diff --git a/examples/ccn-lite-client/HOWTO b/examples/ccn-lite-client/HOWTO
index 7d038ac4d86fe312b22fc59c02bca41f23973388..010ac451bbcff4dc0ebd86d3bce6ac9a9b9dd97f 100644
--- a/examples/ccn-lite-client/HOWTO
+++ b/examples/ccn-lite-client/HOWTO
@@ -4,7 +4,7 @@ simple appserver (all in one shell)
 0. create tap devices: *./cpu/native/tapsetup.sh create 3*
 1. build ccn-lite-client: *make -B clean all-valgrind*
 2. start: *./bin/native/ccn-lite-client.elf tap0* (valgrind support included)
-3. optinonal: *config 20* [enter] (this sets the content store size)
+3. optional: *config 20* [enter] (this sets the content store size)
 4. start appserver thread: *appserver* [enter] (this starts the userland appserver, which registers for "/riot/appserver/"
 5. request content: *interest /riot/appserver/test* [enter] (ask the relay for this "file", userland code splits this up in
 chunks and requests them from the relay. In the relay the name "/riot/appserver" is registered to the RIOT MSG face with
diff --git a/sys/include/fd.h b/sys/include/fd.h
index 9ba52b260d600b154364c89511e6a66c309b1c26..e03b16aa25afa7c504a7b065194081f431dd6b6b 100644
--- a/sys/include/fd.h
+++ b/sys/include/fd.h
@@ -34,13 +34,13 @@ extern "C" {
  */
 typedef struct {
     /** private status of this fd_t */
-    int __active;
+    int internal_active;
 
-    /** the internal filedescriptor */
-    int fd;
+    /** Stores the RIOT internal value for the file descriptor (not POSIX). */
+    int internal_fd;
 
     /**
-     * Read *n* into *buf* from *fd*.  Return the
+     * Read *n* bytes into *buf* from *fd*.  Return the
      * number read, -1 for errors or 0 for EOF.
      */
     ssize_t (*read)(int fd, void *buf, size_t n);
diff --git a/sys/posix/fd.c b/sys/posix/fd.c
index 9acc595139bdbcef81f3e160a10898f199d136a3..8f40bbda354ed6ecac257820e87061eaad44c972 100644
--- a/sys/posix/fd.c
+++ b/sys/posix/fd.c
@@ -43,8 +43,8 @@ int fd_init(void)
 #ifdef MODULE_UART0
     posix_open(uart0_handler_pid, 0);
     fd_t fd = {
-        .__active = 1,
-        .fd = (int)uart0_handler_pid,
+        .internal_active = 1,
+        .internal_fd = (int)uart0_handler_pid,
         .read = (ssize_t ( *)(int, void *, size_t))posix_read,
         .write = (ssize_t ( *)(int, const void *, size_t))posix_write,
         .close = posix_close
@@ -61,7 +61,7 @@ static int fd_get_next_free(void)
     for (int i = 0; i < FD_MAX; i++) {
         fd_t *cur = &fd_table[i];
 
-        if (!cur->__active) {
+        if (!cur->internal_active) {
             return i;
         }
     }
@@ -77,8 +77,8 @@ int fd_new(int internal_fd, ssize_t (*internal_read)(int, void *, size_t),
 
     if (fd >= 0) {
         fd_t *fd_s = fd_get(fd);
-        fd_s->__active = 1;
-        fd_s->fd = internal_fd;
+        fd_s->internal_active = 1;
+        fd_s->internal_fd = internal_fd;
         fd_s->read = internal_read;
         fd_s->write = internal_write;
         fd_s->close = internal_close;
diff --git a/sys/posix/pnet/sys_socket.c b/sys/posix/pnet/sys_socket.c
index 781ca8576487f4ed6e228668226bafb3a2da985e..924acbe9052522bc1be33d7548d4fede74dc6cba 100644
--- a/sys/posix/pnet/sys_socket.c
+++ b/sys/posix/pnet/sys_socket.c
@@ -45,7 +45,7 @@ int socket(int domain, int type, int protocol)
 
 #define sock_func_wrapper(func, sockfd, ...) \
     ((fd_get(sockfd)) ? \
-        func(fd_get(sockfd)->fd, __VA_ARGS__) : \
+        func(fd_get(sockfd)->internal_fd, __VA_ARGS__) : \
         (errno = EBADF, -1))
 
 int accept(int socket, struct sockaddr *restrict address,
diff --git a/sys/posix/unistd.c b/sys/posix/unistd.c
index 6b6f1e2ff198179c4b5a535612593cb901b01fc7..d55ea298f25c08f9e621cb30d87a0a199cf0d7d1 100644
--- a/sys/posix/unistd.c
+++ b/sys/posix/unistd.c
@@ -27,12 +27,12 @@ int close(int fildes)
         return -1;
     }
 
-    if (fd_obj->close(fd_obj->fd) < 0) {
+    if (fd_obj->close(fd_obj->internal_fd) < 0) {
         errno = EIO;    // EINTR may not occur since RIOT has no signals yet.
         return -1;
     }
 
-    fd_destroy(fd_obj->fd);
+    fd_destroy(fd_obj->internal_fd);
 
     return 0;
 }