diff --git a/inc/keyboard.h b/inc/keyboard.h
index 75b6a67..6ba0ac4 100644
--- a/inc/keyboard.h
+++ b/inc/keyboard.h
@@ -3,6 +3,7 @@
 
 #include "type.h"
 
+#define KEYBOARD_BUF_REG	0x60
 void	add_keyboard_buf(u8 ch);
 
 #endif /* MINIOS_KEYBOARD_H */
\ No newline at end of file
diff --git a/inc/process.h b/inc/process.h
index c8526e3..7d4d668 100644
--- a/inc/process.h
+++ b/inc/process.h
@@ -31,8 +31,11 @@ typedef struct s_proc {
 	u32		pid;		/* process id passed in from MM */
 	char		p_name[16];	/* name of the process */
 }PROCESS;
-
+#ifdef HAPPY_SNAKE
+#define PCB_SIZE 1
+#else
 #define PCB_SIZE 3
+#endif
 /* 指向当前进程pcb的指针 */
 extern PROCESS *p_proc_ready;
 /* pcb表 */
diff --git a/inc/time.h b/inc/time.h
index b29a1a9..e1c9ff8 100644
--- a/inc/time.h
+++ b/inc/time.h
@@ -6,4 +6,10 @@
 void	timecounter_inc();
 size_t	clock();
 
+void 	change_8253Counter0(int hertz);
+#define TIMER0		0x40
+#define TIMER_MODEREG	0x43
+#define TIMER_MODE	0x34
+#define TIMER_FREQ	1193182L
+
 #endif
\ No newline at end of file
diff --git a/inc/trap.h b/inc/trap.h
index b6c1d69..938752f 100644
--- a/inc/trap.h
+++ b/inc/trap.h
@@ -72,7 +72,7 @@ void	exception_handler(int vec_no, int err_code, int eip,
 /* 外设中断实际处理函数(C接口) */
 void	default_interrupt_handler(int irq);
 void	clock_interrupt_handler(int irq);
-
+void 	keyboard_interrupt_handler(int irq);
 /* 外设中断实际处理函数表 */
 extern void (*irq_table[])(int);
 
diff --git a/inc/type.h b/inc/type.h
index 0a95dc3..895dcb7 100644
--- a/inc/type.h
+++ b/inc/type.h
@@ -4,6 +4,7 @@
 #ifndef NULL
 #define NULL ((void*) 0)
 #endif
+// #define HAPPY_SNAKE
 
 typedef _Bool bool;
 enum { false, true };
diff --git a/kern/keyboard.c b/kern/keyboard.c
index 29a4792..8736226 100644
--- a/kern/keyboard.c
+++ b/kern/keyboard.c
@@ -1,6 +1,7 @@
 #include "keymap.h"
 #include "stdio.h"
 #include "type.h"
+#include "x86.h"
 
 #define KB_INBUF_SIZE 4
 
@@ -23,6 +24,14 @@ static KB_INPUT kb_input = {
 void
 add_keyboard_buf(u8 ch)
 {
+	if (kb_input.count < KB_INBUF_SIZE) {
+		*(kb_input.p_head) = ch;
+		kb_input.p_head ++;
+		if (kb_input.p_head == kb_input.buf + KB_INBUF_SIZE) {
+			kb_input.p_head = kb_input.buf;
+		}
+		kb_input.count ++;
+	}
 }
 
 /*
@@ -32,5 +41,18 @@ add_keyboard_buf(u8 ch)
 u8
 getch(void)
 {
-	return -1;
+	if (kb_input.count == 0)
+		return -1;
+	else {
+		// disable_int();
+		// in user mode, cli and sti will only cause protection exception
+		u8 val = *(kb_input.p_tail);
+		kb_input.p_tail ++;
+		if (kb_input.p_tail == kb_input.buf + KB_INBUF_SIZE) {
+			kb_input.p_tail = kb_input.buf;
+		}
+		kb_input.count --;
+		// enable_int();
+		return val;
+	}
 }
\ No newline at end of file
diff --git a/kern/main.c b/kern/main.c
index 919620f..a60c7cd 100644
--- a/kern/main.c
+++ b/kern/main.c
@@ -6,6 +6,9 @@
 #include "type.h"
 #include "trap.h"
 #include "x86.h"
+#include "time.h"
+#include "keyboard.h"
+#include "game.h"
 
 /*
  * 三个测试函数，用户进程的执行流
@@ -13,8 +16,12 @@
 void TestA()
 {
 	int i = 0;
+	u8 ch;
 	while(1){
-		kprintf("A%d.",i++);
+		if ((ch = getch()) != 255) {
+			kprintf("%c", ch);
+		}
+		// kprintf("A%d.",i++);
 		for (int j = 0 ; j < 5e7 ; j++)
 			;//do nothing
 	}
@@ -24,7 +31,7 @@ void TestB()
 {
 	int i = 0;
 	while(1){
-		kprintf("B%d.",i++);
+		// kprintf("B%d.",i++);
 		for (int j = 0 ; j < 5e7 ; j++)
 			;//do nothing
 	}
@@ -34,7 +41,7 @@ void TestC()
 {
 	int i = 0;
 	while(1){
-		kprintf("C%d.",i++);
+		// kprintf("C%d.",i++);
 		for (int j = 0 ; j < 5e7 ; j++)
 			;//do nothing
 	}
@@ -49,6 +56,14 @@ char process_stack[STACK_TOTSIZE];
 PROCESS *p_proc_ready;
 // pcb表
 PROCESS	proc_table[PCB_SIZE];
+#ifdef HAPPY_SNAKE
+void (*entry[]) = {
+	startGame
+};
+char pcb_name[][16] = {
+	"SNAKE"
+};
+#else 
 void (*entry[]) = {
 	TestA,
 	TestB,
@@ -59,7 +74,7 @@ char pcb_name[][16] = {
 	"TestB",
 	"TestC",
 };
-
+#endif
 /*
  * 内核的main函数
  * 用于初始化用户进程，然后将执行流交给用户进程
@@ -94,8 +109,9 @@ void kernel_main()
 
 	p_proc_ready = proc_table;
 
+	change_8253Counter0(1000);
 	enable_irq(CLOCK_IRQ);
-
+	enable_irq(KEYBOARD_IRQ);
 	restart();
 	assert(0);
 }
\ No newline at end of file
diff --git a/kern/time.c b/kern/time.c
index e080889..385eea4 100644
--- a/kern/time.c
+++ b/kern/time.c
@@ -1,5 +1,6 @@
 #include "type.h"
 #include "time.h"
+#include "x86.h"
 
 static size_t timecounter;
 
@@ -19,4 +20,17 @@ size_t
 clock()
 {
 	return timecounter;
+}
+
+void
+change_8253Counter0(int hertz) {
+	outb(TIMER_MODEREG, TIMER_MODE);
+	outb(TIMER0, (u8)(TIMER_FREQ / hertz));
+	outb(TIMER0, (u8)((TIMER_FREQ / hertz) >> 8));
+	/*
+	8253's counter is 2bytes long
+	port 0x43 be the Mode Control Register
+	Orange book writes 00_11_010_0 into this reg, which means
+	SelectCounter0 | RW low byte first and then high byte | rate generator mode | binary counter
+	*/
 }
\ No newline at end of file
diff --git a/kern/trap.c b/kern/trap.c
index 7d268fb..fdd6c01 100644
--- a/kern/trap.c
+++ b/kern/trap.c
@@ -4,6 +4,8 @@
 #include "time.h"
 #include "trap.h"
 #include "x86.h"
+#include "keymap.h"
+#include "keyboard.h"
 
 /*
  * 当前内核需要处理中断的数量
@@ -12,7 +14,7 @@ int k_reenter;
 
 void (*irq_table[16])(int) = {
 	clock_interrupt_handler,
-	default_interrupt_handler,
+	keyboard_interrupt_handler,
 	default_interrupt_handler,
 	default_interrupt_handler,
 	default_interrupt_handler,
@@ -101,10 +103,29 @@ exception_handler(int vec_no, int err_code, int eip, int cs, int eflags)
 void
 clock_interrupt_handler(int irq)
 {
-	kprintf("#");
+	static unsigned int _sched_count = 0;
+	// kprintf("i%d", clock());
 	timecounter_inc();
-	p_proc_ready++;
+	_sched_count ++;
+	if (p_proc_ready == proc_table) {
+		_sched_count ++;
+		if (_sched_count >= 20) {
+			p_proc_ready ++;
+			_sched_count = 0;
+		}
+	} else {
+		p_proc_ready ++;
+	}
 	if (p_proc_ready >= proc_table + PCB_SIZE) {
 		p_proc_ready = proc_table;
 	}
+}
+
+void keyboard_interrupt_handler(int irq) {
+	// kprintf("K");
+	u8 scode = inb(KEYBOARD_BUF_REG);
+	if (scode < sizeof(keymap) && keymap[scode] >= 'a' && keymap[scode] <= 'z') {
+		add_keyboard_buf(keymap[scode]); //only keep a-z MAKE CODE
+		// kprintf("%c", keymap[scode]);
+	} 
 }
\ No newline at end of file