├── Makefile
├── README.rst
├── a.img.gz
├── bochsrc
└── boot.asm


/Makefile:
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1 | run :
2 | 	gzip -cd a.img.gz > a.img
3 | 	nasm boot.asm -o boot.bin
4 | 	dd if=boot.bin of=a.img bs=512 count=1 conv=notrunc
5 | 	bochs
6 | 
7 | clean :
8 | 	rm -f a.img boot.bin
9 | 


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/README.rst:
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 1 | Operating System From Scratch
 2 | -----------------------------
 3 | 
 4 | Step 01: A smallest "OS"
 5 | ````````````````````````
 6 | 
 7 | Let's begin with a simplest boot sector. You'll see how easy it is to get started!
 8 | 
 9 | Here we go:
10 | 
11 | + Install nasm_ the assembly compiler and bochs_ the emulator
12 | 
13 | + Clone me (we're in GitHub, aren't we)::
14 | 
15 |       $ git clone https://github.com/yyu/osfs01.git
16 | 
17 | + Run your smallest "OS" right now::
18 | 
19 |       $ cd osfs01
20 |       $ make
21 | 
22 |   Guess what? It's running!
23 | 
24 |   .. image:: http://osfromscratch.org/snapshots/original/%E5%9B%BE01.01%20%E6%9C%80%E5%B0%8F%E7%9A%84%E2%80%9C%E6%93%8D%E4%BD%9C%E7%B3%BB%E7%BB%9F%E2%80%9D.png
25 | 
26 |   The screen is a little messy but you can see the red "Hello, OS world!", which means our boot sector works!
27 | 
28 | `‹prev`_   `next›`_
29 | 
30 | .. _nasm: http://nasm.us/
31 | .. _bochs: http://bochs.sourceforge.net/
32 | .. _`‹prev`: https://github.com/yyu/osfs00
33 | .. _`next›`: https://github.com/yyu/osfs02
34 | 


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/a.img.gz:
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https://raw.githubusercontent.com/yyu/osfs01/8be03bd1bd933c831bf65d23cea13a55515baeec/a.img.gz


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/bochsrc:
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 1 | ###############################################################
 2 | # Configuration file for Bochs
 3 | ###############################################################
 4 | 
 5 | # how much memory the emulated machine will have
 6 | megs: 32
 7 | 
 8 | # filename of ROM images
 9 | romimage: file=/usr/share/bochs/BIOS-bochs-latest
10 | vgaromimage: file=/usr/share/vgabios/vgabios.bin
11 | 
12 | # what disk images will be used
13 | floppya: 1_44=a.img, status=inserted
14 | 
15 | # choose the boot disk.
16 | boot: floppy
17 | 
18 | # where do we send log messages?
19 | # log: bochsout.txt
20 | 
21 | # disable the mouse
22 | mouse: enabled=0
23 | 
24 | # enable key mapping, using US layout as default.
25 | keyboard_mapping: enabled=1, map=/usr/share/bochs/keymaps/x11-pc-us.map
26 | 


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/boot.asm:
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 1 | 	org	07c00h			; where the code will be running
 2 | 	mov	ax, cs
 3 | 	mov	ds, ax
 4 | 	mov	es, ax
 5 | 	call	DispStr			; let's display a string
 6 | 	jmp	$			; and loop forever
 7 | DispStr:
 8 | 	mov	ax, BootMessage
 9 | 	mov	bp, ax			; ES:BP = string address
10 | 	mov	cx, 16			; CX = string length
11 | 	mov	ax, 01301h		; AH = 13,  AL = 01h
12 | 	mov	bx, 000ch		; RED/BLACK
13 | 	mov	dl, 0
14 | 	int	10h
15 | 	ret
16 | BootMessage:		db	"Hello, OS world!"
17 | times 	510-($-$$)	db	0	; fill zeros to make it exactly 512 bytes
18 | dw 	0xaa55				; boot record signature
19 | 


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