GUIDE

This guide is divided into two sections:
	1. New users guide
	2. Developers guide
Section 1:
	1.1 What is bootOS?
	  bootOS is a monolithic operating system that fits in
	  one boot sector. It's able to load, execute, and save
	  programs. Also keeps a filesystem. It can work with
	  any type of data storage.

	  It relocates itself at 0000:7a00 and requires further
	  768 bytes of memory starting at 0000:7700.

	  This operating system runs programs as boot sectors
	  at 0000:7c00

	1.2 What are the benefits of this bootOS?
	  * Better line handling
	  * More filespace (uses LBA)
	  * More interrupts
          * Geometry independent
	  * Software builder
	  * Unlimited files

	1.3 How can I run it?
	  First of all, you need the packages "nasm", "qemu-kvm", "make" and "python3".
	  bootOS is designed to be build on Linux (Debian) and wasn't tested somewhere else.
	  To build a blank system without any software, you can run "make os.img". This can
	  be done on Windows too.
	  To build a system including all software, you can run "make software".
	  If you want to exclude software, just add "E=software_src/something" at the beginning.
	  If you want to build the installer, you can run "make installer".
	  When you have booted the installer, you
	  have to enter your drive's id. You can find the id under https://en.wikipedia.org/wiki/INT_13H#List_of_INT_13h_services.
	  Note: Your boot drive has the id 80 or 00 if you are using a floppy disk. The installation should output the error code 0x00.
		  Error code 0x01:
		        Drive not readable. Is your usb stick plugged in?
		  Error code 0x02:
		        Drive is not writeable. Is it the CD ROM or something other?
		  Error code 0x03:
		        Source and target are the same drive.
		  Error code 0x04:
		        Already installed. Eject the CD/USB
	1.4 How can contribute even though I cannot program?
	  You can try it and try to find bugs. ;)

Section 2:
	2.1 Setup a small program
	  The base program is very simple:
	    org 0x7c00
	    bits 16
	    exit
	2.2 A reference for all interrupts provided by bootOS
	    int 0x20   Exit to operating system.
	    int 0x21   Input key and show in screen.
                Entry: none
                Output: AL = ASCII key pressed.
                Affects: AH/BX/BP.
	    int 0x22   Output character to screen.
                Entry: AL = Character.
                Output: none.
                Affects: AH/BX/BP.
	    int 0x23   Load file.
                Entry: DS:BX = Filename terminated with zero.
                       ES:DI = Point to source data (512 bytes)
                Output: Carry flag = 0 = Found, 1 = Not found.
                Affects: All registers (including ES).
	    int 0x24   Save file.
                Entry: DS:BX = Filename terminated with zero.
                       ES:DI = Point to data target (512 bytes)
                Output: Carry flag = 0 = Successful. 1 = Error.
                Affects: All registers (including ES).
	    int 0x25   Delete file.
                Entry: DS:BX = Filename terminated with zero.
                Affects: All registers (including ES).
	    int 0x26   Input line and save it to 0x7780.
                Entry: AL = promt character
                Affects: I don't know
	2.3 The magic offsets
	  bootOS provides two important offsets on build:
	    * DB S
	    * DW HD
	  DB S is the offset where you can change the section. It's one byte.
	  DW HD is the offset where you can change the drive and head. It's a word 0xhhdd.
	  Note: it's safer and more beatiful to use the symbols in sysmap.inc!
	2.4 The breakpoint
	  If you want your code to run every loop before the "int int_input_line", you can replace the
	  interrupt 0x27 with your code. This is used in the clock as you can see.
	2.5 sysmap.inc
	  sysmap.inc can be generated with "make symbols" and can be used to link your program
	  to the running system. You just have to add '%include "../sysmap.inc"' to use the labels.
	  This can be very useful to not waste space for code you already have in memory.
	  Labels start with "bootOS.". (e.g. "bootOS.restart")
          This file provides the exit instruction.
	2.6 32-bit access
	  Note: this article is about init32.
	  A 80386 or higher microprocessor allows you to access memory with 32-bit registers
	  as long as you use the Address Size Override Prefix. Nasm does this usually when you
	  don't define the bits (e.g. not "bits 16"). 

will be expanded...