MascOS

16-bit Real Mode operating system made entirely in Assembly.

Current situation of the project

MascOS was built by me when I was 16 years old so expect bad code/bugs/bad practices. I no longer actively work on this project so don't expect anything new coming.

Other MS DOS programs can theoretically run on this not so good operating system, but keep in mind not everything needed has been implemented for those programs to behave without issues or run at all.

I have tried to boot MascOS from a floppy disk(3.5 inch, 1.44MB) and it worked almost flawlessly. It was tested on a Toshiba NB250 laptop.

If you want to learn how to create program for MascOS check the documentation.

Why MascOS

It's a learning project. I thought creating an operating system that targets old hardware would be a fun experiment to do.

Running the operating system

The operating system .flp image is called MascOS.flp and it's present in the files of this repository.
To run the os GNUmakefile assumes you have Qemu installed on your system.

To launch the os in a VM(Qemu) use:

shCopy
make run

It uses PulseAudio to emulate the pc speaker, so if you're having troubles to run the operating system use this command instead:

shCopy
qemu-system-i386 -fda MascOS.flp -M smm=off -no-shutdown -no-reboot \
	-cpu 486 -rtc base=localtime,clock=host

If you want to run this on real hardware you need a computer with legacy BIOS and not a modern UEFI system, since MascOS aims to run on old hardware.

Compiling

You must have NASM installed(assembler).

To compile the os just run:

shCopy
sudo make

You need administrator permission because GNUmakefile mounts the os image to /mnt/floppy so it can copy necessary files to the .flp image.

If you want to remove all compiled files:

shCopy
make clean

Troubleshooting

1. Why does the text in the edit program blink?

The VGA driver disables bliking to allow to use all 16 colors for background on real VGA hardware. Unfortunately on simulated VGA this doesn't work, and the text blinks.