Pros of blog_os

• More comprehensive documentation and detailed explanations
• Regular updates and active community engagement
• Broader coverage of OS development topics

Cons of blog_os

• Slower development pace compared to intermezzOS
• Less focus on specific architectural choices

Code Comparison

blog_os:

#[no_mangle]
pub extern "C" fn _start() -> ! {
    println!("Hello World{}", "!");
    loop {}
}

intermezzOS:

#[no_mangle]
pub extern fn kmain() -> ! {
    let hello = b"Hello World!";
    let color_byte = 0x1f; // white foreground, blue background

    let mut hello_color = [color_byte; 24];

    for (i, char_byte) in hello.into_iter().enumerate() {
        hello_color[i * 2] = *char_byte;
    }

    let buffer_ptr = (0xb8000 + 1988) as *mut _;
    unsafe { *buffer_ptr = hello_color };

    loop { }
}

Both projects aim to create operating systems in Rust, but they differ in their approach and focus. blog_os provides a more educational experience with detailed explanations, while intermezzOS offers a more hands-on approach with less documentation. The code comparison shows that blog_os uses a higher-level abstraction for printing, while intermezzOS demonstrates low-level memory manipulation for displaying text.

Pros of Theseus

• More active development with recent commits and releases
• Extensive documentation and research papers available
• Larger community and contributor base

Cons of Theseus

• More complex architecture and steeper learning curve
• Requires more system resources due to its advanced features
• Less beginner-friendly compared to intermezzOS

Code Comparison

intermezzOS kernel:

#[no_mangle]
pub extern fn kmain() -> ! {
    vga::clear_screen();
    println!("Hello, world!");
    loop { }
}

Theseus:

#[no_mangle]
pub extern "C" fn kernel_main() -> ! {
    println!("Hello from Theseus!");
    scheduler::schedule();
    loop { }
}

Both kernels use Rust and have similar entry points, but Theseus demonstrates more advanced features like a scheduler right from the start.

Pros of rust-raspberrypi-OS-tutorials

• More comprehensive and structured learning path for OS development on Raspberry Pi
• Regularly updated with new tutorials and improvements
• Focuses on practical, hands-on experience with real hardware

Cons of rust-raspberrypi-OS-tutorials

• Specific to Raspberry Pi architecture, limiting broader OS development concepts
• May be overwhelming for absolute beginners due to its depth and complexity
• Requires physical Raspberry Pi hardware for full experience

Code Comparison

rust-raspberrypi-OS-tutorials:

#[no_mangle]
pub extern "C" fn kernel_main() -> ! {
    // Initialization code
    loop {
        cortex_a::asm::wfe()
    }
}

intermezzOS/kernel:

#[no_mangle]
pub extern fn kmain() -> ! {
    // Initialization code
    loop {
        unsafe { asm!("hlt"); }
    }
}

Both projects use Rust for OS development, but rust-raspberrypi-OS-tutorials is tailored for Raspberry Pi, while intermezzOS/kernel is more generic. The code snippets show similar kernel entry points, but with platform-specific differences in the main loop implementation.

rust-raspberrypi-OS-tutorials offers a more structured learning experience with a focus on practical, hardware-specific knowledge. intermezzOS/kernel provides a more general approach to OS development, potentially offering broader conceptual understanding but with less hands-on application for specific hardware.

Pros of rCore

• Written in Rust, providing memory safety and concurrency benefits
• More comprehensive OS implementation with support for multiple architectures
• Active development with regular updates and contributions

Cons of rCore

• Higher complexity and steeper learning curve for beginners
• Larger codebase, which may be overwhelming for those new to OS development
• Requires more resources to build and run compared to simpler kernels

Code Comparison

rCore (main.rs):

#[no_mangle]
pub extern "C" fn rust_main() -> ! {
    println!("Hello, rCore!");
    panic!("Shutdown machine!");
}

intermezzOS (src/arch/x86_64/boot.asm):

global start
extern long_mode_start

section .text
bits 32
start:
    mov esp, stack_top
    call check_multiboot
    call check_cpuid
    call check_long_mode

Summary

rCore is a more feature-rich and actively developed OS project written in Rust, offering better safety guarantees and multi-architecture support. However, it may be more challenging for beginners due to its complexity. intermezzOS, while simpler and potentially easier to understand, has a more limited scope and fewer features. The choice between the two depends on the developer's goals and experience level in OS development.

Pros of Redox

• More mature and feature-rich operating system project
• Written in Rust, offering memory safety and concurrency benefits
• Active community with regular updates and contributions

Cons of Redox

• Larger codebase, potentially more complex for newcomers
• Steeper learning curve due to its more comprehensive nature
• May require more resources to build and run

Code Comparison

Redox (syscall handling):

pub fn syscall(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize) -> usize {
    let mut ret: usize;
    unsafe {
        asm!("int 0x80"
             : "={rax}"(ret)
             : "{rax}"(a), "{rbx}"(b), "{rcx}"(c), "{rdx}"(d), "{rsi}"(e), "{rdi}"(f)
             : "memory", "cc"
             : "intel", "volatile");
    }
    ret
}

intermezzOS (basic kernel entry):

#[no_mangle]
pub extern fn kmain() -> ! {
    vga::clear_screen();
    vga::print_hello();
    loop { }
}

The code snippets showcase the difference in complexity and focus between the two projects. Redox demonstrates a more advanced syscall handling mechanism, while intermezzOS presents a simpler kernel entry point, reflecting its educational nature.

Pros of Kerla

• Written in Rust, providing memory safety and modern language features
• More actively maintained with recent commits and updates
• Includes a broader range of kernel features and device support

Cons of Kerla

• More complex codebase, potentially harder for beginners to understand
• Requires more system resources due to its comprehensive feature set
• Less focused on educational purposes compared to intermezzOS

Code Comparison

Kerla (memory management):

pub fn alloc_pages(order: usize) -> Option<PhysAddr> {
    FRAME_ALLOCATOR.lock().alloc_pages(order)
}

intermezzOS (memory management):

pub fn allocate_frame() -> Option<Frame> {
    FRAME_ALLOCATOR.lock().allocate_frame()
}

Both projects use Rust for memory management, but Kerla's implementation appears more flexible with the order parameter for allocating multiple pages.

Summary

Kerla is a more feature-rich and actively maintained kernel project, while intermezzOS focuses on simplicity and education. Kerla may be better suited for advanced users or those interested in a more complete kernel implementation, whereas intermezzOS could be more appropriate for beginners or educational purposes.