# What is this?
This is a simple implementation of a computer kernel<br/>
written in pure x86 assembly with features including 
- Read/Write disk operations
- The ability to boot from the BIOS using the [JazzOS Bootloader](https://raw.githubusercontent.com/scprogramming/JazzOS/refs/heads/main/src/bootloader/boot.asm)
- A modified [MikeOS BASIC interpreter](https://mikeos.sourceforge.net/handbook-appdev-basic.html)
- A functional POSIX inspired CLI

# What is it for?
This project is aimed at people wanting to learn<br/>
more about kernels and low level system functionality.<br/>
In order to help with comprehension, there are a lot<br/>
of inline comments descibing what each part does.

# Commands
- CAT <filename>: outputs the contents of the file.
- LS: outputs a list of files on the system .
- CLEAR: clears the screen.
- REBOOT: reboots the system, this can also be done with [esc].
- BAS <filename>: runs a basic script.

# Running it
In order to build this project on a Linux system run<br/>
the following commands.
```
git clone https://git.javalsai.tuxcord.net/deadvey/crawos.git
cd crawos
sudo make
```
This will create a directory called 'disk_images' which<br/>
contains optical and floppy images that can be ran in a<br/>
virtual machine such as QEMU with
```
qemu-system-i386 -drive file=disk_images/crawos.img,if=floppy,format=raw
```
Or it can be burnt to a physical disk to be booted from<br/>
hardware.

# Development
In order to run this project in testing mode you can use<br/>
The 'test-linux.sh' bash script which will assemble and<br/>
boot the virtual machine (QEMU) for testing purposes.<br/>
```
./test-linux.sh
```
This will dump the contents of memory in /dev/shm/qemu-ram<br/>
To allow for easier debugging.

# BASIC development
Please refer to the [MikeOS BASIC documentation](https://mikeos.sourceforge.net/handbook-appdev-basic.html)<br/>
docs on writing BASIC code. In order to create new<br/>
files, place them in the /data/ directory, note the file<br/>
names are limited to 11 characters due to FAT12 limitations<br/>
(8 for the name and 3 for the extension).