diff --git a/README.md b/README.md
index fc2edc7..c46298b 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,8 @@ slowly porting from rust.
 `./qemu.sh monitor`  
 `./qemu.sh gdb`  
 
-### todo
+# Notes
 
-- recycling allocator that wraps the bump allocator
+## interrupts
+
+`interrupt` -> `idt[n]` -> `isrN` -> `isrDispatch` -> `handlers[n]` (default `unhandled()`)
diff --git a/build.zig b/build.zig
index b37b877..f13c969 100644
--- a/build.zig
+++ b/build.zig
@@ -2,7 +2,7 @@ const Builder = @import("std").build.Builder;
 const builtin = @import("builtin");
 
 pub fn build(b: *Builder) void {
-    const kernel = b.addExecutable("bzImage", "src/arch/x86/main.zig");
+    const kernel = b.addExecutable("kernel", "src/arch/x86/main.zig");
     kernel.addPackagePath("kernel", "src/index.zig");
     kernel.addPackagePath("arch", "src/arch/x86/lib/index.zig");
     kernel.setOutputDir("build");
@@ -10,6 +10,7 @@ pub fn build(b: *Builder) void {
     kernel.addAssemblyFile("src/arch/x86/_start.s");
     kernel.addAssemblyFile("src/arch/x86/gdt.s");
     kernel.addAssemblyFile("src/arch/x86/isr.s");
+    kernel.addAssemblyFile("src/arch/x86/paging.s");
 
     kernel.setBuildMode(b.standardReleaseOptions());
     kernel.setTarget(builtin.Arch.i386, builtin.Os.freestanding, builtin.Abi.none);
diff --git a/qemu.sh b/qemu.sh
index d989ffd..5291745 100755
--- a/qemu.sh
+++ b/qemu.sh
@@ -1,7 +1,7 @@
 QEMU_SOCKET=/tmp/qemu.sock
 QEMU_MONITOR="socat - UNIX-CONNECT:${QEMU_SOCKET}"
 QEMU_GDB_PORT=4242
-KERNEL=build/bzImage
+KERNEL=build/kernel
 
 start() {
     sudo pkill -9 qemu
@@ -10,11 +10,11 @@ start() {
         -monitor unix:${QEMU_SOCKET},server,nowait \
         -enable-kvm \
         -m 1337M \
-        -display curses \
+        -curses \
         -serial mon:stdio \
         -append "Hello" \
-        -device virtio-net,netdev=network0 -netdev tap,id=network0,ifname=tap0,script=no,downscript=no \
         -kernel ${KERNEL}
+        # -device virtio-net,netdev=network0 -netdev tap,id=network0,ifname=tap0,script=no,downscript=no \
 	# build/kernel.iso
         "$@"
 }
diff --git a/src/arch/x86/gdt.zig b/src/arch/x86/gdt.zig
index ec1c08a..5974038 100644
--- a/src/arch/x86/gdt.zig
+++ b/src/arch/x86/gdt.zig
@@ -72,7 +72,7 @@ fn makeEntry(base: usize, limit: usize, access: u8, flags: u4) GDTEntry {
 }
 
 // Fill in the GDT.
-var gdt align(4) = []GDTEntry{
+var gdt align(4) = [_]GDTEntry{
     makeEntry(0, 0, 0, 0),
     makeEntry(0, 0xFFFFF, KERNEL | CODE, PROTECTED | BLOCKS_4K),
     makeEntry(0, 0xFFFFF, KERNEL | DATA, PROTECTED | BLOCKS_4K),
@@ -92,7 +92,7 @@ var tss = TSS{
     .unused1 = 0,
     .esp0 = undefined,
     .ss0 = KERNEL_DATA,
-    .unused2 = []u32{0} ** 22,
+    .unused2 = [_]u32{0} ** 22,
     .unused3 = 0,
     .iomap_base = @sizeOf(TSS),
 };
diff --git a/src/arch/x86/idt.zig b/src/arch/x86/idt.zig
index ecd2bd5..f06a0b1 100644
--- a/src/arch/x86/idt.zig
+++ b/src/arch/x86/idt.zig
@@ -1,4 +1,5 @@
 // https://wiki.osdev.org/IDT
+usingnamespace @import("../../vga.zig");
 const x86 = @import("lib/index.zig");
 const interrupt = @import("interrupt.zig");
 const gdt = @import("gdt.zig");
@@ -47,12 +48,18 @@ pub fn setGate(n: u8, flags: u8, offset: extern fn () void) void {
     idt[n].flags = flags;
     idt[n].zero = 0;
     idt[n].selector = gdt.KERNEL_CODE;
+    println("offset: 0x{x}", @ptrToInt(offset));
+    println("low   : 0x{x}", idt[n].offset_low);
+    println("high  : 0x{x}", idt[n].offset_high);
 }
 
 ////
 // Initialize the Interrupt Descriptor Table.
 //
 pub fn initialize() void {
+    // configure PIC and set ISRs
     interrupt.initialize();
+
+    // load IDT
     x86.lidt(@ptrToInt(&idtr));
 }
diff --git a/src/arch/x86/interrupt.zig b/src/arch/x86/interrupt.zig
index c7e2912..068bb30 100644
--- a/src/arch/x86/interrupt.zig
+++ b/src/arch/x86/interrupt.zig
@@ -1,5 +1,6 @@
 const x86 = @import("lib/index.zig");
 const isr = @import("isr.zig");
+const println = @import("../../vga.zig").println;
 
 // PIC ports.
 const PIC1_CMD = 0x20;
@@ -31,11 +32,11 @@ var handlers = [_]fn () void{unhandled} ** 48;
 
 fn unhandled() noreturn {
     const n = isr.context.interrupt_n;
-    // if (n >= IRQ_0) {
-    //     tty.panic("unhandled IRQ number {d}", n - IRQ_0);
-    // } else {
-    //     tty.panic("unhandled exception number {d}", n);
-    // }
+    if (n < IRQ_0) {
+        println("unhandled exception number {d}", n);
+    } else {
+        println("unhandled IRQ number {d} (intr {d})", n - IRQ_0, n);
+    }
     x86.hang();
 }
 
@@ -177,6 +178,7 @@ pub fn maskIRQ(irq: u8, mask: bool) void {
     } else {
         x86.outb(port, old & ~(u8(1) << shift));
     }
+    const new = x86.inb(port); // Retrieve the current mask.
 }
 
 ////
diff --git a/src/arch/x86/isr.zig b/src/arch/x86/isr.zig
index 68256c9..90abf13 100644
--- a/src/arch/x86/isr.zig
+++ b/src/arch/x86/isr.zig
@@ -135,24 +135,24 @@ pub fn install() void {
     idt.setGate(30, idt.INTERRUPT_GATE, isr30);
     idt.setGate(31, idt.INTERRUPT_GATE, isr31);
 
-    // // IRQs.
+    // IRQs.
     idt.setGate(32, idt.INTERRUPT_GATE, isr32);
     idt.setGate(33, idt.INTERRUPT_GATE, isr33);
-    // idt.setGate(34, idt.INTERRUPT_GATE, isr34);
-    // idt.setGate(35, idt.INTERRUPT_GATE, isr35);
-    // idt.setGate(36, idt.INTERRUPT_GATE, isr36);
-    // idt.setGate(37, idt.INTERRUPT_GATE, isr37);
-    // idt.setGate(38, idt.INTERRUPT_GATE, isr38);
-    // idt.setGate(39, idt.INTERRUPT_GATE, isr39);
-    // idt.setGate(40, idt.INTERRUPT_GATE, isr40);
-    // idt.setGate(41, idt.INTERRUPT_GATE, isr41);
-    // idt.setGate(42, idt.INTERRUPT_GATE, isr42);
-    // idt.setGate(43, idt.INTERRUPT_GATE, isr43);
-    // idt.setGate(44, idt.INTERRUPT_GATE, isr44);
-    // idt.setGate(45, idt.INTERRUPT_GATE, isr45);
-    // idt.setGate(46, idt.INTERRUPT_GATE, isr46);
-    // idt.setGate(47, idt.INTERRUPT_GATE, isr47);
+    idt.setGate(34, idt.INTERRUPT_GATE, isr34);
+    idt.setGate(35, idt.INTERRUPT_GATE, isr35);
+    idt.setGate(36, idt.INTERRUPT_GATE, isr36);
+    idt.setGate(37, idt.INTERRUPT_GATE, isr37);
+    idt.setGate(38, idt.INTERRUPT_GATE, isr38);
+    idt.setGate(39, idt.INTERRUPT_GATE, isr39);
+    idt.setGate(40, idt.INTERRUPT_GATE, isr40);
+    idt.setGate(41, idt.INTERRUPT_GATE, isr41);
+    idt.setGate(42, idt.INTERRUPT_GATE, isr42);
+    idt.setGate(43, idt.INTERRUPT_GATE, isr43);
+    idt.setGate(44, idt.INTERRUPT_GATE, isr44);
+    idt.setGate(45, idt.INTERRUPT_GATE, isr45);
+    idt.setGate(46, idt.INTERRUPT_GATE, isr46);
+    idt.setGate(47, idt.INTERRUPT_GATE, isr47);
 
-    // // Syscalls.
-    // idt.setGate(128, idt.SYSCALL_GATE, isr128);
+    // Syscalls.
+    idt.setGate(128, idt.SYSCALL_GATE, isr128);
 }
diff --git a/src/arch/x86/lib/instructions.zig b/src/arch/x86/lib/instructions.zig
index 97787d4..99d302d 100644
--- a/src/arch/x86/lib/instructions.zig
+++ b/src/arch/x86/lib/instructions.zig
@@ -24,6 +24,9 @@ pub inline fn hang() noreturn {
 pub inline fn sti() void {
     asm volatile ("sti");
 }
+pub inline fn int3() void {
+    asm volatile ("int3");
+}
 
 ////
 // Load a new Interrupt Descriptor Table.
diff --git a/src/arch/x86/linker.ld b/src/arch/x86/linker.ld
index d90c28b..dabb1b9 100644
--- a/src/arch/x86/linker.ld
+++ b/src/arch/x86/linker.ld
@@ -8,7 +8,8 @@ SECTIONS {
 	. = 0xb8000;
 	. += 80 * 25 * 2;
 
-	. = 0x100000;
+    /* lower half kernel */
+	. = 0x10000;
 
 	/* ensure that the multiboot header is at the beginning */
 	.multiboot :
@@ -67,16 +68,4 @@ SECTIONS {
 		*(.bss .bss.*)
 		. = ALIGN(4K);
 	}
-
-	/* .stab : */
-	/* { */
-	/* 	KEEP(*(.stab)) */
-	/* 	. = ALIGN(4K); */
-	/* } */
-
-	/* .stabstr : */
-	/* { */
-	/* 	KEEP(*(.stabstr)) */
-	/* 	. = ALIGN(4K); */
-	/* } */
 }
diff --git a/src/arch/x86/main.zig b/src/arch/x86/main.zig
index 5adcdf4..68b2c56 100644
--- a/src/arch/x86/main.zig
+++ b/src/arch/x86/main.zig
@@ -1,18 +1,37 @@
 usingnamespace @import("kernel").main;
 usingnamespace @import("kernel").multiboot;
+const console = @import("../console.zig");
+const println = @import("../../vga.zig").println;
+
 const idt = @import("idt.zig");
-const mem = @import("mem.zig");
+const memory = @import("memory.zig");
+const paging = @import("paging.zig");
 const gdt = @import("gdt.zig");
 const x86 = @import("lib/index.zig");
-const console = @import("../console.zig");
-const printf = @import("../../vga.zig").printf;
 
 /// x86 specific intialization
 /// first entry point (see linker.ld)
 pub fn x86_main(info: *const MultibootInfo) void {
-    var allocator = mem.initialize(info);
+    // set up the physical frame allocator
+    memory.initialize(info);
 
-    // gdt.initialize();
+    println("{}", memory.allocator.allocate(1));
+    // println("{}", memory.allocator.allocate(1));
+    // println("{}", memory.allocator.allocate(1));
+    // println("{}", memory.allocator.allocate(1));
+
+    // setup memory segmentation
+    gdt.initialize();
+
+    // setup interrupts
     idt.initialize();
+
+    // enable interrupts
     x86.sti();
+
+    // set up the virtual page mapper
+    paging.initialize();
+
+    // test breakpoint
+    // x86.int3();
 }
diff --git a/src/arch/x86/mem.zig b/src/arch/x86/memory.zig
similarity index 50%
rename from src/arch/x86/mem.zig
rename to src/arch/x86/memory.zig
index 4c4cd9a..d2a5f41 100644
--- a/src/arch/x86/mem.zig
+++ b/src/arch/x86/memory.zig
@@ -1,41 +1,43 @@
 usingnamespace @import("kernel").multiboot;
+usingnamespace @import("../../vga.zig");
 const assert = @import("std").debug.assert;
-const vga = @import("../../vga.zig");
 const std = @import("std");
-const printf = @import("../../vga.zig").printf;
 
-pub fn initialize(info: *const MultibootInfo) bumpAllocator {
+pub var allocator: bumpAllocator = undefined;
+
+pub fn initialize(info: *const MultibootInfo) void {
     assert((info.flags & MULTIBOOT_INFO_MEMORY) != 0);
     assert((info.flags & MULTIBOOT_INFO_MEM_MAP) != 0);
 
     format_multibootinfo(info);
-    return bumpAllocator.new(info);
+    allocator = bumpAllocator.new(info);
 }
 
-pub fn format_multibootentry(entry: *MultibootMMapEntry) void {
+fn format_multibootentry(entry: *MultibootMMapEntry) void {
     if (entry.type == MULTIBOOT_MEMORY_AVAILABLE) {
-        vga.printf("AVAILABLE: ");
+        print("    AVAILABLE: ");
     } else {
-        vga.printf("NOT AVAILABLE: ");
+        print("NOT AVAILABLE: ");
     }
-    vga.printf("{x} ", entry.addr);
+    print("{x} ", entry.addr);
     if (entry.len / (1024 * 1024) > 0) {
-        vga.printf("({} MB)\n", entry.len / (1024 * 1024));
+        println("({} MB)", entry.len / (1024 * 1024));
     } else {
-        vga.printf("({} kB)\n", entry.len / (1024));
+        println("({} kB)", entry.len / (1024));
     }
 }
 
-pub fn format_multibootinfo(info: *const MultibootInfo) void {
+fn format_multibootinfo(info: *const MultibootInfo) void {
     var cmdline_ptr = @intToPtr([*c]const u8, info.cmdline);
     var cmdline = @ptrCast([*c]const u8, cmdline_ptr);
     // var cmdline = std.cstr.toSliceConst(info.cmdline);
-    vga.printf("lower: {x}\n", info.mem_lower);
-    vga.printf("upper: {x}\n", info.mem_upper);
-    vga.printf("mmap_l: {}\n", info.mmap_length);
-    vga.printf("mmap_a: {x}\n", info.mmap_addr);
-    vga.printf("cmdline: {x}\n", cmdline_ptr);
-    vga.printf("cmdline: {}\n", cmdline);
+    println("flags: {b}", info.flags);
+    println("lower: {x}", info.mem_lower);
+    println("upper: {x}", info.mem_upper);
+    println("mmap_l: {}", info.mmap_length);
+    println("mmap_a: {x}", info.mmap_addr);
+    println("cmdline: {x}", cmdline_ptr);
+    println("cmdline: {}", cmdline);
 
     var map: usize = info.mmap_addr;
     while (map < info.mmap_addr + info.mmap_length) {
@@ -47,22 +49,21 @@ pub fn format_multibootinfo(info: *const MultibootInfo) void {
 
 // returns each available physical frame one by one in order
 pub const bumpAllocator = struct {
-    next_free_frame: physFrame,
+    next_free_frame: PhysFrame,
     current_area: ?*MultibootMMapEntry,
     info: *const MultibootInfo,
 
     pub fn new(info: *const MultibootInfo) bumpAllocator {
         const first_area = @intToPtr(*MultibootMMapEntry, info.mmap_addr);
-        var allocator = bumpAllocator{
+        var allocato = bumpAllocator{
             .current_area = first_area,
-            .next_free_frame = physFrame.from_addr(first_area.addr),
+            .next_free_frame = PhysFrame.from_addr(@intCast(u32, first_area.addr)),
             .info = info,
         };
-        // allocator.choose_next_area();
-        return allocator;
+        return allocato;
     }
 
-    pub fn allocate(self: var, count: u64) ?physFrame {
+    pub fn allocate(self: var, count: u32) ?PhysFrame {
         if (count == 0) {
             return null;
         }
@@ -73,10 +74,15 @@ pub const bumpAllocator = struct {
             self.choose_next_area();
             return self.allocate(count);
         }
+        // <4MB identity mapped kernel, lazy trick
+        if (PhysFrame.start_addr(self.next_free_frame) < 0x400000) {
+            self.next_free_frame.number += 1;
+            return self.allocate(count);
+        }
 
         const start_frame = self.next_free_frame;
         const end_frame = self.next_free_frame.add(count - 1);
-        const current_area_last_frame = physFrame.from_addr(self.current_area.?.addr + self.current_area.?.len);
+        const current_area_last_frame = PhysFrame.from_addr(@intCast(u32, self.current_area.?.addr + self.current_area.?.len));
         if (end_frame.number > current_area_last_frame.number) {
             self.choose_next_area();
             return self.allocate(count);
@@ -86,72 +92,33 @@ pub const bumpAllocator = struct {
     }
 
     pub fn choose_next_area(self: var) void {
-        printf("choosing next area\n");
+        println("choosing next area");
         const current = self.current_area.?;
         var next_area = @ptrToInt(current) + current.size + @sizeOf(@typeOf(current));
         if (next_area >= self.info.mmap_addr + self.info.mmap_length) {
             self.current_area = null;
         } else {
-            format_multibootentry(self.current_area.?);
             self.current_area = @intToPtr(*MultibootMMapEntry, next_area);
             format_multibootentry(self.current_area.?);
-            self.next_free_frame = physFrame.from_addr(self.current_area.?.addr);
+            self.next_free_frame = PhysFrame.from_addr(@intCast(u32, self.current_area.?.addr));
         }
     }
 };
 
 pub const PAGE_SIZE = 4096;
 
-pub const physFrame = struct {
-    number: u64,
+pub const PhysFrame = struct {
+    number: u32,
 
-    pub fn from_addr(addr: u64) physFrame {
-        return physFrame{ .number = @divTrunc(addr, PAGE_SIZE) };
+    pub fn from_addr(addr: u32) PhysFrame {
+        return PhysFrame{ .number = @divTrunc(addr, PAGE_SIZE) };
     }
 
-    pub fn add(self: physFrame, count: u64) physFrame {
-        return physFrame{ .number = self.number + count };
+    pub fn add(self: PhysFrame, count: u32) PhysFrame {
+        return PhysFrame{ .number = self.number + count };
     }
 
-    pub fn start_addr(self: physFrame) u64 {
+    pub fn start_addr(self: PhysFrame) u32 {
         return (self.number * PAGE_SIZE);
     }
 };
-
-const PageDirectory = packed struct {
-    entries: [1024]PageDirectoryEntry,
-};
-
-const PageDirectoryEntry = packed struct {
-    address: u21,
-    available: u2,
-    ignored: u1,
-    size: u1,
-    zero: u1,
-    accessed: u1,
-    cache_disabled: u1,
-    write_through: u1,
-    user: u1,
-    writeable: u1,
-    present: u1,
-};
-
-const PageTable = packed struct {
-    entries: [1024]PageTableEntry,
-};
-
-const PageTableEntry = packed struct {
-    address: u21,
-    available: u2,
-    global: u1,
-    zero: u1,
-    dirty: u1,
-    accessed: u1,
-    cache_disabled: u1,
-    write_through: u1,
-    user: u1,
-    writeable: u1,
-    present: u1,
-};
-
-// assert(@sizeOf(PageTableEntry) == 32);
diff --git a/src/arch/x86/paging.s b/src/arch/x86/paging.s
new file mode 100644
index 0000000..c164a28
--- /dev/null
+++ b/src/arch/x86/paging.s
@@ -0,0 +1,24 @@
+.type setupPaging, @function
+.global setupPaging
+
+////
+// Enable the paging system.
+//
+// Arguments:
+//     phys_pd: Physical pointer to the page directory.
+//
+setupPaging:
+  mov +4(%esp), %eax  // Fetch the phys_pd parameter.
+  mov %eax, %cr3      // Point CR3 to the page directory.
+
+  // Enable Page Size Extension and Page Global.
+  mov %cr4, %eax
+  or $0b00010000, %eax
+  mov %eax, %cr4
+
+  // Enable Paging.
+  mov %cr0, %eax
+  or $(1 << 31), %eax
+  mov %eax, %cr0
+
+  ret
diff --git a/src/arch/x86/paging.zig b/src/arch/x86/paging.zig
new file mode 100644
index 0000000..545456f
--- /dev/null
+++ b/src/arch/x86/paging.zig
@@ -0,0 +1,89 @@
+const x86 = @import("lib/index.zig");
+const allocator = @import("memory.zig").allocator;
+const assert = @import("std").debug.assert;
+const println = @import("../../vga.zig").println;
+
+extern fn setupPaging(phys_pd: usize) void;
+
+pub var mapper: Mapper = undefined;
+pub const PAGE_SIZE = 4096;
+
+pub fn initialize() void {
+    const empty_page = PageDirectoryEntry{};
+    // var p2 = allocator.allocate(1);
+    var p2 = [_]PageDirectoryEntry{empty_page} ** 1024;
+    // var p2 = [_]u32{0} ** 1024;
+
+    // identity map 0 -> 4MB
+    p2[0].pageTable = 0x0;
+    p2[0].present = true;
+    p2[0].read_write = true;
+    p2[0].huge = true;
+    // p2[0] = @bitReverse(u32, 0b10000011);
+
+    println("p2[0] {b}", p2[0]);
+    println("p2[0] {b}", @bitCast(u32, p2[0]));
+    // x86.hang();
+    // paging.s
+    // setupPaging(@ptrToInt(&p2));
+
+    // mapper = Mapper{
+    //     .p2 = p2,
+    // };
+    const addr = mapper.translate(0xfffff000);
+}
+
+const builtin = @import("builtin");
+const Mapper = struct {
+    p2: PageDirectory,
+
+    // virt to phys
+    pub fn translate(self: Mapper, virt: u32) ?u32 {
+        const map = @bitCast(VirtAddr, virt);
+        println("{}", builtin.endian);
+        println("virt {x} -> {}-{}-{x}", virt, map.page_directory, map.page_table, map.offset);
+        return null;
+    }
+};
+
+pub const VirtAddr = packed struct {
+    page_directory: u10,
+    page_table: u10,
+    offset: u12,
+};
+
+pub const PageDirectoryEntry = packed struct {
+    pageTable: u20 = 0,
+    available: u3 = 0,
+    ignored: bool = false,
+    huge: bool = false,
+    zero: bool = false,
+    accessed: bool = false,
+    cache_disabled: bool = false,
+    write_thru: bool = false,
+    supervisor: bool = false,
+    read_write: bool = false,
+    present: bool = false,
+};
+
+pub const PageTableEntry = packed struct {
+    addr: u20 = 0,
+    available: u3 = 0,
+    global: bool = false,
+    zero: bool = false,
+    dirty: bool = false,
+    accessed: bool = false,
+    cache_disabled: bool = false,
+    write_thru: bool = false,
+    supervisor: bool = false,
+    read_write: bool = false,
+    present: bool = false,
+};
+
+pub const PageTable = [1024]PageTableEntry;
+pub const PageDirectory = [1024]PageDirectoryEntry;
+
+comptime {
+    assert(@sizeOf(PageDirectoryEntry) == 4); //32 bits
+    assert(@sizeOf(PageTableEntry) == 4); //32 bits
+}
diff --git a/src/console.zig b/src/console.zig
index 1ee615e..7ea8291 100644
--- a/src/console.zig
+++ b/src/console.zig
@@ -33,7 +33,7 @@ pub fn keypress(char: u8) void {
 }
 
 pub fn initialize() void {
-    vga.clear();
-    // vga.writeString("> ");
+    // vga.clear();
     interrupt.registerIRQ(1, ps2.keyboard_handler);
+    vga.writeString("> ");
 }
diff --git a/src/main.zig b/src/main.zig
index fc192d0..5f02270 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -9,17 +9,18 @@ const assert = @import("std").debug.assert;
 // arch independant initialization
 export fn kmain(magic: u32, info: *const MultibootInfo) noreturn {
     assert(magic == MULTIBOOT_BOOTLOADER_MAGIC);
-    console.initialize();
-
-    printf("--- hello x86_main ---\n");
 
+    println("--- x86 initialization ---");
     x86.x86_main(info);
 
     // pagefault_test(0xfeffc000);
 
-    printf("\n--- arch indepent boot ---\n");
+    println("--- core initialization ---");
+    console.initialize();
 
-    while (true) {}
+    while (true) {
+        asm volatile ("hlt");
+    }
 }
 
 fn pagefault_test(addr: u32) void {
diff --git a/src/multiboot.zig b/src/multiboot.zig
index d2630d0..2f217a3 100644
--- a/src/multiboot.zig
+++ b/src/multiboot.zig
@@ -13,29 +13,46 @@ pub const MULTIBOOT_BOOTLOADER_MAGIC = 0x2BADB002;
 pub const MULTIBOOT_INFO_MEMORY      = 0x00000001;
 // Is there a full memory map?
 pub const MULTIBOOT_INFO_MEM_MAP     = 0x00000040;
+
 // System information structure passed by the bootloader.
 pub const MultibootInfo = packed struct {
     // Multiboot info version number.
     flags: u32,
 
     // Available memory from BIOS.
+    // present if flags[0]
     mem_lower: u32,
     mem_upper: u32,
 
-    // "root" partition.
+    // present if flags[1]
     boot_device: u32,
 
-    // Kernel command line.
+    // present if flags[2]
     cmdline: u32,
 
     // Boot-Module list.
     mods_count: u32,
     mods_addr:  u32,
 
-    // TODO: use the real types here.
-    u: u128,
+    syms: extern union {
+        // present if flags[4]
+        nlist: extern struct {
+           tabsize: u32,
+           strsize: u32,
+           addr: u32,
+           _reserved: u32,
+        },
+        // present if flags[5]
+        shdr: extern struct {
+           num: u32,
+           size: u32,
+           addr: u32,
+           shndx: u32,
+        },
+    },
 
     // Memory Mapping buffer.
+    // present if flags[6]
     mmap_length: u32,
     mmap_addr:   u32,
 
@@ -112,16 +129,22 @@ const MultibootHeader = packed struct {
     magic:    u32,  // Must be equal to header magic number.
     flags:    u32,  // Feature flags.
     checksum: u32,  // Above fields plus this one must equal 0 mod 2^32.
+    // following fields are used if flag bit 16 is specified
+    header_addr: u32 = 0,
+    load_addr: u32 = 0,
+    load_end_addr: u32 = 0,
+    bss_end_addr: u32 = 0,
+    entry_addr: u32 = 0,
 };
 // NOTE: this structure is incomplete.
 
 // Place the header at the very beginning of the binary.
 export const multiboot_header align(4) linksection(".multiboot") = multiboot: {
     const MAGIC   = u32(0x1BADB002);  // multiboot magic
-    const ALIGN   = u32(1 << 0);      // Align loaded modules.
+    const ALIGN   = u32(1 << 0);      // Align loaded modules at 4k
     const MEMINFO = u32(1 << 1);      // Receive a memory map from the bootloader.
-    const CMDLINE = u32(1 << 2);      // Receive a cmdline from the bootloader
-    const FLAGS   = ALIGN | MEMINFO | CMDLINE;  // Combine the flags.
+    const ADDR     = u32(1 << 16);    // Load specific addr
+    const FLAGS   = ALIGN | MEMINFO;  // Combine the flags.
 
     break :multiboot MultibootHeader {
         .magic    = MAGIC,
diff --git a/src/pci.zig b/src/pci.zig
index 131e52a..624e0f0 100644
--- a/src/pci.zig
+++ b/src/pci.zig
@@ -2,7 +2,7 @@ const arch = @import("arch/x86/lib/index.zig");
 
 const PCI_CONFIG_ADDRESS = 0xCF8;
 const PCI_CONFIG_DATA = 0xCFC;
-const vga = @import("vga.zig");
+usingnamespace @import("vga.zig");
 
 pub const PciAddress = packed struct {
     offset: u8,
@@ -57,7 +57,7 @@ pub const PciDevice = struct {
     }
 
     pub fn format(self: PciDevice) void {
-        vga.printf("{}:{}.{} {x},{x}: {x} {x}\n", self.bus, self.slot, self.function, self.class, self.subclass, self.vendor, self.device);
+        println("{}:{}.{} {x},{x}: {x} {x}", self.bus, self.slot, self.function, self.class, self.subclass, self.vendor, self.device);
     }
 
     pub fn access(self: PciDevice, offset: u8) void {
diff --git a/src/ps2.zig b/src/ps2.zig
index 57731e2..84aced6 100644
--- a/src/ps2.zig
+++ b/src/ps2.zig
@@ -1,3 +1,4 @@
+usingnamespace @import("vga.zig");
 const x86 = @import("arch/x86/lib/index.zig");
 const console = @import("console.zig");
 
@@ -84,6 +85,7 @@ fn key_isrelease(scancode: u8) bool {
 pub fn keyboard_handler() void {
     const scancode = ps2_scancode();
     const isrelease = key_isrelease(scancode);
+    println("keyboard scancode 0b{b}", scancode);
     if (isrelease) {
         return;
     }
diff --git a/src/vga.zig b/src/vga.zig
index 3a73c71..7b90ede 100644
--- a/src/vga.zig
+++ b/src/vga.zig
@@ -56,10 +56,14 @@ pub fn disableCursor() void {
 }
 
 const Errors = error{};
-pub fn printf(comptime format: []const u8, args: ...) void {
+pub fn print(comptime format: []const u8, args: ...) void {
     var a = std.fmt.format({}, Errors, printCallback, format, args);
 }
 
+pub fn println(comptime format: []const u8, args: ...) void {
+    var a = std.fmt.format({}, Errors, printCallback, format ++ "\n", args);
+}
+
 fn printCallback(context: void, string: []const u8) Errors!void {
     vga.writeString(string);
 }