diff --git a/arch/x86_64/src/memory/area_frame_allocator.rs b/arch/x86_64/src/memory/area_frame_allocator.rs
index 15f21a2..54088d2 100644
--- a/arch/x86_64/src/memory/area_frame_allocator.rs
+++ b/arch/x86_64/src/memory/area_frame_allocator.rs
@@ -43,11 +43,12 @@ impl AreaFrameAllocator {
 }
 
 impl FrameAllocator for AreaFrameAllocator {
-    fn allocate_frame(&mut self) -> Option<Frame> {
+    fn allocate_frames(&mut self, count: usize) -> Option<Frame> {
         if let Some(area) = self.current_area {
             // "Clone" the frame to return it if it's free. Frame doesn't
             // implement Clone, but we can construct an identical frame.
-            let frame = Frame{ number: self.next_free_frame.number };
+            let start_frame = Frame{ number: self.next_free_frame.number };
+            let end_frame = Frame { number: self.next_free_frame.number + count };
 
             // the last frame of the current area
             let current_area_last_frame = {
@@ -55,27 +56,28 @@ impl FrameAllocator for AreaFrameAllocator {
                 Frame::containing_address(PhysicalAddress::new(address as usize))
             };
 
-            if frame > current_area_last_frame {
+            if end_frame > current_area_last_frame {
                 // all frames of current area are used, switch to next area
                 self.choose_next_area();
-            } else if frame >= self.kernel_start && frame <= self.kernel_end {
+            } else if (start_frame >= self.kernel_start && start_frame <= self.kernel_end)
+                    || (end_frame >= self.kernel_start && end_frame <= self.kernel_end) {
                 // `frame` is used by the kernel
                 self.next_free_frame = Frame {
                     number: self.kernel_end.number + 1
                 };
             } else {
                 // frame is unused, increment `next_free_frame` and return it
-                self.next_free_frame.number += 1;
-                return Some(frame);
+                self.next_free_frame.number += count;
+                return Some(start_frame);
             }
             // `frame` was not valid, try it again with the updated `next_free_frame`
-            self.allocate_frame()
+            self.allocate_frames(count)
         } else {
             None // no free frames left
         }
     }
 
-    fn deallocate_frame(&mut self, frame: Frame) {
+    fn deallocate_frames(&mut self, frame: Frame, count: usize) {
         //panic!("AreaFrameAllocator::deallocate_frame: not supported: {:?}", frame);
     }
 }
diff --git a/arch/x86_64/src/memory/mod.rs b/arch/x86_64/src/memory/mod.rs
index 02c6c2b..f7f5048 100644
--- a/arch/x86_64/src/memory/mod.rs
+++ b/arch/x86_64/src/memory/mod.rs
@@ -69,17 +69,27 @@ pub unsafe fn init(kernel_start: usize, kernel_end: usize) {
 
 /// Allocate a frame
 pub fn allocate_frame() -> Option<Frame> {
+    allocate_frames(1)
+}
+
+/// Deallocate a frame
+pub fn deallocate_frame(frame: Frame) {
+    deallocate_frames(frame, 1)
+}
+
+/// Allocate a range of frames
+pub fn allocate_frames(count: usize) -> Option<Frame> {
     if let Some(ref mut allocator) = *ALLOCATOR.lock() {
-        allocator.allocate_frame()
+        allocator.allocate_frames(count)
     } else {
         panic!("frame allocator not initialized");
     }
 }
 
-/// Deallocate a frame
-pub fn deallocate_frame(frame: Frame) {
+/// Deallocate a range of frames frame
+pub fn deallocate_frames(frame: Frame, count: usize) {
     if let Some(ref mut allocator) = *ALLOCATOR.lock() {
-        allocator.deallocate_frame(frame)
+        allocator.deallocate_frames(frame, count)
     } else {
         panic!("frame allocator not initialized");
     }
@@ -151,6 +161,6 @@ impl Iterator for FrameIter {
 }
 
 pub trait FrameAllocator {
-    fn allocate_frame(&mut self) -> Option<Frame>;
-    fn deallocate_frame(&mut self, frame: Frame);
+    fn allocate_frames(&mut self, size: usize) -> Option<Frame>;
+    fn deallocate_frames(&mut self, frame: Frame, size: usize);
 }
diff --git a/drivers/ahcid/Cargo.toml b/drivers/ahcid/Cargo.toml
new file mode 100644
index 0000000..2bc8fa8
--- /dev/null
+++ b/drivers/ahcid/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "ahcid"
+version = "0.1.0"
+
+[dependencies]
+bitflags = "*"
+io = { path = "../io/" }
+spin = "*"
+syscall = { path = "../../syscall/" }
diff --git a/drivers/ahcid/src/ahci/fis.rs b/drivers/ahcid/src/ahci/fis.rs
new file mode 100644
index 0000000..7dbe33c
--- /dev/null
+++ b/drivers/ahcid/src/ahci/fis.rs
@@ -0,0 +1,155 @@
+use io::Mmio;
+
+#[repr(u8)]
+pub enum FisType {
+    /// Register FIS - host to device
+    RegH2D = 0x27,
+    /// Register FIS - device to host
+    RegD2H = 0x34,
+    /// DMA activate FIS - device to host
+    DmaAct = 0x39,
+    /// DMA setup FIS - bidirectional
+    DmaSetup = 0x41,
+    /// Data FIS - bidirectional
+    Data = 0x46,
+    /// BIST activate FIS - bidirectional
+    Bist = 0x58,
+    /// PIO setup FIS - device to host
+    PioSetup = 0x5F,
+    /// Set device bits FIS - device to host
+    DevBits = 0xA1
+}
+
+#[repr(packed)]
+pub struct FisRegH2D {
+    // DWORD 0
+    pub fis_type: Mmio<u8>, // FIS_TYPE_REG_H2D
+
+    pub pm: Mmio<u8>, // Port multiplier, 1: Command, 0: Control
+
+    pub command: Mmio<u8>, // Command register
+    pub featurel: Mmio<u8>, // Feature register, 7:0
+
+    // DWORD 1
+    pub lba0: Mmio<u8>, // LBA low register, 7:0
+    pub lba1: Mmio<u8>, // LBA mid register, 15:8
+    pub lba2: Mmio<u8>, // LBA high register, 23:16
+    pub device: Mmio<u8>, // Device register
+
+    // DWORD 2
+    pub lba3: Mmio<u8>, // LBA register, 31:24
+    pub lba4: Mmio<u8>, // LBA register, 39:32
+    pub lba5: Mmio<u8>, // LBA register, 47:40
+    pub featureh: Mmio<u8>, // Feature register, 15:8
+
+    // DWORD 3
+    pub countl: Mmio<u8>, // Count register, 7:0
+    pub counth: Mmio<u8>, // Count register, 15:8
+    pub icc: Mmio<u8>, // Isochronous command completion
+    pub control: Mmio<u8>, // Control register
+
+    // DWORD 4
+    pub rsv1: [Mmio<u8>; 4], // Reserved
+}
+
+#[repr(packed)]
+pub struct FisRegD2H {
+    // DWORD 0
+    pub fis_type: Mmio<u8>, // FIS_TYPE_REG_D2H
+
+    pub pm: Mmio<u8>, // Port multiplier, Interrupt bit: 2
+
+    pub status: Mmio<u8>, // Status register
+    pub error: Mmio<u8>, // Error register
+
+    // DWORD 1
+    pub lba0: Mmio<u8>, // LBA low register, 7:0
+    pub lba1: Mmio<u8>, // LBA mid register, 15:8
+    pub lba2: Mmio<u8>, // LBA high register, 23:16
+    pub device: Mmio<u8>, // Device register
+
+    // DWORD 2
+    pub lba3: Mmio<u8>, // LBA register, 31:24
+    pub lba4: Mmio<u8>, // LBA register, 39:32
+    pub lba5: Mmio<u8>, // LBA register, 47:40
+    pub rsv2: Mmio<u8>, // Reserved
+
+    // DWORD 3
+    pub countl: Mmio<u8>, // Count register, 7:0
+    pub counth: Mmio<u8>, // Count register, 15:8
+    pub rsv3: [Mmio<u8>; 2], // Reserved
+
+    // DWORD 4
+    pub rsv4: [Mmio<u8>; 4], // Reserved
+}
+
+#[repr(packed)]
+pub struct FisData {
+    // DWORD 0
+    pub fis_type: Mmio<u8>, // FIS_TYPE_DATA
+
+    pub pm: Mmio<u8>, // Port multiplier
+
+    pub rsv1: [Mmio<u8>; 2], // Reserved
+
+    // DWORD 1 ~ N
+    pub data: [Mmio<u8>; 252], // Payload
+}
+
+#[repr(packed)]
+pub struct FisPioSetup {
+    // DWORD 0
+    pub fis_type: Mmio<u8>, // FIS_TYPE_PIO_SETUP
+
+    pub pm: Mmio<u8>, // Port multiplier, direction: 4 - device to host, interrupt: 2
+
+    pub status: Mmio<u8>, // Status register
+    pub error: Mmio<u8>, // Error register
+
+    // DWORD 1
+    pub lba0: Mmio<u8>, // LBA low register, 7:0
+    pub lba1: Mmio<u8>, // LBA mid register, 15:8
+    pub lba2: Mmio<u8>, // LBA high register, 23:16
+    pub device: Mmio<u8>, // Device register
+
+    // DWORD 2
+    pub lba3: Mmio<u8>, // LBA register, 31:24
+    pub lba4: Mmio<u8>, // LBA register, 39:32
+    pub lba5: Mmio<u8>, // LBA register, 47:40
+    pub rsv2: Mmio<u8>, // Reserved
+
+    // DWORD 3
+    pub countl: Mmio<u8>, // Count register, 7:0
+    pub counth: Mmio<u8>, // Count register, 15:8
+    pub rsv3: Mmio<u8>, // Reserved
+    pub e_status: Mmio<u8>, // New value of status register
+
+    // DWORD 4
+    pub tc: Mmio<u16>, // Transfer count
+    pub rsv4: [Mmio<u8>; 2], // Reserved
+}
+
+#[repr(packed)]
+pub struct FisDmaSetup {
+    // DWORD 0
+    pub fis_type: Mmio<u8>, // FIS_TYPE_DMA_SETUP
+
+    pub pm: Mmio<u8>, // Port multiplier, direction: 4 - device to host, interrupt: 2, auto-activate: 1
+
+    pub rsv1: [Mmio<u8>; 2], // Reserved
+
+    // DWORD 1&2
+    pub dma_buffer_id: Mmio<u64>, /* DMA Buffer Identifier. Used to Identify DMA buffer in host memory. SATA Spec says host specific and not in Spec. Trying AHCI spec might work. */
+
+    // DWORD 3
+    pub rsv3: Mmio<u32>, // More reserved
+
+    // DWORD 4
+    pub dma_buffer_offset: Mmio<u32>, // Byte offset into buffer. First 2 bits must be 0
+
+    // DWORD 5
+    pub transfer_count: Mmio<u32>, // Number of bytes to transfer. Bit 0 must be 0
+
+    // DWORD 6
+    pub rsv6: Mmio<u32>, // Reserved
+}
diff --git a/drivers/ahcid/src/ahci/hba.rs b/drivers/ahcid/src/ahci/hba.rs
new file mode 100644
index 0000000..f7ca720
--- /dev/null
+++ b/drivers/ahcid/src/ahci/hba.rs
@@ -0,0 +1,393 @@
+use io::{Io, Mmio};
+
+use std::mem::size_of;
+use std::{ptr, u32};
+
+use syscall::{physalloc, physmap, physunmap, virttophys, MAP_WRITE};
+use syscall::error::{Error, Result, EIO};
+
+use super::fis::{FisType, FisRegH2D};
+
+const ATA_CMD_READ_DMA_EXT: u8 = 0x25;
+const ATA_CMD_WRITE_DMA_EXT: u8 = 0x35;
+const ATA_CMD_IDENTIFY: u8 = 0xEC;
+const ATA_DEV_BUSY: u8 = 0x80;
+const ATA_DEV_DRQ: u8 = 0x08;
+
+const HBA_PORT_CMD_CR: u32 = 1 << 15;
+const HBA_PORT_CMD_FR: u32 = 1 << 14;
+const HBA_PORT_CMD_FRE: u32 = 1 << 4;
+const HBA_PORT_CMD_ST: u32 = 1;
+const HBA_PORT_IS_TFES: u32 = 1 << 30;
+const HBA_SSTS_PRESENT: u32 = 0x3;
+const HBA_SIG_ATA: u32 = 0x00000101;
+const HBA_SIG_ATAPI: u32 = 0xEB140101;
+const HBA_SIG_PM: u32 = 0x96690101;
+const HBA_SIG_SEMB: u32 = 0xC33C0101;
+
+#[derive(Debug)]
+pub enum HbaPortType {
+    None,
+    Unknown(u32),
+    SATA,
+    SATAPI,
+    PM,
+    SEMB,
+}
+
+#[repr(packed)]
+pub struct HbaPort {
+    pub clb: Mmio<u64>, // 0x00, command list base address, 1K-byte aligned
+    pub fb: Mmio<u64>, // 0x08, FIS base address, 256-byte aligned
+    pub is: Mmio<u32>, // 0x10, interrupt status
+    pub ie: Mmio<u32>, // 0x14, interrupt enable
+    pub cmd: Mmio<u32>, // 0x18, command and status
+    pub rsv0: Mmio<u32>, // 0x1C, Reserved
+    pub tfd: Mmio<u32>, // 0x20, task file data
+    pub sig: Mmio<u32>, // 0x24, signature
+    pub ssts: Mmio<u32>, // 0x28, SATA status (SCR0:SStatus)
+    pub sctl: Mmio<u32>, // 0x2C, SATA control (SCR2:SControl)
+    pub serr: Mmio<u32>, // 0x30, SATA error (SCR1:SError)
+    pub sact: Mmio<u32>, // 0x34, SATA active (SCR3:SActive)
+    pub ci: Mmio<u32>, // 0x38, command issue
+    pub sntf: Mmio<u32>, // 0x3C, SATA notification (SCR4:SNotification)
+    pub fbs: Mmio<u32>, // 0x40, FIS-based switch control
+    pub rsv1: [Mmio<u32>; 11], // 0x44 ~ 0x6F, Reserved
+    pub vendor: [Mmio<u32>; 4], // 0x70 ~ 0x7F, vendor specific
+}
+
+impl HbaPort {
+    pub fn probe(&self) -> HbaPortType {
+        if self.ssts.readf(HBA_SSTS_PRESENT) {
+            let sig = self.sig.read();
+            match sig {
+                HBA_SIG_ATA => HbaPortType::SATA,
+                HBA_SIG_ATAPI => HbaPortType::SATAPI,
+                HBA_SIG_PM => HbaPortType::PM,
+                HBA_SIG_SEMB => HbaPortType::SEMB,
+                _ => HbaPortType::Unknown(sig),
+            }
+        } else {
+            HbaPortType::None
+        }
+    }
+
+    pub fn init(&mut self) {
+        self.stop();
+
+        let clb_phys = unsafe { physalloc(size_of::<HbaCmdHeader>()).unwrap() };
+        self.clb.write(clb_phys as u64);
+
+        let fb = unsafe { physalloc(256).unwrap() };
+        self.fb.write(fb as u64);
+
+        let clb = unsafe { physmap(clb_phys, size_of::<HbaCmdHeader>(), MAP_WRITE).unwrap() } as *mut HbaCmdHeader;
+        for i in 0..32 {
+            let cmdheader = unsafe { &mut *clb.offset(i) };
+            let ctba = unsafe { physalloc(size_of::<HbaCmdTable>()).unwrap() };
+            cmdheader.ctba.write(ctba as u64);
+            cmdheader.prdtl.write(0);
+        }
+        unsafe { physunmap(clb as usize).unwrap(); }
+
+        self.start();
+    }
+
+    pub unsafe fn identify(&mut self, port: usize) -> Option<u64> {
+        self.is.write(u32::MAX);
+
+        let dest_phys = physalloc(256).unwrap();
+        let dest = physmap(dest_phys, 256, MAP_WRITE).unwrap() as *mut u16;
+
+        if let Some(slot) = self.slot() {
+            {
+                let clb = unsafe { physmap(self.clb.read() as usize, size_of::<HbaCmdHeader>(), MAP_WRITE).unwrap() } as *mut HbaCmdHeader;
+                let cmdheader = &mut *clb.offset(slot as isize);
+                cmdheader.cfl.write(((size_of::<FisRegH2D>() / size_of::<u32>()) as u8));
+                cmdheader.prdtl.write(1);
+
+                let ctba = unsafe { physmap(cmdheader.ctba.read() as usize, size_of::<HbaCmdTable>(), MAP_WRITE).unwrap() } as *mut HbaCmdTable;
+                ptr::write_bytes(ctba as *mut u8, 0, size_of::<HbaCmdTable>());
+                let cmdtbl = &mut *(ctba);
+
+                let prdt_entry = &mut cmdtbl.prdt_entry[0];
+                prdt_entry.dba.write(dest_phys as u64);
+                prdt_entry.dbc.write(512 | 1);
+
+                let cmdfis = &mut *(cmdtbl.cfis.as_ptr() as *mut FisRegH2D);
+
+                cmdfis.fis_type.write(FisType::RegH2D as u8);
+                cmdfis.pm.write(1 << 7);
+                cmdfis.command.write(ATA_CMD_IDENTIFY);
+                cmdfis.device.write(0);
+                cmdfis.countl.write(1);
+                cmdfis.counth.write(0);
+
+                unsafe { physunmap(ctba as usize).unwrap(); }
+                unsafe { physunmap(clb as usize).unwrap(); }
+            }
+
+            while self.tfd.readf((ATA_DEV_BUSY | ATA_DEV_DRQ) as u32) {}
+
+            self.ci.writef(1 << slot, true);
+
+            while self.ci.readf(1 << slot) {
+                if self.is.readf(HBA_PORT_IS_TFES) {
+                    return None;
+                }
+            }
+
+            if self.is.readf(HBA_PORT_IS_TFES) {
+                return None;
+            }
+
+            let mut serial = String::new();
+            for word in 10..20 {
+                let d = *dest.offset(word);
+                let a = ((d >> 8) as u8) as char;
+                if a != '\0' {
+                    serial.push(a);
+                }
+                let b = (d as u8) as char;
+                if b != '\0' {
+                    serial.push(b);
+                }
+            }
+
+            let mut firmware = String::new();
+            for word in 23..27 {
+                let d = *dest.offset(word);
+                let a = ((d >> 8) as u8) as char;
+                if a != '\0' {
+                    firmware.push(a);
+                }
+                let b = (d as u8) as char;
+                if b != '\0' {
+                    firmware.push(b);
+                }
+            }
+
+            let mut model = String::new();
+            for word in 27..47 {
+                let d = *dest.offset(word);
+                let a = ((d >> 8) as u8) as char;
+                if a != '\0' {
+                    model.push(a);
+                }
+                let b = (d as u8) as char;
+                if b != '\0' {
+                    model.push(b);
+                }
+            }
+
+            let mut sectors = (*dest.offset(100) as u64) |
+                              ((*dest.offset(101) as u64) << 16) |
+                              ((*dest.offset(102) as u64) << 32) |
+                              ((*dest.offset(103) as u64) << 48);
+
+            let lba_bits = if sectors == 0 {
+                sectors = (*dest.offset(60) as u64) | ((*dest.offset(61) as u64) << 16);
+                28
+            } else {
+                48
+            };
+
+            println!("   + Port {}: Serial: {} Firmware: {} Model: {} {}-bit LBA Size: {} MB",
+                        port, serial.trim(), firmware.trim(), model.trim(), lba_bits, sectors / 2048);
+
+            Some(sectors * 512)
+        } else {
+            None
+        }
+    }
+
+    pub fn start(&mut self) {
+        while self.cmd.readf(HBA_PORT_CMD_CR) {}
+
+        self.cmd.writef(HBA_PORT_CMD_FRE, true);
+        self.cmd.writef(HBA_PORT_CMD_ST, true);
+    }
+
+    pub fn stop(&mut self) {
+        self.cmd.writef(HBA_PORT_CMD_ST, false);
+
+        while self.cmd.readf(HBA_PORT_CMD_FR | HBA_PORT_CMD_CR) {}
+
+        self.cmd.writef(HBA_PORT_CMD_FRE, false);
+    }
+
+    pub fn slot(&self) -> Option<u32> {
+        let slots = self.sact.read() | self.ci.read();
+        for i in 0..32 {
+            if slots & 1 << i == 0 {
+                return Some(i);
+            }
+        }
+        None
+    }
+
+    pub fn ata_dma_small(&mut self, block: u64, sectors: usize, mut buf: usize, write: bool) -> Result<usize> {
+        if buf >= 0x80000000 {
+            buf -= 0x80000000;
+        }
+
+        // TODO: PRDTL for files larger than 4MB
+        let entries = 1;
+
+        if buf > 0 && sectors > 0 {
+            self.is.write(u32::MAX);
+
+            if let Some(slot) = self.slot() {
+                println!("Slot {}", slot);
+
+                let clb = self.clb.read() as usize;
+                let cmdheader = unsafe { &mut *(clb as *mut HbaCmdHeader).offset(slot as isize) };
+
+                cmdheader.cfl.write(((size_of::<FisRegH2D>() / size_of::<u32>()) as u8));
+                cmdheader.cfl.writef(1 << 6, write);
+
+                cmdheader.prdtl.write(entries);
+
+                let ctba = cmdheader.ctba.read() as usize;
+                unsafe { ptr::write_bytes(ctba as *mut u8, 0, size_of::<HbaCmdTable>()) };
+                let cmdtbl = unsafe { &mut *(ctba as *mut HbaCmdTable) };
+
+                let prdt_entry = &mut cmdtbl.prdt_entry[0];
+                prdt_entry.dba.write(buf as u64);
+                prdt_entry.dbc.write(((sectors * 512) as u32) | 1);
+
+                let cmdfis = unsafe { &mut *(cmdtbl.cfis.as_ptr() as *mut FisRegH2D) };
+
+                cmdfis.fis_type.write(FisType::RegH2D as u8);
+                cmdfis.pm.write(1 << 7);
+                if write {
+                    cmdfis.command.write(ATA_CMD_WRITE_DMA_EXT);
+                } else {
+                    cmdfis.command.write(ATA_CMD_READ_DMA_EXT);
+                }
+
+                cmdfis.lba0.write(block as u8);
+                cmdfis.lba1.write((block >> 8) as u8);
+                cmdfis.lba2.write((block >> 16) as u8);
+
+                cmdfis.device.write(1 << 6);
+
+                cmdfis.lba3.write((block >> 24) as u8);
+                cmdfis.lba4.write((block >> 32) as u8);
+                cmdfis.lba5.write((block >> 40) as u8);
+
+                cmdfis.countl.write(sectors as u8);
+                cmdfis.counth.write((sectors >> 8) as u8);
+
+                println!("Busy Wait");
+                while self.tfd.readf((ATA_DEV_BUSY | ATA_DEV_DRQ) as u32) {}
+
+                self.ci.writef(1 << slot, true);
+
+                println!("Completion Wait");
+                while self.ci.readf(1 << slot) {
+                    if self.is.readf(HBA_PORT_IS_TFES) {
+                        return Err(Error::new(EIO));
+                    }
+                }
+
+                if self.is.readf(HBA_PORT_IS_TFES) {
+                    return Err(Error::new(EIO));
+                }
+
+                Ok(sectors * 512)
+            } else {
+                println!("No Command Slots");
+                Err(Error::new(EIO))
+            }
+        } else {
+            println!("Invalid request");
+            Err(Error::new(EIO))
+        }
+    }
+
+    pub fn ata_dma(&mut self, block: u64, sectors: usize, buf: usize, write: bool) -> Result<usize> {
+        println!("AHCI {:X} DMA BLOCK: {:X} SECTORS: {} BUF: {:X} WRITE: {}", (self as *mut HbaPort) as usize, block, sectors, buf, write);
+
+        if sectors > 0 {
+            let physical_address = try!(unsafe { virttophys(buf) });
+
+            let mut sector: usize = 0;
+            while sectors - sector >= 255 {
+                if let Err(err) = self.ata_dma_small(block + sector as u64, 255, physical_address + sector * 512, write) {
+                    return Err(err);
+                }
+
+                sector += 255;
+            }
+            if sector < sectors {
+                if let Err(err) = self.ata_dma_small(block + sector as u64, sectors - sector, physical_address + sector * 512, write) {
+                    return Err(err);
+                }
+            }
+
+            Ok(sectors * 512)
+        } else {
+            println!("Invalid request");
+            Err(Error::new(EIO))
+        }
+    }
+}
+
+#[repr(packed)]
+pub struct HbaMem {
+    pub cap: Mmio<u32>, // 0x00, Host capability
+    pub ghc: Mmio<u32>, // 0x04, Global host control
+    pub is: Mmio<u32>, // 0x08, Interrupt status
+    pub pi: Mmio<u32>, // 0x0C, Port implemented
+    pub vs: Mmio<u32>, // 0x10, Version
+    pub ccc_ctl: Mmio<u32>, // 0x14, Command completion coalescing control
+    pub ccc_pts: Mmio<u32>, // 0x18, Command completion coalescing ports
+    pub em_loc: Mmio<u32>, // 0x1C, Enclosure management location
+    pub em_ctl: Mmio<u32>, // 0x20, Enclosure management control
+    pub cap2: Mmio<u32>, // 0x24, Host capabilities extended
+    pub bohc: Mmio<u32>, // 0x28, BIOS/OS handoff control and status
+    pub rsv: [Mmio<u8>; 116], // 0x2C - 0x9F, Reserved
+    pub vendor: [Mmio<u8>; 96], // 0xA0 - 0xFF, Vendor specific registers
+    pub ports: [HbaPort; 32], // 0x100 - 0x10FF, Port control registers
+}
+
+#[repr(packed)]
+struct HbaPrdtEntry {
+    dba: Mmio<u64>, // Data base address
+    rsv0: Mmio<u32>, // Reserved
+    dbc: Mmio<u32>, // Byte count, 4M max, interrupt = 1
+}
+
+#[repr(packed)]
+struct HbaCmdTable {
+    // 0x00
+    cfis: [Mmio<u8>; 64], // Command FIS
+
+    // 0x40
+    acmd: [Mmio<u8>; 16], // ATAPI command, 12 or 16 bytes
+
+    // 0x50
+    rsv: [Mmio<u8>; 48], // Reserved
+
+    // 0x80
+    prdt_entry: [HbaPrdtEntry; 65536], // Physical region descriptor table entries, 0 ~ 65535
+}
+
+#[repr(packed)]
+struct HbaCmdHeader {
+    // DW0
+    cfl: Mmio<u8>, /* Command FIS length in DWORDS, 2 ~ 16, atapi: 4, write - host to device: 2, prefetchable: 1 */
+    pm: Mmio<u8>, // Reset - 0x80, bist: 0x40, clear busy on ok: 0x20, port multiplier
+
+    prdtl: Mmio<u16>, // Physical region descriptor table length in entries
+
+    // DW1
+    prdbc: Mmio<u32>, // Physical region descriptor byte count transferred
+
+    // DW2, 3
+    ctba: Mmio<u64>, // Command table descriptor base address
+
+    // DW4 - 7
+    rsv1: [Mmio<u32>; 4], // Reserved
+}
diff --git a/drivers/ahcid/src/ahci/mod.rs b/drivers/ahcid/src/ahci/mod.rs
new file mode 100644
index 0000000..cdf54ca
--- /dev/null
+++ b/drivers/ahcid/src/ahci/mod.rs
@@ -0,0 +1,83 @@
+use io::Io;
+
+use syscall::error::Result;
+
+use self::hba::{HbaMem, HbaPort, HbaPortType};
+
+pub mod fis;
+pub mod hba;
+
+pub struct Ahci;
+
+impl Ahci {
+    pub fn disks(base: usize, irq: u8) -> Vec<AhciDisk> {
+        println!(" + AHCI on: {:X} IRQ: {:X}", base as usize, irq);
+
+        let pi = unsafe { &mut *(base as *mut HbaMem) }.pi.read();
+        let ret: Vec<AhciDisk> = (0..32)
+              .filter(|&i| pi & 1 << i as i32 == 1 << i as i32)
+              .filter_map(|i| {
+                  let mut disk = AhciDisk::new(base, i, irq);
+                  let port_type = disk.port.probe();
+                  println!("{}: {:?}", i, port_type);
+                  match port_type {
+                      HbaPortType::SATA => {
+                          /*
+                          disk.port.init();
+                          if let Some(size) = unsafe { disk.port.identify(i) } {
+                              disk.size = size;
+                              Some(disk)
+                          } else {
+                              None
+                          }
+                          */
+                          None
+                      }
+                      _ => None,
+                  }
+              })
+              .collect();
+
+        ret
+    }
+}
+
+pub struct AhciDisk {
+    port: &'static mut HbaPort,
+    port_index: usize,
+    irq: u8,
+    size: u64,
+}
+
+impl AhciDisk {
+    fn new(base: usize, port_index: usize, irq: u8) -> Self {
+        AhciDisk {
+            port: &mut unsafe { &mut *(base as *mut HbaMem) }.ports[port_index],
+            port_index: port_index,
+            irq: irq,
+            size: 0
+        }
+    }
+
+    fn name(&self) -> String {
+        format!("AHCI Port {}", self.port_index)
+    }
+
+    fn on_irq(&mut self, irq: u8) {
+        if irq == self.irq {
+            //debugln!("AHCI IRQ");
+        }
+    }
+
+    fn size(&self) -> u64 {
+        self.size
+    }
+
+    fn read(&mut self, block: u64, buffer: &mut [u8]) -> Result<usize> {
+        self.port.ata_dma(block, buffer.len() / 512, buffer.as_ptr() as usize, false)
+    }
+
+    fn write(&mut self, block: u64, buffer: &[u8]) -> Result<usize> {
+        self.port.ata_dma(block, buffer.len() / 512, buffer.as_ptr() as usize, true)
+    }
+}
diff --git a/drivers/ahcid/src/main.rs b/drivers/ahcid/src/main.rs
new file mode 100644
index 0000000..5f7b1a1
--- /dev/null
+++ b/drivers/ahcid/src/main.rs
@@ -0,0 +1,35 @@
+#![feature(asm)]
+
+#[macro_use]
+extern crate bitflags;
+extern crate io;
+extern crate syscall;
+
+use std::{env, thread, usize};
+
+use syscall::{iopl, physmap, physunmap, MAP_WRITE};
+
+pub mod ahci;
+
+fn main() {
+    let mut args = env::args().skip(1);
+
+    let bar_str = args.next().expect("ahcid: no address provided");
+    let bar = usize::from_str_radix(&bar_str, 16).expect("ahcid: failed to parse address");
+
+    let irq_str = args.next().expect("ahcid: no irq provided");
+    let irq = irq_str.parse::<u8>().expect("ahcid: failed to parse irq");
+
+    thread::spawn(move || {
+        unsafe {
+            iopl(3).expect("ahcid: failed to get I/O permission");
+            asm!("cli" :::: "intel", "volatile");
+        }
+
+        let address = unsafe { physmap(bar, 4096, MAP_WRITE).expect("ahcid: failed to map address") };
+        {
+            ahci::Ahci::disks(address, irq);
+        }
+        unsafe { physunmap(address).expect("ahcid: failed to unmap address") };
+    });
+}
diff --git a/drivers/pcid/src/main.rs b/drivers/pcid/src/main.rs
index 9eb0889..a34ff17 100644
--- a/drivers/pcid/src/main.rs
+++ b/drivers/pcid/src/main.rs
@@ -120,17 +120,25 @@ fn main() {
                                             }
                                         };
                                         let arg = match arg.as_str() {
-                                            "$0" => bar_arg(0),
-                                            "$1" => bar_arg(1),
-                                            "$2" => bar_arg(2),
-                                            "$3" => bar_arg(3),
-                                            "$4" => bar_arg(4),
-                                            "$5" => bar_arg(5),
+                                            "$BAR0" => bar_arg(0),
+                                            "$BAR1" => bar_arg(1),
+                                            "$BAR2" => bar_arg(2),
+                                            "$BAR3" => bar_arg(3),
+                                            "$BAR4" => bar_arg(4),
+                                            "$BAR5" => bar_arg(5),
+                                            "$IRQ" => format!("{}", header.interrupt_line),
                                             _ => arg.clone()
                                         };
                                         command.arg(&arg);
                                     }
-                                    println!("{:?}", command);
+
+                                    match command.spawn() {
+                                        Ok(mut child) => match child.wait() {
+                                            Ok(_status) => (), //println!("pcid: waited for {}: {:?}", line, status.code()),
+                                            Err(err) => println!("pcid: failed to wait for {:?}: {}", command, err)
+                                        },
+                                        Err(err) => println!("pcid: failed to execute {:?}: {}", command, err)
+                                    }
                                 }
                             }
 
diff --git a/initfs/etc/pcid.toml b/initfs/etc/pcid.toml
index ec6c838..996b9a8 100644
--- a/initfs/etc/pcid.toml
+++ b/initfs/etc/pcid.toml
@@ -2,4 +2,4 @@
 name = "AHCI storage"
 class = 1
 subclass = 6
-command = ["ahcid", "$5"]
+command = ["initfs:bin/ahcid", "$BAR5", "$IRQ"]
diff --git a/kernel/scheme/debug.rs b/kernel/scheme/debug.rs
index 52b88e5..eed44ed 100644
--- a/kernel/scheme/debug.rs
+++ b/kernel/scheme/debug.rs
@@ -72,7 +72,7 @@ impl Scheme for DebugScheme {
         Ok(buffer.len())
     }
 
-    fn fevent(&self, _file: usize, flags: usize) -> Result<usize> {
+    fn fevent(&self, _file: usize, _flags: usize) -> Result<usize> {
         Ok(0)
     }
 
diff --git a/kernel/syscall/mod.rs b/kernel/syscall/mod.rs
index 1bb5a56..2815091 100644
--- a/kernel/syscall/mod.rs
+++ b/kernel/syscall/mod.rs
@@ -47,8 +47,11 @@ pub extern fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize
             SYS_GETCWD => getcwd(validate_slice_mut(b as *mut u8, c)?),
             SYS_FEVENT => fevent(b, c),
             SYS_FPATH => fpath(b, validate_slice_mut(c as *mut u8, d)?),
+            SYS_PHYSALLOC => physalloc(b),
+            SYS_PHYSFREE => physfree(b, c),
             SYS_PHYSMAP => physmap(b, c, d),
             SYS_PHYSUNMAP => physunmap(b),
+            SYS_VIRTTOPHYS => virttophys(b),
             _ => {
                 println!("Unknown syscall {}", a);
                 Err(Error::new(ENOSYS))
diff --git a/kernel/syscall/process.rs b/kernel/syscall/process.rs
index 5150b95..d953e42 100644
--- a/kernel/syscall/process.rs
+++ b/kernel/syscall/process.rs
@@ -8,7 +8,7 @@ use spin::Mutex;
 
 use arch;
 use arch::externs::memcpy;
-use arch::memory::allocate_frame;
+use arch::memory::{allocate_frame, allocate_frames, deallocate_frames, Frame};
 use arch::paging::{ActivePageTable, InactivePageTable, Page, PhysicalAddress, VirtualAddress, entry};
 use arch::paging::temporary_page::TemporaryPage;
 use arch::start::usermode;
@@ -535,6 +535,16 @@ pub fn iopl(_level: usize) -> Result<usize> {
     Ok(0)
 }
 
+pub fn physalloc(size: usize) -> Result<usize> {
+    allocate_frames((size + 4095)/4096).ok_or(Error::new(ENOMEM)).map(|frame| frame.start_address().get())
+}
+
+pub fn physfree(physical_address: usize, size: usize) -> Result<usize> {
+    deallocate_frames(Frame::containing_address(PhysicalAddress::new(physical_address)), (size + 4095)/4096);
+    //TODO: Check that no double free occured
+    Ok(0)
+}
+
 //TODO: verify exlusive access to physical memory
 pub fn physmap(physical_address: usize, size: usize, flags: usize) -> Result<usize> {
     if size == 0 {
@@ -617,6 +627,14 @@ pub fn sched_yield() -> Result<usize> {
     Ok(0)
 }
 
+pub fn virttophys(virtual_address: usize) -> Result<usize> {
+    let active_table = unsafe { ActivePageTable::new() };
+    match active_table.translate(VirtualAddress::new(virtual_address)) {
+        Some(physical_address) => Ok(physical_address.get()),
+        None => Err(Error::new(EFAULT))
+    }
+}
+
 pub fn waitpid(pid: usize, status_ptr: usize, flags: usize) -> Result<usize> {
     loop {
         {
diff --git a/syscall/src/lib.rs b/syscall/src/lib.rs
index 2f4ea89..15ac101 100644
--- a/syscall/src/lib.rs
+++ b/syscall/src/lib.rs
@@ -114,6 +114,14 @@ pub fn open(path: &str, flags: usize) -> Result<usize> {
     unsafe { syscall3(SYS_OPEN, path.as_ptr() as usize, path.len(), flags) }
 }
 
+pub unsafe fn physalloc(size: usize) -> Result<usize> {
+    syscall1(SYS_PHYSALLOC, size)
+}
+
+pub unsafe fn physfree(physical_address: usize, size: usize) -> Result<usize> {
+    syscall2(SYS_PHYSFREE, physical_address, size)
+}
+
 pub unsafe fn physmap(physical_address: usize, size: usize, flags: usize) -> Result<usize> {
     syscall3(SYS_PHYSMAP, physical_address, size, flags)
 }
@@ -138,6 +146,10 @@ pub fn unlink(path: &str) -> Result<usize> {
     unsafe { syscall2(SYS_UNLINK, path.as_ptr() as usize, path.len()) }
 }
 
+pub unsafe fn virttophys(virtual_address: usize) -> Result<usize> {
+    syscall1(SYS_VIRTTOPHYS, virtual_address)
+}
+
 pub fn waitpid(pid: usize, status: &mut usize, options: usize) -> Result<usize> {
     unsafe { syscall3(SYS_WAITPID, pid, status as *mut usize as usize, options) }
 }
diff --git a/syscall/src/number.rs b/syscall/src/number.rs
index c0f341c..b0d41c0 100644
--- a/syscall/src/number.rs
+++ b/syscall/src/number.rs
@@ -20,8 +20,11 @@ pub const SYS_LSEEK: usize = 19;
 pub const SYS_MKDIR: usize = 39;
 pub const SYS_NANOSLEEP: usize = 162;
 pub const SYS_OPEN: usize = 5;
-pub const SYS_PHYSMAP: usize = 945;
-pub const SYS_PHYSUNMAP: usize = 946;
+pub const SYS_PHYSALLOC: usize = 945;
+pub const SYS_PHYSFREE: usize = 946;
+pub const SYS_PHYSMAP: usize = 947;
+pub const SYS_PHYSUNMAP: usize = 948;
+pub const SYS_VIRTTOPHYS: usize = 949;
 pub const SYS_PIPE2: usize = 331;
 pub const SYS_READ: usize = 3;
 pub const SYS_RMDIR: usize = 84;