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mOS is the UNIX-like operating system developed from scratch and aims to be POSIX compliant.

• Filesystem
• Program loading
• UI (X11)
• Log
• Networking
• Signal
• Terminal
• mOS toolchain
• Port figlet
• Libc
• Port GNU Bash, Coreutils
• Unit testing
• Dynamic linker
• Port GCC (the GNU Compiler Collection)
• Browser
• Sound
• Symmetric multiprocessing

🍀 Optional features

• Setup 2-level paging in boot.asm

MacOS

• install packages

  $ brew install qemu nasm gdb i386-elf-gcc i386-elf-grub bochs e2fsprogs xorriso

• open your bash config and add lines below. Depending on your bash config, the file might be different. I useohmyzsh, so it is.zshrc

  # .zshrcalias grub-file=i386-elf-grub-filealias grub-mkrescue=i386-elf-grub-mkrescue

• run emulator

  $ cd src && mkdir logs$ ./create_image.sh && ./build.sh qemu iso

• open another terminal

  $ cd src$ gdb isodir/boot/mos.bin# in gdb(gdb) target remote localhost:1234(gdb) c

✍🏻 If you get this errorhdiutil: attach failed - no mountable file systems, installingextFS for MAC might help

Ubuntu

• Install packakges

  $ sudo apt install build-essential autopoint bison gperf texi2html texinfo qemu automake-1.15 nasm xorriso qemu-system-i386

• Install gcc cross compilier viahttps://wiki.osdev.org/GCC_Cross-Compiler#The_Build

• Install GCC (Version 9.1.0) & Binutils (Version 2.32).

• Open src/toolchain/build.sh and modify SYSROOT and PREFIX variables to fit in your case

  PREFIX="$HOME/opt/cross"TARGET=i386-pc-mos# SYSROOT cannot locate inside PREFIXSYSROOT="$HOME/Projects/mos/src/toolchain/sysroot"JOBCOUNT=$(nproc)

• Install mos toolchain

  $ cd src/toolchain$ ./build.sh

• Run Emulator

  $ cd src && mkdir logs$ ./create_image.sh$ cd ports/figlet && ./package.sh && cd ../..$ cd ports/bash && ./package.sh make && cd ../..$ cd ports/coreutils && ./package.sh make && cd ../..$ ./build.sh qemu iso

• Open another terminal

  $ cd src$ gdb isodir/boot/mos.bin# in gdb(gdb) target remote localhost:1234(gdb) c

✍️ To get userspace address for debugging

$ i386-mos-readelf -e program# find the line below and copy Addr# [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al# [ x] .text             PROGBITS        xxx      xxx    xxx    00 AX   0   0  4

Unit Test

$ cd test && git clone https://github.com/ThrowTheSwitch/Unity.git unity$ make clean && make

Debugging

inbuild.sh, adding-s -S right afterqemu to switch to debug mode. Currently, I use vscode +native debug -> click Run -> choose "Attach to QEMU"

Monitoring

by default, mOS logs output to terminal. If you want to monitor via file, doing following steps

# src/build.sh#L71-serial stdio↓-serial file:logs/uart1.log

$ tail -f serial.log | while read line ; do echo $line ; done

✍🏻 Usingtail in pipe way to color the output (like above) causes a delay -> have to manually save in the IDE to get latest changes

• http://www.brokenthorn.com/Resources
• http://www.jamesmolloy.co.uk/tutorial_html/
• https://wiki.osdev.org

• Understanding the Linux Kernel, 3rd Edition by Daniel P. Bovet; Marco Cesati