfs_fd* fd, int cmd, void *args);
 int dfs_file_read(struct dfs_fd* fd, void *buf, rt_size_t len);
-int dfs_file_getdents(struct dfs_fd* fd, struct _dirent* dirp, rt_size_t nbytes);
+int dfs_file_getdents(struct dfs_fd* fd, struct dirent* dirp, rt_size_t nbytes);
 int dfs_file_unlink(const char *path);
 int dfs_file_write(struct dfs_fd* fd, const void *buf, rt_size_t len);
 int dfs_file_lseek(struct dfs_fd* fd, rt_off_t offset);
-int dfs_file_stat(const char *path, struct _stat *buf);
+int dfs_file_stat(const char *path, struct stat *buf);
 int dfs_file_rename(const char* oldpath, const char* newpath);
 
 #endif
diff --git a/components/dfs/include/dfs_fs.h b/components/dfs/include/dfs_fs.h
index d47e5c93cf0ad487df603aadecc3a7c7356c246f..d698df429b7fcca3b0cbb91a9696bad13f8c786b 100644
--- a/components/dfs/include/dfs_fs.h
+++ b/components/dfs/include/dfs_fs.h
@@ -20,7 +20,6 @@
 /* Pre-declaration */
 struct dfs_filesystem;
 struct dfs_fd;
-struct dfs_dirent;
 
 /* File system operations struct */
 struct dfs_filesystem_operation
@@ -33,7 +32,7 @@ struct dfs_filesystem_operation
 
 	/* make a file system */
 	int (*mkfs)     (const char* device_name);
-	int (*statfs)   (struct dfs_filesystem* fs, struct _statfs *buf);
+	int (*statfs)   (struct dfs_filesystem* fs, struct statfs *buf);
 
 	int (*open)		(struct dfs_fd* fd);
 	int (*close)	(struct dfs_fd* fd);
@@ -42,10 +41,10 @@ struct dfs_filesystem_operation
 	int (*write)	(struct dfs_fd* fd, const void* buf, rt_size_t count);
 	int (*flush)    (struct dfs_fd* fd);
 	int (*lseek)	(struct dfs_fd* fd, rt_off_t offset);
-	int (*getdents)	(struct dfs_fd* fd, struct _dirent* dirp, rt_uint32_t count);
+	int (*getdents)	(struct dfs_fd* fd, struct dirent* dirp, rt_uint32_t count);
 
 	int (*unlink)	(struct dfs_filesystem* fs, const char* pathname);
-	int (*stat)		(struct dfs_filesystem* fs, const char* filename, struct _stat* buf);
+	int (*stat)		(struct dfs_filesystem* fs, const char* filename, struct stat* buf);
 	int (*rename)	(struct dfs_filesystem* fs, const char* oldpath, const char* newpath);
 };
 
@@ -86,6 +85,6 @@ extern char working_directory[];
 
 void dfs_lock(void);
 void dfs_unlock(void);
-int dfs_statfs(const char* path, struct _statfs* buffer);
+int dfs_statfs(const char* path, struct statfs* buffer);
 
 #endif
diff --git a/components/dfs/include/dfs_posix.h b/components/dfs/include/dfs_posix.h
index d59421fd8de1c99d34eb4f53145aa94595703f23..7897893bef844a394e48e169b43c78599bacba5d 100644
--- a/components/dfs/include/dfs_posix.h
+++ b/components/dfs/include/dfs_posix.h
@@ -18,6 +18,7 @@
 #include <dfs_file.h>
 #include <dfs_def.h>
 
+#ifndef RT_USING_NEWLIB
 #define O_RDONLY	DFS_O_RDONLY
 #define O_WRONLY 	DFS_O_WRONLY
 #define O_RDWR		DFS_O_RDWR
@@ -75,30 +76,35 @@ typedef struct
 	int cur;
 } DIR;
 
-#define statfs _statfs
-#define dirent _dirent
+/* directory api*/
+int mkdir (const char *path, mode_t mode);
+DIR* opendir(const char* name);
+struct dirent* readdir(DIR *d);
+long telldir(DIR *d);
+void seekdir(DIR *d, off_t offset);
+void rewinddir(DIR *d);
+int closedir(DIR* d);
+
+#else
+/* use newlib header file */
+#include <sys/stat.h>
+#endif
 
 /* file api*/
 int open(const char *file, int flags, int mode);
 int close(int d);
-int read(int fd, char *buf, int len);
-int write(int fd, char *buf, int len);
-int lseek(int fd, int offset, int dir);
+int read(int fd, void *buf, size_t len);
+int write(int fd, const void *buf, size_t len);
+off_t lseek(int fd, off_t offset, int whence);
 int rename(const char* old, const char* new );
 int unlink(const char *pathname);
-int stat(const char *file, struct _stat *buf);
-int statfs(const char *path, struct _statfs *buf);
+int stat(const char *file, struct stat *buf);
+int statfs(const char *path, struct statfs *buf);
 
 /* directory api*/
-int mkdir (const char *path, rt_uint16_t mode);
 int rmdir(const char *path);
-DIR* opendir(const char* name);
-struct _dirent* readdir(DIR *d);
-rt_off_t telldir(DIR *d);
-void seekdir(DIR *d, rt_off_t offset);
-void rewinddir(DIR *d);
-int closedir(DIR* d);
 int chdir(const char *path);
-char* getcwd(char *buf, rt_size_t size);
+char *getcwd(char *buf, size_t size);
 
 #endif
+
diff --git a/components/dfs/src/dfs_file.c b/components/dfs/src/dfs_file.c
index 0d708d82fb938394bdc7749e69acd602d62c670a..c32605209034e36387e6049185e90875fb83e3de 100644
--- a/components/dfs/src/dfs_file.c
+++ b/components/dfs/src/dfs_file.c
@@ -176,7 +176,7 @@ int dfs_file_read(struct dfs_fd* fd, void *buf, rt_size_t len)
  *
  * @return the read dirent, others on failed.
  */
-int dfs_file_getdents(struct dfs_fd* fd, struct _dirent* dirp, rt_size_t nbytes)
+int dfs_file_getdents(struct dfs_fd* fd, struct dirent* dirp, rt_size_t nbytes)
 {
 	struct dfs_filesystem* fs;
 
@@ -306,7 +306,7 @@ int dfs_file_lseek(struct dfs_fd* fd, rt_off_t offset)
  *
  * @return 0 on successful, -1 on failed.
  */
-int dfs_file_stat(const char *path, struct _stat *buf)
+int dfs_file_stat(const char *path, struct stat *buf)
 {
 	int result;
 	char* fullpath;
@@ -434,10 +434,10 @@ __exit:
 #include <finsh.h>
 
 static struct dfs_fd fd;
-static struct _dirent dirent;
+static struct dirent dirent;
 void ls(const char* pathname)
 {
-	struct _stat stat;
+	struct stat stat;
 	int length;
 	char* fullpath;
 
@@ -449,11 +449,11 @@ void ls(const char* pathname)
 		rt_kprintf("Directory %s:\n", pathname);
 		do
 		{
-			rt_memset(&dirent, 0, sizeof(struct _dirent));
-			length = dfs_file_getdents(&fd, &dirent, sizeof(struct _dirent));
+			rt_memset(&dirent, 0, sizeof(struct dirent));
+			length = dfs_file_getdents(&fd, &dirent, sizeof(struct dirent));
 			if ( length > 0 ) 
 			{
-				rt_memset(&stat, 0, sizeof(struct _stat));
+				rt_memset(&stat, 0, sizeof(struct stat));
 
 				/* build full path for each file */
 				if (pathname[strlen(pathname) - 1] != '/')
@@ -483,17 +483,6 @@ void ls(const char* pathname)
 }
 FINSH_FUNCTION_EXPORT(ls, list directory contents)
 
-static void mkdir(const char* pathname)
-{
-	/* make a new directory */
-	if (dfs_file_open(&fd, pathname, DFS_O_DIRECTORY | DFS_O_CREAT) == 0)
-	{
-		dfs_file_close(&fd);
-	}
-	else rt_kprintf("Can't mkdir %s\n", pathname);
-}
-FINSH_FUNCTION_EXPORT(mkdir, make a directory)
-
 void rm(const char* filename)
 {
 	if (dfs_file_unlink(filename) < 0)
diff --git a/components/dfs/src/dfs_fs.c b/components/dfs/src/dfs_fs.c
index 71ddb479ecf9d8e7fcc0db0a7fbb1c6ef6b92f0d..9db83a16c9188531e7586a1d8061e307030dd604 100644
--- a/components/dfs/src/dfs_fs.c
+++ b/components/dfs/src/dfs_fs.c
@@ -266,7 +266,7 @@ int dfs_mount(const char* device_name, const char* path,
             index++) ;
     if ( index == DFS_FILESYSTEMS_MAX )	/* can't find en empty filesystem table entry */
     {
-        rt_set_errno(-DFS_STATUS_EMMOUNT);
+        rt_set_errno(-DFS_STATUS_ENOSPC);
         goto err1;
     }
 
@@ -408,7 +408,7 @@ int dfs_mkfs(const char* fs_name, const char* device_name)
  *
  * @return 0 on successful, others on failed.
  */
-int dfs_statfs(const char* path, struct _statfs* buffer)
+int dfs_statfs(const char* path, struct statfs* buffer)
 {
 	struct dfs_filesystem* fs;
 
@@ -432,7 +432,7 @@ FINSH_FUNCTION_EXPORT(mkfs, make a file system);
 
 void df(const char* path)
 {
-	struct _statfs buffer;
+	struct statfs buffer;
 
 	if (dfs_statfs(path, &buffer) == 0)
 	{
diff --git a/components/dfs/src/dfs_posix.c b/components/dfs/src/dfs_posix.c
index 415ae455b1853ea0c3b29228da178aac9d41a24e..26395aafc6ac0a636cd525499b040cc21541c622 100644
--- a/components/dfs/src/dfs_posix.c
+++ b/components/dfs/src/dfs_posix.c
@@ -95,7 +95,7 @@ int close(int fd)
  *
  * @return the actual read data buffer length
  */
-int read(int fd, char *buf, int   len)
+int read(int fd, void *buf, size_t len)
 {
 	int result;
 	struct dfs_fd* d;
@@ -132,7 +132,7 @@ int read(int fd, char *buf, int   len)
  *
  * @return the actual written data buffer length.
  */
-int write(int fd, char *buf, int   len)
+int write(int fd, const void *buf, size_t len)
 {
 	int result;
 	struct dfs_fd* d;
@@ -169,7 +169,7 @@ int write(int fd, char *buf, int   len)
  *
  * @return the current file position, or -1 on failed.
  */
-int lseek(int fd, int offset, int dir)
+off_t lseek(int fd, off_t offset, int whence)
 {
 	int result;
 	struct dfs_fd* d;
@@ -181,7 +181,7 @@ int lseek(int fd, int offset, int dir)
 		return -1;
 	}
 
-	switch (dir)
+	switch (whence)
 	{
 	case DFS_SEEK_SET:
 		break;
@@ -261,7 +261,7 @@ int unlink(const char *pathname)
  *
  * @return 0 on successful, -1 on failed.
  */
-int stat(const char *file, struct _stat *buf)
+int stat(const char *file, struct stat *buf)
 {
 	int result;
 
@@ -283,7 +283,7 @@ int stat(const char *file, struct _stat *buf)
  *
  * @return 0 on successful, others on failed.
  */
-int statfs(const char *path, struct _statfs *buf)
+int statfs(const char *path, struct statfs *buf)
 {
 	int result;
 
@@ -305,7 +305,7 @@ int statfs(const char *path, struct _statfs *buf)
  *
  * @return 0 on successful, others on failed.
  */
-int mkdir (const char *path, rt_uint16_t mode)
+int mkdir (const char *path, mode_t mode)
 {
 	int fd;
 	struct dfs_fd* d;
@@ -326,6 +326,10 @@ int mkdir (const char *path, rt_uint16_t mode)
 	fd_put(d);
 	return 0;
 }
+#ifdef RT_USING_FINSH
+#include <finsh.h>
+FINSH_FUNCTION_EXPORT(mkdir, create a directory);
+#endif
 
 /**
  * this function is a POSIX compliant version, which will remove a directory.
@@ -404,7 +408,7 @@ DIR* opendir(const char* name)
  *
  * @return the next directory entry, NULL on the end of directory or failed.
  */
-struct _dirent* readdir(DIR *d)
+struct dirent* readdir(DIR *d)
 {
 	int result;
 	struct dfs_fd* fd;
@@ -416,9 +420,9 @@ struct _dirent* readdir(DIR *d)
 		return RT_NULL;
 	}
 
-	if (!d->num || (d->cur += ((struct _dirent*)(d->buf + d->cur))->d_reclen) >= d->num)
+	if (!d->num || (d->cur += ((struct dirent*)(d->buf + d->cur))->d_reclen) >= d->num)
 	{
-		result = dfs_file_getdents(fd, (struct _dirent*)d->buf, sizeof(d->buf) - 1);
+		result = dfs_file_getdents(fd, (struct dirent*)d->buf, sizeof(d->buf) - 1);
 		if (result <= 0)
 		{
 			rt_set_errno(result);
@@ -432,7 +436,7 @@ struct _dirent* readdir(DIR *d)
 	}
 
 	fd_put(fd);
-	return (struct _dirent*)(d->buf+d->cur);
+	return (struct dirent*)(d->buf+d->cur);
 }
 
 /**
@@ -443,10 +447,10 @@ struct _dirent* readdir(DIR *d)
  *
  * @return the current location in directory stream.
  */
-rt_off_t telldir(DIR *d)
+long telldir(DIR *d)
 {
 	struct dfs_fd* fd;
-	rt_off_t result;
+	long result;
 
 	fd = fd_get(d->fd);
 	if (fd == RT_NULL)
@@ -468,7 +472,7 @@ rt_off_t telldir(DIR *d)
  * @param d the directory stream.
  * @param offset the offset in directory stream.
  */
-void seekdir(DIR *d, rt_off_t offset)
+void seekdir(DIR *d, off_t offset)
 {
 	struct dfs_fd* fd;
 
@@ -589,7 +593,7 @@ int chdir(const char *path)
  *
  * @return the returned current directory.
  */
-char* getcwd(char *buf, rt_size_t size)
+char *getcwd(char *buf, size_t size)
 {
 #ifdef DFS_USING_WORKDIR
 	dfs_lock();
diff --git a/components/libc/minilibc/rand.c b/components/libc/minilibc/rand.c
index 46a96ac5bbffd7150ff2ee95008970ee1f104634..d97e91bdbac634004cdff5e07aa1033e8320b91e 100644
--- a/components/libc/minilibc/rand.c
+++ b/components/libc/minilibc/rand.c
@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <stdint.h>
 #include <sys/types.h>
 
 static unsigned int seed=1;
diff --git a/components/libc/minilibc/sys/types.h b/components/libc/minilibc/sys/types.h
index 2be1f34403c6a7b063e4ac6c591e0f39316d0a8f..fa0a236636d917ca6456b28f7fb7a8ef61d9ed22 100644
--- a/components/libc/minilibc/sys/types.h
+++ b/components/libc/minilibc/sys/types.h
@@ -3,7 +3,7 @@
 
 #include <rtthread.h>
 
-typedef rt_off_t 	off_t;
+typedef long    	off_t;
 typedef rt_size_t 	size_t;
 
 typedef rt_uint8_t 	u_char;
@@ -11,14 +11,8 @@ typedef rt_uint16_t u_short;
 typedef rt_ubase_t 	u_int;
 typedef rt_uint32_t u_long;
 
-typedef rt_uint8_t 	u_int8_t;
-typedef rt_uint16_t u_int16_t;
-typedef rt_uint32_t u_int32_t;
-typedef rt_int8_t 	int8_t;
-typedef rt_int16_t  int16_t;
-typedef rt_int32_t  int32_t;
-
 typedef rt_time_t time_t;
+typedef int mode_t;
 
 #ifndef NULL
 #define NULL RT_NULL
diff --git a/components/libc/newlib/sys/dirent.h b/components/libc/newlib/sys/dirent.h
new file mode 100644
index 0000000000000000000000000000000000000000..18c5d02e119f4d897de2fa50d7e16cb9f3c4208f
--- /dev/null
+++ b/components/libc/newlib/sys/dirent.h
@@ -0,0 +1,57 @@
+#ifndef __RTT_DIRENT_H__
+#define __RTT_DIRENT_H__
+
+#include <rtthread.h>
+
+/*
+* dirent.h - format of directory entries
+ * Ref: http://www.opengroup.org/onlinepubs/009695399/basedefs/dirent.h.html
+ */
+
+/* File types */
+#define FT_REGULAR		0	/* regular file */
+#define FT_SOCKET		1	/* socket file  */
+#define FT_DIRECTORY	2	/* directory    */
+#define FT_USER			3	/* user defined */
+
+#define DT_UNKNOWN		0x00
+#define DT_REG			0x01
+#define DT_DIR			0x02
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef HAVE_DIR_STRUCTURE
+typedef struct 
+{
+	int fd;							/* directory file */
+	char buf[512];
+	int num;
+	int cur;
+} DIR;
+#endif
+
+#ifndef HAVE_DIRENT_STRUCTURE
+struct dirent
+{
+	rt_uint8_t  d_type;				/* The type of the file */
+	rt_uint8_t  d_namlen;			/* The length of the not including the terminating null file name */
+	rt_uint16_t d_reclen;			/* length of this record */
+	char d_name[256];				/* The null-terminated file name */
+};
+#endif
+
+int            closedir(DIR *);
+DIR           *opendir(const char *);
+struct dirent *readdir(DIR *);
+int            readdir_r(DIR *, struct dirent *, struct dirent **);
+void           rewinddir(DIR *);
+void           seekdir(DIR *, long int);
+long           telldir(DIR *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/components/libc/newlib/sys/fcntl.h b/components/libc/newlib/sys/fcntl.h
new file mode 100644
index 0000000000000000000000000000000000000000..3638029eb2dfeaec497ac99d92897a801a5fcea1
--- /dev/null
+++ b/components/libc/newlib/sys/fcntl.h
@@ -0,0 +1,15 @@
+#ifndef __RTT_FCNTL_H__
+#define __RTT_FCNTL_H__
+
+/* Operation flags */
+#define O_RDONLY		0000000
+#define O_WRONLY		0000001
+#define O_RDWR			0000002
+#define O_ACCMODE		0000003
+#define O_CREAT			0000100
+#define O_EXCL			0000200
+#define O_TRUNC			0001000
+#define O_APPEND		0002000
+#define O_DIRECTORY		0200000
+
+#endif
diff --git a/components/libc/newlib/sys/statfs.h b/components/libc/newlib/sys/statfs.h
new file mode 100644
index 0000000000000000000000000000000000000000..c3bc9be3591f9df6cfd5b2afe4b677c172c44fed
--- /dev/null
+++ b/components/libc/newlib/sys/statfs.h
@@ -0,0 +1,13 @@
+#ifndef __RTT_STATFS_H__
+#define __RTT_STATFS_H__
+
+#include <rtthread.h>
+
+struct statfs
+{
+	rt_size_t f_bsize; 	 /* block size */
+	rt_size_t f_blocks;  /* total data blocks in file system */
+	rt_size_t f_bfree;	 /* free blocks in file system */
+};
+
+#endif