diff --git a/include/common.h b/include/common.h
index 759ab93..95607f8 100644
--- a/include/common.h
+++ b/include/common.h
@@ -2,7 +2,7 @@
 #define CRASHPOWEROS_COMMON_H
 
 #define OS_NAME "CrashPowerDOS"
-#define OS_VERSION "v0.2.0"
+#define OS_VERSION "v0.2.1"
 
 #include <stddef.h>
 #include <stdint.h>
diff --git a/include/memory.h b/include/memory.h
index 0ef8493..af5e5ad 100644
--- a/include/memory.h
+++ b/include/memory.h
@@ -6,7 +6,7 @@
 #include "isr.h"
 
 #define KHEAP_INITIAL_SIZE 0xf00000
-#define KHEAP_START 0xc0000000
+#define KHEAP_START      0xc0000000
 #define STACK_SIZE 32768
 
 #define INDEX_FROM_BIT(a) (a / (8*4))
@@ -43,6 +43,8 @@ typedef union header {
     ALIGN stub;
 } header_t;
 
+uint32_t memory_usage();
+
 void *memcpy(void *dst_, const void *src_, uint32_t size);
 
 int memcmp(const void *a_, const void *b_, uint32_t size);
diff --git a/include/shell.h b/include/shell.h
index 59b9066..2e52337 100644
--- a/include/shell.h
+++ b/include/shell.h
@@ -12,5 +12,11 @@ void setup_shell();
 void cmd_echo(int argc,char **argv);
 void cmd_proc();
 void cmd_date();
+void cmd_reset();
+void cmd_del(int argc, char **argv);
+void cmd_mkdir(int argc, char **argv);
+void cmd_read(int argc, char **argv);
+void cmd_cat(int argc, char **argv);
+void cmd_ls();
 
 #endif //CRASHPOWEROS_SHELL_H
diff --git a/include/task.h b/include/task.h
index 34544a4..97c4ebf 100644
--- a/include/task.h
+++ b/include/task.h
@@ -21,17 +21,13 @@ struct context {
     uint32_t eflags;
 };
 
-struct mm_struct {
-    page_directory_t *pgd_dir;     // 进程页表
-};
-
 // 进程控制块 PCB
 struct task_struct {
     volatile task_state state;  // 进程当前状态
     int pid;           // 进程标识符
     char *name;        // 进程名
     void *stack;         // 进程的内核栈地址
-    struct mm_struct *mm;       // 当前进程的内存地址映像
+    page_directory_t *pgd_dir;     // 进程页表
     struct context context;     // 进程切换需要的上下文信息
     struct task_struct *next;   // 链表指针
 };
diff --git a/kernel/kernel.c b/kernel/kernel.c
index 916d328..03fdada 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -13,7 +13,6 @@
 extern uint32_t end;
 uint32_t placement_address = (uint32_t) & end;
 
-
 void kernel_main() {
     io_cli();
     vga_install();
@@ -28,6 +27,7 @@ void kernel_main() {
     printf("[kernel]: PCB load success!\n");
     init_keyboard();
     printf("[kernel]: Keyboard driver load success!\n");
+
     print_cpu_id();
     io_sti();
 
diff --git a/kernel/kheap.c b/kernel/kheap.c
index 42a6a7a..2e7f491 100644
--- a/kernel/kheap.c
+++ b/kernel/kheap.c
@@ -6,6 +6,18 @@ extern uint32_t end; // declared in linker.ld
 static uint32_t placement_address = (uint32_t) &end;
 void *program_break, *program_break_end;
 
+uint32_t memory_usage(){
+    header_t *curr = head;
+    uint32_t size;
+    while (curr) {
+        if(!curr->s.is_free){
+            size += curr->s.size;
+        }
+        curr = curr->s.next;
+    }
+    return size;
+}
+
 static uint32_t kmalloc_int(uint32_t sz, uint32_t align, uint32_t *phys) {
     if (program_break) {
         // 有内存堆
@@ -24,6 +36,7 @@ static uint32_t kmalloc_int(uint32_t sz, uint32_t align, uint32_t *phys) {
     if (phys) *phys = placement_address;
     uint32_t tmp = placement_address;
     placement_address += sz;
+
     return tmp;
 }
 
diff --git a/kernel/task.c b/kernel/task.c
index ce929df..f6122e1 100644
--- a/kernel/task.c
+++ b/kernel/task.c
@@ -6,6 +6,8 @@ struct task_struct *running_proc_head = NULL;
 struct task_struct *wait_proc_head = NULL;
 struct task_struct *current = NULL;
 
+extern page_directory_t *kernel_directory;
+
 extern void switch_to(struct context *prev, struct context *next);
 
 int now_pid = 0;
@@ -62,7 +64,10 @@ void print_proc(){
 
 void schedule() {
     if (current) {
-        change_task_to(current->next);
+        volatile task_state state = current->next->state;
+        if(state == TASK_RUNNABLE || state == TASK_SLEEPING ){
+            change_task_to(current->next);
+        }
     }
 }
 
@@ -70,6 +75,7 @@ void change_task_to(struct task_struct *next) {
     if (current != next) {
         struct task_struct *prev = current;
         current = next;
+        //switch_page_directory(current->pgd_dir);
         switch_to(&(prev->context), &(current->context));
     }
 }
@@ -84,7 +90,8 @@ int32_t kernel_thread(int (*fn)(void *), void *arg,char* name) {
     new_task->state = TASK_RUNNABLE;
     new_task->stack = current;
     new_task->pid = now_pid++;
-    new_task->mm = NULL;
+    new_task->pgd_dir = (page_directory_t *) kmalloc_a(sizeof(page_directory_t));
+
     new_task->name = name;
 
     uint32_t *stack_top = (uint32_t * )((uint32_t) new_task + STACK_SIZE);
@@ -125,7 +132,7 @@ void init_sched() {
     current->state = TASK_RUNNABLE;
     current->pid = now_pid++;
     current->stack = current;   // 该成员指向栈低地址
-    current->mm = NULL;         // 内核线程不需要该成员
+    current->pgd_dir = kernel_directory;
     current->name = "CPOS-System";
 
     current->next = current;
diff --git a/sysapp/date.c b/sysapp/date.c
index 7733a4c..c722013 100644
--- a/sysapp/date.c
+++ b/sysapp/date.c
@@ -13,7 +13,7 @@ int setup_date(){
         clock_sleep(5);
         date_info = get_date_time(); //11
         i = 0;
-        for(size_t x = VGA_WIDTH - 17; x < VGA_WIDTH ; x++){
+        for(size_t x = VGA_WIDTH - 19; x < VGA_WIDTH ; x++){
             const size_t index = (VGA_HEIGHT - 1) * VGA_WIDTH + x;
             terminal_buffer[index] = vga_entry(date_info[i],terminal_color);
             i++;
diff --git a/sysapp/shell.c b/sysapp/shell.c
index 64d5127..72410ca 100644
--- a/sysapp/shell.c
+++ b/sysapp/shell.c
@@ -2,17 +2,17 @@
 #include "../include/queue.h"
 #include "../include/vga.h"
 #include "../include/common.h"
-#include "../include/io.h"
 #include "../include/task.h"
 #include "../include/cmos.h"
 #include "../include/fat16.h"
+#include "../include/timer.h"
+#include "../include/io.h"
 
 extern Queue *key_char_queue;
 
 char getc() {
     while (key_char_queue->size == 0x00) {
-        io_hlt();
-
+        printf("");
     }
     return queue_pop(key_char_queue);
 }
@@ -73,7 +73,9 @@ void cmd_proc(){
 
 void cmd_date(){
     printf("System Time:           %s\n",get_date_time());
+    printf("Memory Usage: %dKB | All Size: %dMB\n",memory_usage()/1024,(KHEAP_START+KHEAP_INITIAL_SIZE)/1024/1024);
     print_cpu_id();
+    vga_writestring("\n");
 }
 
 void cmd_ls() {
@@ -161,6 +163,12 @@ void cmd_del(int argc, char **argv) {
     kfree(info);
 }
 
+void cmd_reset(){
+    printf("Restart %s for x86...");
+    clock_sleep(10);
+    outb(0x64,0xfe);
+}
+
 void setup_shell(){
     vga_clear();
     printf("%s for x86 [Version %s] \n",OS_NAME, OS_VERSION);
@@ -200,6 +208,8 @@ void setup_shell(){
             cmd_mkdir(argc, argv);
         else if (!strcmp("del", argv[0]) || !strcmp("rm", argv[0]))
             cmd_del(argc, argv);
+        else if (!strcmp("reset", argv[0]))
+            cmd_reset();
         else if (!strcmp("help", argv[0]) || !strcmp("?", argv[0]) || !strcmp("h", argv[0])) {
             vga_writestring("-=[CrashPowerShell Helper]=-\n");
             vga_writestring("help ? h           Print shell help info.\n");
@@ -212,6 +222,7 @@ void setup_shell(){
             vga_writestring("del rm     <name>  Delete a file\n");
             vga_writestring("sysinfo            Print system info.\n");
             vga_writestring("proc               Lists all running processes.\n");
+            vga_writestring("reset              Reset OS.\n");
         } else printf("[Shell]: Unknown command '%s'.\n", argv[0]);
     }
 }