Welcome to FoolOS
=================

Disclaimer
----------

THIS IS A WORK IN PROGRESS.

This is a simple and useless "operating system", with very basic 
features, sorry. It is the fruit of my fundamental explorations of 
the x86 architectures,  32-bit protected mode, interrupt handling, 
memory management, scheduling, the floppy disk controller, networking 
as well as VESA and a couple of other things.

![Screenshot of FoolOS](/screenshots/foolos.png?raw=true "FoolOs Kernel")

Copyright M.Idziorek 2014 <m.i@gmx.at> unless stated otherwise!

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Usage
-----

Attach the FoolOS.img (found in the ./release directory) floppy image in your 
favourite emulator and boot or create a bootable USB stick by copying the raw 
data in the following way:

$ cat ./release/FloppyOS.img > /dev/sdX

This image is not updated on every commit, so it might be out of date.
You can build it yourself by running "make" in the projects 
directory. You might need some dependencies (as newlib) however. 


Supported Platforms
-------------------

FoolOS is tested/developed on the following emulators/machines

* bochs 2.6.6 (compiled with: ./configure --enable-clgd54xx --enable-a20-pin --enable-debugger --enable-disasm --enable-e1000 --with-x --with-x11 --enable-smp)
* qemu 1.1.2
* virtual box 4.1.18
* Acer Aspire 1810TZ (Notebook)
* Q6600 on Asus p5n32-e sli plus (Desktop PC)

Features
--------

Please note that all features are only very rudimentary and buggy.
Some might be disabled temporarily due to conflicts or regressions.

* Bootloader (2 stages)
* PIT support / Timing
* PIC support & Interrupt handling framework
* PCI bus scanning
* Physical memory management
* Virtual memory management
* Multitasking
* Symmetric Multiprocessing
* ACPI / MP
* Floppy disk driver
* PS2 Mouse driver
* Keyboard driver (redesign!)
* VESA 
* Spinlocks
* Simple Shell
* Simple Ext2 driver (read-only)

Todos
-----

* set up os-specific toolchain!
* set dependancies in the makefile properly!

* User space
* ELF binaries
* reenable virtual memory!
* reenable SMP and MULTITASKING!
* implement more syscalls: fork, execv

* E1000 driver
* Networking stack 
* copy files over network! read/write

* window manager

* 64-bit
* ARM
* JVM
* USB driver
* Higher half kernel
* Web-server
* Port coreutils, gcc?

Issues
------

* Turning on some gcc optimizations breaks the kernel
* Assumed support for VESA mode 0x114 with linear addressing.
* Control of stack heap growth?
* Protect ringbuffer in syscall: disable interrupts on local cpu before spinlocking


Organization
------------

* asm/	- NASM assembler files
* bochs/ -Bochs config files
* boot/ - 2nd stage bootloader
* boot0/ - 1st stage bootloader
* data/ - datafiles (font-file and fill.asm)
* fs/	- file system related source
* kernel/ - kernel source
* lib/ - some helper sources and includes
* release/ - latest release
* screenshots/ - latest screenshot
* tools/ - scripts and toos
* userspace/ - userspace related code


REFERENCES
==========

* http://www.brokenthorn.com/Resources/OSDev17.html
* http://www.jamesmolloy.co.uk/tutorial_html/9.-Multitasking.html
* http://pdos.csail.mit.edu/6.828/2011/labs/lab6/
* http://pdos.csail.mit.edu/6.828/2011/xv6.html
* http://www.nongnu.org/ext2-doc/
* http://www.osdever.net/tutorials/view/multiprocessing-support-for-hobby-oses-explained
* http://forum.osdev.org/viewtopic.php?f=1&t=10944
* http://wiki.osdev.org/Virtual_8086_Mode
* http://wiki.xomb.org/index.php?title=ACPI_Tables