diff --git a/osdk/tests/examples_in_book/write_a_kernel_in_100_lines_templates/lib.rs b/osdk/tests/examples_in_book/write_a_kernel_in_100_lines_templates/lib.rs
index 542873b79..4783698a1 100644
--- a/osdk/tests/examples_in_book/write_a_kernel_in_100_lines_templates/lib.rs
+++ b/osdk/tests/examples_in_book/write_a_kernel_in_100_lines_templates/lib.rs
@@ -14,12 +14,12 @@ use alloc::vec;
 use ostd::arch::qemu::{exit_qemu, QemuExitCode};
 use ostd::cpu::UserContext;
 use ostd::mm::{
-    CachePolicy, FallibleVmRead, FallibleVmWrite, FrameAllocOptions, PageFlags, PageProperty,
-    Vaddr, VmIo, VmSpace, VmWriter, PAGE_SIZE,
+    CachePolicy, FallibleVmRead, FrameAllocOptions, PageFlags, PageProperty, Vaddr, VmIo, VmSpace,
+    VmWriter, PAGE_SIZE,
 };
 use ostd::prelude::*;
 use ostd::task::{Task, TaskOptions};
-use ostd::user::{ReturnReason, UserMode, UserSpace};
+use ostd::user::{ReturnReason, UserMode};
 
 /// The kernel's boot and initialization process is managed by OSTD.
 /// After the process is done, the kernel's execution environment
@@ -28,12 +28,13 @@ use ostd::user::{ReturnReason, UserMode, UserSpace};
 #[ostd::main]
 pub fn main() {
     let program_binary = include_bytes!("../hello");
-    let user_space = create_user_space(program_binary);
-    let user_task = create_user_task(Arc::new(user_space));
+    let vm_space = Arc::new(create_vm_space(program_binary));
+    vm_space.activate();
+    let user_task = create_user_task(vm_space);
     user_task.run();
 }
 
-fn create_user_space(program: &[u8]) -> UserSpace {
+fn create_vm_space(program: &[u8]) -> VmSpace {
     let nbytes = program.len().align_up(PAGE_SIZE);
     let user_pages = {
         let segment = FrameAllocOptions::new()
@@ -44,42 +45,29 @@ fn create_user_space(program: &[u8]) -> UserSpace {
         segment.write_bytes(0, program).unwrap();
         segment
     };
-    let user_address_space = {
-        const MAP_ADDR: Vaddr = 0x0040_0000; // The map addr for statically-linked executable
 
-        // The page table of the user space can be
-        // created and manipulated safely through
-        // the `VmSpace` abstraction.
-        let vm_space = VmSpace::new();
-        let mut cursor = vm_space.cursor_mut(&(MAP_ADDR..MAP_ADDR + nbytes)).unwrap();
-        let map_prop = PageProperty::new(PageFlags::RWX, CachePolicy::Writeback);
-        for frame in user_pages {
-            cursor.map(frame.into(), map_prop);
-        }
-        drop(cursor);
-        Arc::new(vm_space)
-    };
-    let user_cpu_state = {
-        const ENTRY_POINT: Vaddr = 0x0040_1000; // The entry point for statically-linked executable
-
-        // The user-space CPU states can be initialized
-        // to arbitrary values via the UserContext
-        // abstraction.
-        let mut user_cpu_state = UserContext::default();
-        user_cpu_state.set_rip(ENTRY_POINT);
-        user_cpu_state
-    };
-    UserSpace::new(user_address_space, user_cpu_state)
+    // The page table of the user space can be
+    // created and manipulated safely through
+    // the `VmSpace` abstraction.
+    let vm_space = VmSpace::new();
+    const MAP_ADDR: Vaddr = 0x0040_0000; // The map addr for statically-linked executable
+    let mut cursor = vm_space.cursor_mut(&(MAP_ADDR..MAP_ADDR + nbytes)).unwrap();
+    let map_prop = PageProperty::new(PageFlags::RWX, CachePolicy::Writeback);
+    for frame in user_pages {
+        cursor.map(frame.into(), map_prop);
+    }
+    drop(cursor);
+    vm_space
 }
 
-fn create_user_task(user_space: Arc<UserSpace>) -> Arc<Task> {
+fn create_user_task(vm_space: Arc<VmSpace>) -> Arc<Task> {
     fn user_task() {
         let current = Task::current().unwrap();
         // Switching between user-kernel space is
         // performed via the UserMode abstraction.
         let mut user_mode = {
-            let user_space = current.user_space().unwrap();
-            UserMode::new(user_space)
+            let user_ctx = create_user_context();
+            UserMode::new(user_ctx)
         };
 
         loop {
@@ -93,7 +81,8 @@ fn create_user_task(user_space: Arc<UserSpace>) -> Arc<Task> {
             // the `UserContext` abstraction.
             let user_context = user_mode.context_mut();
             if ReturnReason::UserSyscall == return_reason {
-                handle_syscall(user_context, current.user_space().unwrap());
+                let vm_space = current.data().downcast_ref::<Arc<VmSpace>>().unwrap();
+                handle_syscall(user_context, &vm_space);
             }
         }
     }
@@ -101,16 +90,20 @@ fn create_user_task(user_space: Arc<UserSpace>) -> Arc<Task> {
     // Kernel tasks are managed by the Framework,
     // while scheduling algorithms for them can be
     // determined by the users of the Framework.
-    Arc::new(
-        TaskOptions::new(user_task)
-            .user_space(Some(user_space))
-            .data(0)
-            .build()
-            .unwrap(),
-    )
+    Arc::new(TaskOptions::new(user_task).data(vm_space).build().unwrap())
 }
 
-fn handle_syscall(user_context: &mut UserContext, user_space: &UserSpace) {
+fn create_user_context() -> UserContext {
+    // The user-space CPU states can be initialized
+    // to arbitrary values via the `UserContext`
+    // abstraction.
+    let mut user_ctx = UserContext::default();
+    const ENTRY_POINT: Vaddr = 0x0040_1000; // The entry point for statically-linked executable
+    user_ctx.set_rip(ENTRY_POINT);
+    user_ctx
+}
+
+fn handle_syscall(user_context: &mut UserContext, vm_space: &VmSpace) {
     const SYS_WRITE: usize = 1;
     const SYS_EXIT: usize = 60;
 
@@ -123,8 +116,7 @@ fn handle_syscall(user_context: &mut UserContext, user_space: &UserSpace) {
                 let mut buf = vec![0u8; buf_len];
                 // Copy data from the user space without
                 // unsafe pointer dereferencing.
-                let current_vm_space = user_space.vm_space();
-                let mut reader = current_vm_space.reader(buf_addr, buf_len).unwrap();
+                let mut reader = vm_space.reader(buf_addr, buf_len).unwrap();
                 reader
                     .read_fallible(&mut VmWriter::from(&mut buf as &mut [u8]))
                     .unwrap();