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 and operating system design.

We have (or had) 32-bit protected mode, interrupt handling, 
memory management, scheduling, a floppy disk controller, mouse 
as well as VESA and a couple of other things. networking is a big goal.

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

Copyright M.Idziorek 2014-2015,2018 <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.

Building
--------

Adapt $SYSROOT in userspace/sys/Makefile

Requirements:
    
* OS Specific Toolchain [1]

    binutils-*
    gcc-*

* Newlib * [2]

* GRUB2

https://wiki.osdev.org/GCC_Cross-Compiler
ftp://ftp.fu-berlin.de/unix/languages/gcc/releases/gcc-8.2.0/gcc-8.2.0.tar.gz
https://sunsite.icm.edu.pl/pub/gnu/binutils/binutils-2.31.1.tar.gz

https://wiki.osdev.org/Porting_Newlib
ftp://sourceware.org/pub/newlib/newlib-3.0.0.20180802.tar.gz
https://ftp.gnu.org/gnu/autoconf/autoconf-2.68.tar.gz
https://ftp.gnu.org/gnu/automake/automake-1.11.6.tar.gz

MAKE DIFF OF NEWLIB !

DID NO TRY YET
https://www.musl-libc.org/releases/musl-1.1.19.tar.gz

Usage
-----
Use the FoolOS.iso in your favourite emulator or `dd` to an usb stick 
and test on real hardware.

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 --with-term --enable-smp) (add -lpthread to LIBS in the Makefile!)
* bochs 2.6.8 (compiled with: ./configure --enable-clgd54xx --enable-a20-pin --enable-debugger --enable-disasm --enable-e1000 --with-x --with-x11 --with-term --enable-smp) (add -lpthread to LIBS in the Makefile!)
* qemu 1.1.2
* virtual box 4.1.18
* Acer Aspire 1810TZ (Notebook)
* Q6600 on Asus p5n32-e sli plus (Desktop PC)
* 4790K on Asus (Desktop PC)

Features
--------

Please note that all features are only very rudimentary and buggy.
Some might have been disable (temporarily) due to conflicts or regressions.

* ELF binaries
* PIT support / Timing
* PIC support & Interrupt handling framework
* Physical memory management
* Virtual memory management
* Multitasking
* Keyboard driver
* Spinlocks
* Simple Shell
* Simple Ext2 driver (read-only)

Fetures are under this line are currently disabled / not developed:

* Bootloader (2 stages)
* VESA Support
* PS2 Mouse driver
* Floppy disk driver
* ACPI / MP
* Symmetric Multiprocessing
* PCI bus scanning

Todos
-----

* Porting (ncurses, gcc, binutils, vim, apache...)
* Support some TTY standard (xterm)

* /dev/console 
* /dev/kb

* E1000 driver (or some other easy network card driver) maybe NS2000 better?
* Networking stack 

* GUI

Issues
------

* sbrk()
* ESP collisions!?
* TSS-ESP0?
* kbfree()
* pg_directory alloc 
* implement posix(?) getdents instead of our own readdir.
* Turning on some gcc optimizations breaks the kernel. (need debug so go for ELF!)
* Assumed support for VESA mode 0x114 with linear addressing. (let the user select)
* fixed size of process images!

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
* http://wiki.osdev.org/Hosted_GCC_Cross-Compiler
* https://sourceware.org/newlib/
* and many many more...