The Beans' Operating System

Downloads
Source Code 
Screen Shots
 

The Forum
Beans'OS forum
About author

Welcome to Beans'OS

  The Beans' Operating System is an Open Source project aimed at building a "simple and complete" operating system on x86 architecture, for fun of the guys who are interested in low level programming. the purpose of this project is researching and practising, only the "basic but correct" code is to be expected. Therefore, the kernel would never copy or port any other source code of famous open source OS. but the drivers may limitedly refer to some code from experimental OS which has already given up its copyright.                            

  The source code of   beans' is written by C and Assemble languages.

  Beans'OS is developed under the GNU General Public License. There is a copy of GPL in the source code package.

  NOTE: The applications that use kernel services or libs using system calls are not a part of this project and the copy right of them belongs to their author.

  Kernel of beans'OS ,some user spaces lib and applications are built and tested in the linux environment. and to be written into a floppy image, the floppy image is bootable, can be tested in a real PC with x86 CPU using a real floppy. as well as the virtual machines using the image.
 

Current Achievement

Kernel part

*Memory Management:
   Use First Matching method manage the 4k size pages.
   Use Slab structures manage small size memory allocation.
   Page allocations delay until a page fault happen.

*Process Management:
   Use Feed back priority arithmetic to organize the multi-processes.
   Every process has its own 2G virtual address of user space and 2G virtual address of kernel space.
   After a process exitting, the resource of the process will be called back. At system level, the memory leak will be prevented.
   Sleep and wakeup are enabled.
   Kernel can load and execute the ELF format executable file linked in use of the default ld script under linux(four section are needed at least: data, rodata, bss, text).

*Access protection:
   Support all the functions offered by protection mode of x86 to protect memory operation, IO operation and soft interrupt operation.
   At kernel mode, all resource can be access but at user mode, only the resource belong to the current process can be accessed.

*File system
   A read-only dos fat12 has be driven, it is compatible with the file system supported by windows and linux, so you can mount beans' image to those system and access files.

*Drivers
   Mouse, keyboard, character console, timer, floppy and the interrupts controller.

*System call
   Until now, support a little system call:
   print, exit, pause, brk, get_command_param, get_heap_size

*Kernel libs
   Functions for memory management and string operation, also there are some math functions.

User part

*Libs
   Some common functions.
   Port glibc's memory management part.

*Demos
  The basic demos show how to program for beans', they are:
  1, Huge number adding program.
  2, A program lists all the result of multiplication from 1 to 9.
  3, Josephus question, which acts how to use a circle list. it is the test demo for malloc and free.
 

Parts of POSIX will be supported More and more.

Develop Tools

  Redhat linux(Fedora core 1 with kernel 2.4.22-1.2115.nptl)
  Gcc 3.3.2
  Nasm 0.98.38
  GNU ld 2.14.90.0.6

Test Tools

  Computer 1: compatible PC
    p4 1.8G
    512M RAM
    MSI main-board
    Nec ISA floppy driver
    Any ps2 mouse and keyboard

  Computer 2: DELL OPTIPLEX GX620
    p4 3.0
    1G RAM

  VMware 4.0.5 linux-version

  VMware 5.0.0 windows-version

  Bochs x86 Emulator 2.3 linux-version

  Bochs x86 Emulator 2.3 windows-version  

How to compile the kernel of beans'OS and make a bootable image?

Under linux, this is so easy.

  1, Change dir to src/beans

  2, Use "make" command, this will build three new files: kernel, bootsect, setup
besides the kernel, the bootsect and setup are made to be the "boot program and the kernel loader"

  3, According to the cue of the makefile's output, use "./makeimg xx.img" this will make a new bootable floppy image named "xx.img".
  makeimg is a tool, its source code is in dir src/tool.

  Some one has a successful experience to compiler this kernel under windows but I never do that. Maybe you should find the gcc and nasm for windows version.

How to write applications for beans'OS?

  1, Write your application normally as write it for linux.

  2, Include "applib.h" as a header file.

  3, Add a macro "APP_ENTRY" before the first function of your program. (normally, this should be after the statement of global variables).

  4, Use gcc as the compiler, add the following option:
     -ffreestanding -nostdlib -fno-builtin -nostdinc -fno-exceptions -Wall

  5, Use ld as the linker, add the following option:
     -Ttext 0x80000000 -e app_entry
     All beans' applications begin from virtual addr 2G

  6, Set the executable file's extend name as ".ex"
     For example: you should give the name "hello.ex" for your first "hello world"    program.

  7, Mount the bootable kernel image to linux. and copy your program to the mount dir
     For example: you make a kernel and use "./makeimg bootimg.img" to get a bootable floppy image named "bootimg.img". Also, you make an application named "hello.ex",you should input as following:
     mount bootimg.img /mnt -o loop
     cp hello.ex /mnt/hello.ex
     umount bootimg.img

     Make sure the umount operation success, if umount fails, you may still open or use the files under /mnt dir

  8, Now, you have got a bootable image include the kernel and the filesystem.
If you want to run it in a real PC, you should insert a floppy disk into your old floppy driver and use the command:

 "cat bootimg.img > /dev/fd0"

  this command will dupe the floppy image to a real floppy disk. then, set the computer boot sequence in bios, move the "floppy boot" first, reboot.

    If you has a virtual machine, you can set the bootable image as the virtual machine's floppy disk, and reboot the virtual machine

  9, After startup of beans'OS , like unix shell, you can use some command listed at screen. Use "cd dir" to the dir which contains your hello.ex and type "hello.ex" . that's all.

  Anyway, the demos in src/app/ is the best example, read the Makefile and Rules.make of them. they are all very simple.

How to join this project and write something for the kernel?

  1, Write me a mail to this address beansos@gmail.com.
  2, Write and test your codes, if you think these codes work well, you can submit it at the forum"code submit" place( Code Submit ) using ".tar.gz" format. also, a "readme" file is necessary. if they are really good enough, your codes will be added to kernel when next version comes out.
  3, Never forget to upgrade your code.

Page maintained by Shaojie Zhou