diff --git a/kernel/Makefile b/kernel/Makefile
index 76431c5..51d909e 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -37,6 +37,7 @@ SRCS	= kernel.asm \
 			fs/xv6fs.inc \
 			vfs.inc \
 			proc.inc \
+			bio.inc \
 			$(ASMINCS)
 
 .PHONY: all
diff --git a/kernel/bio.inc b/kernel/bio.inc
new file mode 100644
index 0000000..d9c56e2
--- /dev/null
+++ b/kernel/bio.inc
@@ -0,0 +1,33 @@
+	;; File: bio.inc
+	;; Buffer cache
+
+	;; Struc: Buffer
+struc Buffer {
+	.dev      dd ?
+	.block    dd ?
+	.ulock    dd ?
+	.refcount dd ?
+	.data db 512 dup(?)
+}
+DEFN Buffer
+
+	;; Function: bio_init
+bio_init:
+	mov ecx, sizeof.Buffer * 30
+	xor ax, ax
+	mov edi, aBuffers
+	rep stosb
+	ret
+
+bio_get:
+	mov eax, uBIOLock
+	call lock_acquire
+
+	mov eax, uBIOLock
+	call lock_release
+	ret
+
+bio_brelse:
+	ret
+
+uBIOLock dd 0
diff --git a/kernel/dev/at/ata.inc b/kernel/dev/at/ata.inc
index 7bf4505..266fc47 100644
--- a/kernel/dev/at/ata.inc
+++ b/kernel/dev/at/ata.inc
@@ -1,7 +1,8 @@
 	;; File: ata.inc
 	;;
-	;; <ATA PIO Mode at https://wiki.osdev.org/ATA_PIO_Mode>
-	;; <IDE spec at https://www.cpcwiki.eu/imgs/a/a2/IDE_SPEC.PDF>
+	;; Usefull links:
+	;; - <ATA PIO Mode at https://wiki.osdev.org/ATA_PIO_Mode>
+	;; - <IDE spec at https://www.cpcwiki.eu/imgs/a/a2/IDE_SPEC.PDF>
 
 ATA_PRIMARY_IO        = 0x1F0
 ATA_PRIMARY_IO_CTRL   = 0x3F6
@@ -76,10 +77,21 @@ ATA_CMD_IDENTIFY   = 0xA0
 ata_wait:
 	mov dx, ax
 	add dx, ATA_STATUS
+	xor ecx, ecx
 @@:
+	inc ecx
+	cmp ecx, 5000
+	jg @f
 	in al, dx
 	and al, ATA_STATUS_BSY
 	jnz @b
+@@:
+	ret
+
+ata_select:
+	ret
+
+ata_cmd:
 	ret
 
 	;; Function: ata_probe
@@ -102,7 +114,9 @@ ata_probe:
 	out dx, al
 
 	mov ax, bx
+	push ecx
 	call ata_wait
+	pop ecx
 
 	mov dx, bx
 	add dx, ATA_COMMAND
@@ -110,16 +124,20 @@ ata_probe:
 	out dx, al
 
 	mov ax, bx
+	push ecx
 	call ata_wait
+	pop ecx
 
 	mov dx, bx
 	add dx, ATA_STATUS
 	in al, dx
 	and al, ATA_STATUS_ERR or ATA_STATUS_DRQ
-	jnz @f
+	jnz .skip
 
 	mov ax, bx
+	push ecx
 	call ata_wait
+	pop ecx
 
 	mov dx, bx
 	add dx, ATA_COMMAND
@@ -127,20 +145,39 @@ ata_probe:
 	out dx, al
 
 	mov ax, bx
+	push ecx
 	call ata_wait
+	pop ecx
 
 	mov dx, bx
 	add dx, ATA_STATUS
 	in al, dx
 	and al, ATA_STATUS_ERR or ATA_STATUS_DRQ
-	jnz @f
+	jnz .skip
 
 	push ecx
+	cmp ecx, ATA_CHAN1_IO
+	jne @f
+	add ecx, 2
+	jmp .drive_found
+@@:
+	cmp ecx, ATA_CHAN2_IO
+	jne @f
+	add ecx, 4
+	jmp .drive_found
+@@:
+	cmp ecx, ATA_CHAN3_IO
+	jne @f
+	add ecx, 8
+	jmp .drive_found
+@@:
+.drive_found:
+
 	push ecx
 	mov esi, szMsgAtaFound
 	call klog
 	pop ecx
-@@:
+.skip:
 	inc cl
 	cmp cl, 2
 	jb .loop
@@ -172,9 +209,9 @@ ata_device:
 
 aAtaChans:
 	dw ATA_CHAN0_IO
-;	dw ATA_CHAN1_IO
-;	dw ATA_CHAN2_IO
-;	dw ATA_CHAN3_IO
+	dw ATA_CHAN1_IO
+	dw ATA_CHAN2_IO
+	dw ATA_CHAN3_IO
 .end:
 
 szMsgAtaFound db "ATA: hd%u found", 0
diff --git a/kernel/kernel.asm b/kernel/kernel.asm
index 984f141..562d74d 100644
--- a/kernel/kernel.asm
+++ b/kernel/kernel.asm
@@ -79,6 +79,8 @@ kmain:
 
 	call pit_init
 
+	call bio_init
+
 	call proc_init
 
 	call dev_init
@@ -116,6 +118,7 @@ kmain:
 	include 'fs/stpdfs.inc'
 	include 'fs/xv6fs.inc'
 	include 'proc.inc'
+	include 'bio.inc'
 
 
 szMsgKernelAlive db "Kernel (", VERSION_FULL , ") is alive", 0
@@ -126,7 +129,10 @@ boot_structure BootInfo
 
 kTSS TSS
 
+	align 4096
 aProcs rb 64*sizeof.Process
+	align 4096
+aBuffers rb 30*sizeof.Buffer
 
 	align 4096
 stack_bottom: