diff --git a/include/proto.h b/include/proto.h
index dc7a860..a7b1ce1 100644
--- a/include/proto.h
+++ b/include/proto.h
@@ -39,7 +39,6 @@ void keyboard_read();
 
 /* tty.c */
 // added by mingxuan 2019-5-19
-void in_process(TTY *p_tty, u32 key);
 void task_tty();
 void tty_write(NTTY *tty, char *buf, int len);
 int tty_read(NTTY *tty, char *buf, int len);
diff --git a/include/tty.h b/include/tty.h
index 3e9f2db..bcc0358 100644
--- a/include/tty.h
+++ b/include/tty.h
@@ -27,28 +27,6 @@
 #define TTY_STATE_WAIT_SPACE 2 /*010*/
 #define TTY_STATE_DISPLAY 1	   /*001*/
 
-struct s_tty;
-struct s_console;
-
-/* TTY */
-typedef struct s_tty
-{
-	u32 ibuf[TTY_IN_BYTES]; /* TTY input buffer */
-	u32 *ibuf_head;			/* the next free slot */
-	u32 *ibuf_tail;			/* 缓冲区显示位置指针 */
-	u32 *ibuf_read;
-	int ibuf_cnt; /* how many */
-	int ibuf_read_cnt;
-	int status;
-
-	int mouse_left_button;
-	int mouse_mid_button;
-	int mouse_X;
-	int mouse_Y;
-
-	struct s_console *console;
-} TTY;
-
 typedef struct n_tty
 {
 	int driver_type; // 1-vga&kbd; 2-serial
@@ -110,7 +88,6 @@ NTTY *get_tty(const int nr_tty);
 void vga_tty_init(NTTY *tty);
 void vga_tty_write(NTTY *tty, char ch);
 void vga_tty_flush(NTTY *tty);
-void vga_tty_backspace(NTTY *tty);
 void vga_tty_scroll(NTTY *tty, int direction);
 void vga_tty_select(NTTY *tty);
 
diff --git a/kernel/global.c b/kernel/global.c
index 5eee110..1ee7d94 100644
--- a/kernel/global.c
+++ b/kernel/global.c
@@ -78,6 +78,3 @@ system_call sys_call_table[NR_SYS_CALL] = {
     sys_createdir,  // added by mingxuan 2019-5-17
     sys_deletedir   // added by mingxuan 2019-5-17
 };
-
-TTY tty_table[NR_CONSOLES];         // added by mingxuan 2019-5-19
-CONSOLE console_table[NR_CONSOLES]; // added by mingxuan 2019-5-19
\ No newline at end of file
diff --git a/kernel/vga.c b/kernel/vga.c
index fe8452b..3c0b072 100644
--- a/kernel/vga.c
+++ b/kernel/vga.c
@@ -633,23 +633,6 @@ void vga_tty_write(NTTY *tty, char ch)
 	// kprintf("row: %d; ", vga->cur_row);
 }
 
-void vga_tty_backspace(NTTY *tty)
-{
-	vga_buf *vga = tty->output_buf;
-	u16 *buf = vga->buf;
-	if (vga->cur_col == 0)
-	{
-		vga->cur_col = SCR_WIDTH - 1;
-		vga->scr_cur_line = LASTLINE(vga->scr_cur_line);
-	}
-	else
-	{
-		vga->cur_col--;
-	}
-	buf[INDEX(vga->scr_cur_line, vga->cur_col)] = BLANK;
-	vga->cur_row = CYCLE_SUB(vga->scr_top_line, vga->scr_cur_line, SCR_MAXLINE);
-}
-
 void vga_tty_flush(NTTY *tty)
 {
 	vga_buf *vga = tty->output_buf;