MancoOS - Educational Microkernel

MancoOS is a microkernel-based operating system designed for educational purposes. Built from scratch using C++17 and x86 Assembly, it emphasizes modularity, memory isolation, and a robust inter-process communication (IPC) system.

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System Evidence

IDT & Boot Sequence	SJF Scheduler Initialization
Kernel successfully loading the Interrupt Descriptor Table.	The SJF algorithm starting to manage system tasks.

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Architecture

Following the Minix philosophy, MancoOS keeps the Ring 0 (Kernel Space) as minimal as possible. Services such as video drivers and input handlers run in Ring 3 (User Space), communicating via a message-passing bus.

graph TD
    classDef userLayer fill:#E3F2FD,stroke:#1565C0,stroke-width:2px,color:#0D47A1
    classDef ipcLayer fill:#FFF3E0,stroke:#EF6C00,stroke-width:2px,stroke-dasharray: 5 5,color:#E65100
    classDef kernelLayer fill:#FFEBEE,stroke:#C62828,stroke-width:2px,color:#B71C1c

    subgraph Ring3 [Ring 3 - User Space]
        direction LR
        VD[VGA Service]:::userLayer
        KBD[Input Service]:::userLayer
        APP[Applications]:::userLayer
    end

    subgraph Bus [Inter-Process Communication]
        IPC{{Message Passing System}}:::ipcLayer
    end

    subgraph Ring0 [Ring 0 - Microkernel]
        direction LR
        SCHED[SJF Scheduler]:::kernelLayer
        MM[Memory Manager]:::kernelLayer
        ISR[Interrupt Handler]:::kernelLayer
    end

    VD <--> IPC
    KBD <--> IPC
    APP <--> IPC

    IPC <--> SCHED
    IPC <--> MM
    IPC <--> ISR

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Key Technical Features

• SJF Scheduler: Implements the Shortest Job First algorithm to minimize average waiting time, featuring assembly-level context switching.
• Physical Memory Manager (PMM): A high-performance memory allocator using a Bitmap structure to manage 4KB pages.
• Custom Visual Identity: A unique VGA color palette based on Rich Mahogany and Coffee Bean codes.
• Robust Exception Handling: Custom ISRs and IDT configuration to ensure system stability and prevent triple faults.
• Containerized Build System: A fully automated Docker pipeline for cross-compiling i386-elf binaries.

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How to Run

1. Build the ISO (Docker)

Ensure you have Docker installed and run the following command to generate the bootable image:

docker run --rm -v ${PWD}:/root/env microkernel-builder make iso

2. Execute via QEMU

You can run the OS locally or through a browser-based VNC container:

docker run -it --rm -p 8006:8006 -v ${PWD}:/storage -e BOOT="file:///storage/microkernel.iso" -e KVM=N qemux/qemu

Access the system at http://localhost:8006.

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Author

Developed by PedroVFSantos - Computer Science Student at UFSCar.