MiniOS - Custom Terminal Operating System in C

Overview

MiniOS is a small Track B project: a terminal-based mini operating system written in C. It uses five custom libraries for string handling, math, memory, screen output, and keyboard input, then combines them into a shell with a virtual file system and a cooperative scheduler.

What it demonstrates

• Custom string, math, memory, screen, and keyboard libraries
• A non-blocking shell loop
• In-memory virtual files backed by the custom allocator
• A background scheduler task that keeps running while the shell stays usable
• Terminal output and input handled without string.h, math.h, malloc, or free

How it works

The flow is simple and easy to explain in evaluation:

1. Keyboard reads user input.
2. Parser splits the line into command and arguments.
3. Shell decides which command to run.
4. Memory allocates or frees file data.
5. Math helps with arithmetic and boundary checks.
6. Screen prints the final result to the terminal.

Commands

Command	Description
help	Show available commands
echo <text...>	Print text
math <a> <op> <b>	Arithmetic using +, -, *, /
touch <file>	Create a file in virtual memory
write <file> <data...>	Write or overwrite file contents
read <file>	Read a file from virtual memory
ls	List all files with sizes
delete <file>	Delete a file and free its memory
run	Run one scheduler tick
mem	Show virtual memory usage
clear	Clear the terminal and restart the banner
exit	Quit MiniOS

Build and Run

make
./miniOS

Optional cleanup:

make clean

Submission Notes

• This project follows Track B: Mini Operating System.
• Files are stored only in RAM, so they reset when the program closes.
• The scheduler is cooperative, not preemptive.
• The virtual RAM size is 1 MB.

Known Issues

• No persistent storage yet.
• No real multitasking or process isolation.
• Input handling is terminal-based, so it depends on a POSIX-like environment.

Demo Checklist

• help shows the full command list
• touch, write, read, ls, and delete work together
• run shows the background counter
• mem shows allocator usage
• clear redraws the boot banner cleanly