diff --git a/boot/kernel.asm b/boot/kernel.asm
index 8d05b5a..1b37760 100644
--- a/boot/kernel.asm
+++ b/boot/kernel.asm
@@ -1,32 +1,18 @@
 		cpu 8086
-		org 0x500
+		org 0x7C00
 
 %include	"inc/bpb.asm"
-%include	"inc/dpt.asm"
-
-; drive table entry
-struc drive
-.biosnum:	resb 1
-.flag:		resb 1
-.spc:		resw 1
-.cylinders:	resw 1
-.dpt:		resb dpt_size
-.type:		resb 1 ; 12 or 16, depending on FAT type
-.fat_offset:	resd 1 ; offset of fat table
-.fat_num:	resw 1 ; number of fat tables
-.fat_size:	resw 1 ; sectors per fat table
-
-.dir_offset:	resd 1 ; offset of root directory
-.dir_size:	resw 1 ; size of root directory in sectors
-
-.clus_offset:	resd 1 ; offset of clusters
-.clus_num:	resw 1 ; number of clusters
-.clus_size:	resw 1 ; sectors per cluster
-endstruc
+%include	"inc/mbr.asm"
 
 		; kernel stack size in words
 %define		stacksize 512
 
+		jmp init
+
+		times ( 0x0B - ($-$$) ) db " "
+
+		times bpb_size db 0
+
 init:		cli
 		xor ax, ax
 		mov ds, ax
@@ -34,243 +20,11 @@ init:		cli
 		mov ss, ax
 		mov sp, ( stack+stacksize )
 
-		; relocate
-		mov si, 0x7C00
-		mov di, $$
-		mov cx, (_end-$$)
-		rep movsb
-
-		jmp 0:main
-
-main:		; zero out first 64kb except our code
-		; bss and boot sector area gets cleared by this
-		mov cx, di
-		neg cx
-		xor ax, ax
-		rep stosb
-
-		; install interrupt vectors
-		mov si, vects
-		mov di, (0x20*4)
-		mov cx, 0x0A
-intlp:		movsw
-		mov ax, cs
-		stosw
-		loop intlp
-
-		mov dx, banner
-		call puts
-
-		call drives_init
-
-		mov dl, 0
-		call drive_select
-		xor ax, ax
-		xor dx, dx
-		call drive_seek
-		call drive_read
-		mov ax, [diskbuf+0x1FE]
 		int 3
 
-loop:		int 0x28
-		jmp loop
-
-section .data
-
-banner:	db "rdos loaded", 0xA, 0xD, '$'
-
-section .text
-
-	; Alias for Int 21h,AH=0h
-int20h:	xor ah, ah
-	jmp far [cs:0x21*4]
-
-int21h:	; inside of kernel, direction always goes up
-	; the iret will restore it to the user value later
-	cld
-	; set sfptr from ah
-	push bx
-	xor bx, bx
-	mov bl, ah
-	add bl, bl
-	add bx, sftab
-	mov bx, [cs:bx]
-	mov [cs:sfptr], bx
-	pop bx
-	; do the actual subfunction call
-	call [cs:sfptr]
-	; inherit the lower 8 flag bits to userspace
-iretfl:	push ax
-	push bp
-	mov bp, sp
-	lahf
-	mov [bp+8], ah
-	pop bp
-	pop ax
-	; iret frame: IP CS FLAGS
-iret:	iret
-retf:	retf
-
-section .data
-
-	; Subfunction ptr
-	; this is used as extra register in int21h
-sfptr:	dw 0
-
-	; Subfunction table
-sftab:	dw sferr, getc, putc, sferr
-	dw sferr, sferr, conout, conin
-	dw sferr, puts, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	; 10
-	dw sferr, sferr, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	; 20
-	dw sferr, sferr, sferr, sferr
-	dw sferr, setint, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	; 30
-	dw sferr, sferr, sferr, sferr
-	dw sferr, getint, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-	dw sferr, sferr, sferr, sferr
-
-section .text
-
-	; OUT	al	character read
-getc:	xor ax, ax
-	int 0x16
-	push ax
-	jmp putc.2
-
-	; IN	dl	character to write
-putc:	push ax
-	mov al, dl
-.2:	int 0x29
-	pop ax
-	ret
-
-	; console output
-	; IN	dl	character
-conout:	cmp dl, 0xFF
-	je conine
-	push ax
-	mov al, dl
-	int 0x29
-	pop ax
-	ret
-
-	; console input with echo
-	; OUT	al	character
-	;	zf	clear when character available
-conine:	mov ah, 1
-	int 0x16
-	jnz .has
-	xor al, al
-	ret
-.has:	xor ax, ax
-	int 0x16
-	test al, al
-	jz conine
-	int 0x29
-	test ax, ax
-	ret
-
-	; console input without echo
-	; OUT	al	character
-	;	zf	clear when character available
-conin:	mov ah, 1
-	int 0x16
-	jnz .has
-	xor al, al
-	ret
-.has:	xor ax, ax
-	int 0x16
-	test al, al
-	jz conin
-	test ax, ax
-	ret
-
-	; DOS 1+ 9h - WRITE STRING TO STANDARD OUTPUT
-	; IN	ds:dx	'$'-terminated string
-puts:	push si
-	mov si, dx
-.loop:	lodsb
-	cmp al, '$'
-	je .end
-	int 0x29
-	jmp .loop
-.end:	pop si
-	ret
-
-	; DOS 1+ 25h - SET INTERRUPT VECTOR
-	; IN	al	interrupt number
-	;	ds:dx	entry point
-setint:	push bx
-	xor bx, bx
-	; BX=AL*4
-	mov bl, al
-	add bl, bl
-	add bl, bl
-	; save DS:DX into vector
-	mov [cs:bx], dx
-	mov [cs:bx+2], ds
-	pop bx
-	ret
-
-	; DOS 2+ 35h - GET INTERRUPT VECTOR
-	; IN	al	interrupt number
-	; OUT	es:bx	current interrupt handler
-getint:	xor bx, bx
-	; BX=AL*4
-	mov bl, al
-	add bl, bl
-	add bl, bl
-	; load vector into ES:BX
-	les bx, [cs:bx]
-	ret
-
-	; Fallback for non-existant subfunctions
-	; The carry flag is inherited to user
-sferr:	stc
-	ret
-
-	; DOS IDLE INTERRUPT
-	; Usually hooked by TSRs
-idle:	sti
-	; sti takes one instruction to take effect
-	nop
-	; Wait until next interrupt
-	hlt
-	iret
-
-	; FAST CONSOLE OUTPUT
-	; IN	al	character to print
-fputc:	push ax
-	push bx
-	mov ah, 0x0E
-	xor bx, bx
-	int 0x10
-	pop bx
-	pop ax
-	iret
-
-	%include "kernel/drive.asm"
-	%include "kernel/fat.asm"
-
-zero:	dw 0
-
-section .data
-
-vects:	dw int20h, int21h, retf, retf
-	dw retf, retf, retf, int20h
-	dw idle, fputc
-
-_end:	dw 0x55AA, 0x55AA
+hlt:		hlt
+		jmp hlt
 
 section .bss
-		; stack to be used during init and disk i/o
-stack:		resw stacksize
+
+stack:		resb stacksize
diff --git a/kernel/main.asm b/kernel/main.asm
new file mode 100644
index 0000000..5ab8421
--- /dev/null
+++ b/kernel/main.asm
@@ -0,0 +1,36 @@
+		cpu 8086
+		org 0x7C00
+
+		jmp init
+
+%include	"kernel/fd.asm"
+%include	"kernel/con.asm"
+
+entry_int21:	iret
+
+init:		; install int 21h handler
+		mov ax, cs
+		mov ds, ax
+		mov es, ax
+		mov word [4*0x21], entry_int21
+		mov word [4*0x21+2], cs
+
+		mov word [fd_table], con_ftab
+
+		; print banner
+		mov dx, .banner
+		mov cx, 13
+		mov bx, 0
+		call con_write
+
+		; execute shell
+		mov ax, 0x4B00
+		mov dx, .shellfn
+		int 0x21
+
+.hlt:		hlt
+		jmp .hlt
+
+.banner:	db "rdos kernel", 0x0A, 0x0D
+
+.shellfn:	db "SHELL.COM", 0