======================
Deep OS - A preemptive multitasking unix-like OS, built from scratch
=====================

Authors: 
Jagat Sastry Pudipeddi
Alok Katiyar

Following are the features that our project supports:
  
Libc
--------
fork, exec, execve, execvpe, wait, waitpid, exit, getpid, open, close, read, opendir, readdir, closedir, sleep , printf, scanf (with multiple arguments), malloc, pwd, sleep

Binaries
--------
ls, cd, ps, sleep, dsh (shell), ulimit(-Sv)

Shell commands/Features
-----------------------
help
env
setenv (used for setting PATH)
cd
pwd
sh (alias for dsh)
Relative and absolute filename reference
Path based command execution
Background process (&)
Status bar that mentions uptime, current process, number of process

======================================
Building and Running
=====================================
The provided Makefile:
  1) builds a kernel
	2) copies it into rootfs/boot/kernel/kernel
	3) creates an ISO CD image with the rootfs/ contents

To boot the system in QEMU, run:
	qemu-system-x86_64 -curses -cdrom $USER.iso -drive id=disk,file=$USER.img,if=none -device ahci,id=ahci -device ide-drive,drive=disk,bus=ahci.0 -gdb tcp::NNNN

	Explanation of parameters:
	-curses         use a text console (omit this to use default SDL/VNC console)
	-cdrom x.iso    connect a CD-ROM and insert CD with x.iso disk
	-hda x.img      connect a hard drive with x.img disk
	-gdb tcp::NNNN  listen for "remote" debugging connections on port NNNN

When using the -curses mode, switch to the qemu> console with ESC-2.

To connect a remote debugger to the running qemu VM:
	gdb ./kernel
	target remote localhost:1234

====================
License/Attributions
====================
Released under BSD License.

This is a hobby/coursework OS and should be used only for learning purposes.

The following resources were used in building this OS. Some code snippets were adapted from the following tutorials and existing hobby OSes

Bootloader is from the existing FreeBSD source code

Online Tutorials
-----------------
James Molloy OS dev tutorial - http://jamesmolloy.co.uk/tutorial_html/index.html
Brans's Kernel dev tutorial - http://www.osdever.net/bkerndev/Docs/title.htm
Ian Jack's kernel dev tutorial - http://www.ijack.org.uk/
Broken Thorn kernel dev tutorial - http://www.brokenthorn.com/Resources/OSDevIndex.html
OS Development wiki - http://wiki.osdev.org/Expanded_Main_Page

Other OSes
-----------------
Geek OS - http://geekos.sourceforge.net/ (tarfs)
Shovel OS - https://code.google.com/p/shovelos/ (interrupts)
Minix 3 - https://github.com/minix3/minix

Books
-------------------
Understanding the Linux Kernel, Bovet et al
Linux Kernel Development, Robert Love
Design and Implementation of Operating Systems, Tanenbaum