Embrace extreme minimalism - cut everything unnecessary

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>
2026-04-24 13:45:02 +00:00 · 2025-12-28 17:48:51 +00:00
parent 9a2ec2c753
commit 012327c7e7
6 changed files with 477 additions and 207 deletions
--- a/README.md
+++ b/README.md
@@ -1,8 +1,25 @@
 # MetalOS

-A minimal operating system built from the ground up to run QT6 applications on AMD64 hardware with Radeon RX 6600 GPU and UEFI boot.
+**The most minimal OS possible that runs QT6 Hello World.**

-**Not Linux. Not BSD. Not Windows.** Just enough OS to run a QT6 Hello World full-screen application.
+Not Linux. Not BSD. Not Windows. Just enough code to boot, initialize GPU, and run one app.
+
+## Extreme Minimalism
+
+MetalOS is an exercise in **absolute minimalism**:
+
+- ❌ **No scheduler** - one app = always running
+- ❌ **No process management** - one process only
+- ❌ **No file system** - app embedded in boot image
+- ❌ **No networking** - not needed
+- ❌ **No shell/command line** - boot directly to app
+- ❌ **No security** - trust everything
+- ❌ **No multi-core** - one CPU core
+- ❌ **No dynamic linking** - static link everything
+
+**If it doesn't help QT6 Hello World run, it doesn't exist.**
+
+Target: **< 200 KB OS code** (excluding QT6 itself)

 ## Project Status

@@ -12,7 +29,23 @@ Currently: Project structure, documentation, and skeleton code in place.

 ## What is MetalOS?

-MetalOS is a **minimal, purpose-built operating system** with a single goal: demonstrate that you can build a custom OS from scratch to run modern GUI applications (specifically QT6).
+MetalOS is **the smallest possible operating system** that can boot QT6 Hello World on specific hardware.
+
+### Philosophy
+
+Every feature must answer: **"Does this help run QT6 Hello World?"**
+
+If no → it doesn't exist.
+
+### Aggressive Minimalism
+
+- **Bootloader**: < 10 KB (just load kernel and jump)
+- **Kernel**: < 100 KB (memory, interrupts, drivers)
+- **GPU Driver**: < 50 KB (minimal display init)
+- **Input Drivers**: < 20 KB (keyboard + mouse only)
+- **Total OS**: ~200 KB
+
+Compare to Linux kernel: ~30 MB. We're **150x smaller** by doing only one thing.

 ### Key Features

@@ -82,10 +115,13 @@ See [docs/BUILD.md](docs/BUILD.md) for instructions on creating a bootable USB d

 ## Documentation

- **[ARCHITECTURE.md](docs/ARCHITECTURE.md)** - System design and architecture
- **[BUILD.md](docs/BUILD.md)** - Build instructions and dependencies
- **[DEVELOPMENT.md](docs/DEVELOPMENT.md)** - Development workflow and guidelines
- **[ROADMAP.md](docs/ROADMAP.md)** - Development phases and timeline
+- **[MINIMALISM.md](docs/MINIMALISM.md)** - ⭐ **START HERE** - Philosophy and what we cut
+- **[ARCHITECTURE.md](docs/ARCHITECTURE.md)** - System design (minimal version)
+- **[ROADMAP.md](docs/ROADMAP.md)** - Development phases
+- **[BUILD.md](docs/BUILD.md)** - Build instructions
+- **[DEVELOPMENT.md](docs/DEVELOPMENT.md)** - Development workflow
+- **[COMPONENTS.md](docs/COMPONENTS.md)** - Component checklist
+- **[STATUS.md](docs/STATUS.md)** - Current implementation status

 ## Project Structure

@@ -116,13 +152,13 @@ See [docs/ROADMAP.md](docs/ROADMAP.md) for detailed breakdown.

 ## Why?

-**Learning**: Building an OS from scratch is the ultimate systems programming education.
+**Minimalism**: How small can an OS be and still run GUI apps?

-**Minimal Design**: Modern OSes are complex. This project asks: "What's the absolute minimum needed for a GUI application?"
+**Learning**: Building an OS from scratch is the ultimate systems programming challenge.

-**Custom Hardware**: Show that you can optimize an OS for specific hardware instead of supporting everything.
+**Proof of Concept**: Modern frameworks like QT6 can run on tiny custom OSes.

-**QT6 Demo**: Prove that modern application frameworks can run on custom OS implementations.
+**Fun**: Because we can.

 ## Technology Stack

@@ -142,15 +178,22 @@ See [docs/ROADMAP.md](docs/ROADMAP.md) for detailed breakdown.

 ## Contributing

-This is primarily a learning/demonstration project, but contributions are welcome!
+**Golden Rule**: If it doesn't help QT6 Hello World, don't add it.

-**Guidelines**:
- Keep it minimal - every feature must justify its existence
- Document your changes
- Follow existing code style
- Test on QEMU before submitting
+Contributions welcome for:
+- Simplifying existing code (make it smaller!)
+- Bug fixes
+- GPU driver work (hardest part)
+- QT6 port work
+- Documentation

-See [docs/DEVELOPMENT.md](docs/DEVELOPMENT.md) for details.
+Not welcome:
+- Adding features "for completeness"
+- POSIX compatibility
+- Supporting other hardware
+- Generalizing anything
+
+See [CONTRIBUTING.md](CONTRIBUTING.md) and [docs/MINIMALISM.md](docs/MINIMALISM.md).

 ## License

--- a/bootloader/src/main.c
+++ b/bootloader/src/main.c
@@ -1,12 +1,13 @@
 /*
 * MetalOS UEFI Bootloader
 * 
- * This is a minimal UEFI bootloader that:
- * 1. Initializes graphics output
- * 2. Loads the kernel from disk
- * 3. Retrieves memory map and system information
- * 4. Exits boot services
- * 5. Transfers control to kernel
+ * MINIMAL bootloader:
+ * 1. Get framebuffer from UEFI
+ * 2. Load kernel blob from disk
+ * 3. Exit boot services
+ * 4. Jump to kernel
+ * 
+ * That's it. No fancy stuff.
 */

 #include "bootloader.h"
@@ -116,46 +117,35 @@ EFI_STATUS efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE* SystemTable) {
    gST = SystemTable;
    
    // Print banner
-    print_string(u"MetalOS Bootloader v0.1.0\r\n");
-    print_string(u"=========================\r\n\r\n");
+    print_string(u"MetalOS v0.1 - MINIMAL BOOTLOADER\r\n");
+    print_string(u"==================================\r\n\r\n");
    
-    // Initialize graphics
-    print_string(u"Initializing graphics...\r\n");
+    // Get framebuffer (don't care about resolution, take what UEFI gives us)
+    print_string(u"Getting framebuffer...\r\n");
    status = initialize_graphics(ImageHandle);
-    print_status(u"Graphics initialization", status);
    if (status != EFI_SUCCESS) {
-        print_string(u"WARNING: Graphics initialization failed, continuing...\r\n");
+        print_string(u"WARNING: No graphics, continuing anyway...\r\n");
    }
    
-    // Load kernel
+    // Load kernel (just read metalos.bin, don't overthink it)
    print_string(u"Loading kernel...\r\n");
    status = load_kernel(ImageHandle);
-    print_status(u"Kernel load", status);
    if (status != EFI_SUCCESS) {
-        print_string(u"ERROR: Failed to load kernel\r\n");
+        print_string(u"ERROR: Can't load kernel\r\n");
        return status;
    }
    
-    // Get ACPI information
-    print_string(u"Retrieving ACPI tables...\r\n");
-    boot_info.rsdp = get_rsdp();
+    // Get memory map (minimal info)
+    print_string(u"Getting memory map...\r\n");
+    // TODO: GetMemoryMap
    
-    // Get memory map
-    print_string(u"Retrieving memory map...\r\n");
-    // TODO: Call GetMemoryMap
-    
-    // Exit boot services
-    print_string(u"Exiting boot services...\r\n");
-    // TODO: Call ExitBootServices
+    // Exit boot services (point of no return)
+    print_string(u"Exiting UEFI boot services...\r\n");
+    // TODO: ExitBootServices
    
    // Jump to kernel
-    print_string(u"Starting kernel...\r\n");
+    // TODO: ((void(*)(BootInfo*))KERNEL_LOAD_ADDRESS)(&boot_info);
    
-    // TODO: Call kernel entry point with boot_info
-    // typedef void (*KernelEntry)(BootInfo*);
-    // KernelEntry kernel = (KernelEntry)KERNEL_LOAD_ADDRESS;
-    // kernel(&boot_info);
-    
-    // If we get here, something went wrong
+    // Should never get here
    return EFI_SUCCESS;
 }
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -6,10 +6,10 @@ MetalOS is a ground-up operating system designed specifically to run QT6 applica

 ## Design Principles

-1. **Minimal by Design**: Only implement what's necessary to run QT6 applications
+1. **Absolute Minimum**: If it's not needed for QT6 Hello World, it doesn't exist
 2. **UEFI Native**: Boot directly via UEFI, no legacy BIOS support
-3. **Hardware Specific**: Optimized for AMD64 + Radeon RX 6600
-4. **Modern Approach**: Learn from Linux but implement cleanly from scratch
+3. **Hardware Specific**: AMD64 + Radeon RX 6600 only - no abstractions for other hardware
+4. **Single Purpose**: One app, one GPU, one goal - nothing else matters

 ## System Architecture

@@ -54,13 +54,13 @@ MetalOS is a ground-up operating system designed specifically to run QT6 applica
  - Transfer control to kernel

 ### 2. Kernel Core
- **Purpose**: Provide essential OS services
- **Language**: C/C++ with assembly for low-level operations
+- **Purpose**: Absolute bare minimum OS services
+- **Language**: C with assembly for critical parts
 - **Subsystems**:
-  - Memory Management (physical/virtual)
-  - Process/Thread Scheduler
-  - Interrupt Handling
-  - System Call Interface
+  - Memory Management (just enough for app + QT6)
+  - Single process support (no scheduler needed!)
+  - Interrupt handling (only what GPU/input needs)
+  - Direct syscall to kernel functions (no table/dispatch overhead)

 ### 3. Hardware Abstraction Layer (HAL)
 - **Purpose**: Abstract hardware specifics
@@ -78,28 +78,29 @@ MetalOS is a ground-up operating system designed specifically to run QT6 applica
  - QT6 framework (statically linked into application)
  - No shell, no command line - direct boot to app

-## Memory Layout
+## Memory Layout (Simplified)

 ```
 0x0000000000000000 - 0x0000000000000FFF : NULL guard page
-0x0000000000001000 - 0x00000000000FFFFF : Bootloader code/data
-0x0000000000100000 - 0x00000000FFFFFFFF : Kernel space
-0x0000000100000000 - 0x00007FFFFFFFFFFF : User space
-0xFFFF800000000000 - 0xFFFFFFFFFFFFFFFF : Kernel heap/stacks
+0x0000000000001000 - 0x00000000000FFFFF : Bootloader (temporary)
+0x0000000000100000 - 0x0000000000FFFFFF : Kernel (small!)
+0x0000000001000000 - 0x00000000FFFFFFFF : Application + QT6
+GPU VRAM: Separate, mapped via BAR
 ```

-## Boot Process
+No complex memory regions - keep it simple!

-1. **UEFI Firmware** loads bootloader from EFI System Partition
-2. **Bootloader** initializes basic hardware and sets up memory
-3. **Bootloader** locates and loads kernel binary
-4. **Bootloader** exits UEFI boot services
-5. **Kernel** initializes subsystems (memory, scheduler, interrupts)
-6. **Kernel** loads HAL drivers (GPU, PCI, input)
-7. **Kernel** directly launches QT6 Hello World application (no shell, no init)
-8. **Application** runs full-screen until exit/reboot
+## Boot Process (Minimal)

-**Note**: No command line, no shell - the system boots directly into the single application.
+1. **UEFI Firmware** loads bootloader
+2. **Bootloader** gets framebuffer, loads kernel, jumps
+3. **Kernel** maps memory, enables interrupts
+4. **Kernel** initializes GPU (minimal)
+5. **Kernel** sets up input (keyboard/mouse only)
+6. **Kernel** jumps directly to QT6 app
+7. **App** runs until halt
+
+**That's it. No filesystem, no daemons, no services, no nothing.**

 ## Development Phases

--- a/docs/MINIMALISM.md
+++ b/docs/MINIMALISM.md
@@ -0,0 +1,225 @@
+# MetalOS - Extreme Minimalism Guide
+
+## What ABSOLUTE MINIMUM Means
+
+We're not building a general-purpose OS. We're building **the smallest possible software layer** that lets QT6 Hello World run on AMD64 + RX 6600.
+
+## Cut Everything
+
+### ❌ NO Scheduler
+- **Why not?**: One app = one process = always running
+- **Instead**: Direct execution, no context switching
+- **Saves**: Scheduler code, process queues, timer interrupts for scheduling
+
+### ❌ NO Process Management
+- **Why not?**: Only one process ever exists
+- **Instead**: App runs in ring 0 (kernel mode) or simple ring 3 with static setup
+- **Saves**: Process structures, fork/exec, process lifecycle
+
+### ❌ NO File System
+- **Why not?**: Everything loaded at boot
+- **Instead**: App binary embedded in boot image or loaded by bootloader once
+- **Saves**: VFS, inode structures, file descriptors, read/write/open/close
+
+### ❌ NO Networking
+- **Why not?**: Hello World doesn't need network
+- **Instead**: Nothing
+- **Saves**: TCP/IP stack, network drivers, sockets
+
+### ❌ NO Security
+- **Why not?**: Single app, demo system
+- **Instead**: Trust everything
+- **Saves**: Permissions, user/group IDs, capabilities, security modules
+
+### ❌ NO Virtual Memory (maybe)
+- **Why not?**: Could run everything with identity mapping
+- **Instead**: Simple page tables just to keep CPU happy
+- **Saves**: TLB management, page fault handling, swapping
+
+### ❌ NO Dynamic Linking
+- **Why not?**: Complexity nightmare
+- **Instead**: Static link everything into one blob
+- **Saves**: ELF loader complexity, PLT/GOT, symbol resolution at runtime
+
+### ❌ NO Multi-core
+- **Why not?**: One app on one core is plenty
+- **Instead**: Use only bootstrap processor (BSP)
+- **Saves**: SMP initialization, locks, atomic operations, IPI handling
+
+### ❌ NO ACPI (mostly)
+- **Why not?**: Complex and usually not needed for basic operation
+- **Instead**: Minimal ACPI just for GPU if absolutely required
+- **Saves**: AML interpreter, ACPI tables parsing, power management
+
+### ❌ NO Signals/IPC
+- **Why not?**: One process = nobody to talk to
+- **Instead**: Nothing
+- **Saves**: Signal handling, pipes, message queues, shared memory
+
+### ❌ NO Timers (mostly)
+- **Why not?**: QT6 needs *some* time, but minimal
+- **Instead**: Simple timer for QT event loop only
+- **Saves**: Complex timer infrastructure, high-resolution timers
+
+## What We MUST Keep (Absolute Minimum)
+
+### ✅ Memory Allocator
+- **Why**: QT6 needs malloc/free
+- **Minimum**: Simple bump allocator or basic free list
+- **No need for**: Fancy algorithms, defragmentation, memory pools
+
+### ✅ Interrupts
+- **Why**: Keyboard/mouse input, timer for QT
+- **Minimum**: 
+  - Keyboard interrupt
+  - Mouse interrupt  
+  - Timer interrupt (for QT event loop)
+  - GPU interrupt (if needed)
+- **That's it!** Maybe 4-5 interrupt handlers total
+
+### ✅ GPU Driver
+- **Why**: Need to display graphics
+- **Minimum**:
+  - Initialize display pipeline
+  - Set up framebuffer
+  - Blit pixels to screen
+- **No need for**: 3D acceleration, multiple displays, hot-plug
+
+### ✅ Input Drivers
+- **Why**: Need keyboard/mouse for QT events
+- **Minimum**:
+  - USB XHCI (or PS/2 if simpler!)
+  - HID keyboard
+  - HID mouse
+- **No need for**: Other USB devices, complex HID parsing
+
+### ✅ PCI Enumeration
+- **Why**: Find the GPU
+- **Minimum**: 
+  - Scan bus for our specific GPU
+  - Enable memory/IO access
+- **No need for**: Full PCI tree, hot-plug, PCI-to-PCI bridges
+
+### ✅ System Calls (bare minimum)
+- **Why**: User space needs to talk to kernel
+- **Minimum**:
+  - `write()` - for debugging output
+  - `mmap()` - for memory
+  - `ioctl()` - for GPU/input
+  - Maybe 5-10 syscalls total
+- **No need for**: POSIX compatibility, 300+ syscalls
+
+## Radical Simplifications
+
+### Framebuffer Over Everything
+- **Skip**: Complex GPU 3D acceleration
+- **Use**: Direct framebuffer blitting
+- **QT6**: Can render to memory, we copy to VRAM
+- **Trade-off**: Slower but WAY simpler
+
+### Identity Mapping (maybe)
+- **Skip**: Complex virtual memory
+- **Use**: Physical = Virtual (or simple offset)
+- **Note**: x86-64 requires paging enabled, but can be trivial
+
+### PS/2 Over USB
+- **Skip**: Complex USB stack if possible
+- **Use**: PS/2 keyboard/mouse if hardware supports
+- **Simpler**: Direct port I/O vs USB protocol
+
+### Polling Over Interrupts (where possible)
+- **Skip**: Complex interrupt handling
+- **Use**: Poll for events in tight loop
+- **Trade-off**: CPU usage vs complexity
+
+### Hardcode Everything
+- **Skip**: Configuration files, boot parameters
+- **Use**: Compiled-in constants
+- **Examples**: 
+  - Screen resolution: 1920x1080 (hardcoded)
+  - GPU PCI ID: hardcoded
+  - Memory layout: hardcoded
+
+## Code Size Targets
+
+Aim for **minimal code size**:
+
+- **Bootloader**: < 10 KB
+- **Kernel**: < 100 KB
+- **GPU Driver**: < 50 KB (hardest part)
+- **Input Drivers**: < 20 KB
+- **QT6 + App**: ~10-20 MB (unavoidable - QT is big)
+
+**Total OS (without QT)**: ~200 KB or less!
+
+## Performance Targets
+
+We don't care about performance, we care about **working**:
+
+- Boot time: Don't care (< 30 seconds is fine)
+- Frame rate: Don't care (30 FPS is plenty)
+- Memory usage: Don't care (512 MB is plenty)
+- CPU usage: Don't care (can peg one core)
+
+**Trade complexity for simplicity every time.**
+
+## Implementation Strategy
+
+### Phase 1 ✅ (Done)
+- Project structure
+- Documentation
+
+### Phase 2 (Bootloader)
+- UEFI console output (for debugging)
+- Load kernel blob
+- Jump to kernel
+- **Skip**: Complex file systems, just load from known location
+
+### Phase 3 (Kernel)
+- Set up page tables (minimal)
+- Set up interrupts (only what we need)
+- Memory allocator (simple bump allocator)
+- **Skip**: Complex memory management
+
+### Phase 4 (GPU)
+- PCI scan for RX 6600
+- Enable BAR
+- Initialize display (hardcode 1920x1080)
+- Framebuffer blit
+- **Skip**: Everything else GPU can do
+
+### Phase 5 (Input)
+- Try PS/2 first (simpler!)
+- If not available, minimal USB XHCI
+- Keyboard scancodes -> QT key events
+- Mouse packets -> QT mouse events
+- **Skip**: Complex HID parsing, other devices
+
+### Phase 6 (QT6)
+- Port minimal QT6 (Core + Gui + Widgets only)
+- QPA plugin: just framebuffer blit + input events
+- Static link everything
+- **Skip**: All optional QT modules
+
+### Phase 7 (Integration)
+- Link app with QT6
+- Embed in boot image
+- Test and debug
+- **Skip**: Anything that doesn't work - iterate
+
+## When in Doubt
+
+Ask these questions:
+
+1. **Does Hello World need this?** No → Cut it
+2. **Can we hardcode this?** Yes → Hardcode it
+3. **Can we do this simpler?** Yes → Do it simpler
+4. **Does Linux do it complex?** Yes → Do it simpler anyway
+
+## Bottom Line
+
+**Build the smallest possible OS that boots QT6 Hello World.**
+
+If it doesn't directly contribute to that goal, it doesn't exist.
+
+No compromises. Maximum minimalism.
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -2,9 +2,11 @@

 ## Vision

-MetalOS is a **minimal operating system** built from the ground up with a single purpose: run a QT6 Hello World application full-screen on AMD64 hardware with a Radeon RX 6600 GPU, booting via UEFI.
+MetalOS is **the absolute minimum operating system** needed to boot QT6 Hello World on AMD64 + RX 6600 via UEFI.

-This is not a general-purpose OS. Every component is purpose-built to achieve this specific goal with minimal complexity.
+**Target**: < 200 KB of OS code (excluding QT6)
+
+**Philosophy**: If it doesn't directly enable QT6 Hello World, it doesn't exist.

 ## Development Phases

@@ -28,145 +30,136 @@ This is not a general-purpose OS. Every component is purpose-built to achieve th

 ### Phase 2: UEFI Bootloader (Next)

-**Goal**: Boot from UEFI and load kernel
+**Goal**: Load kernel and jump (< 10 KB code)

 **Tasks**:
-1. Implement UEFI protocol interfaces
-   - Console I/O for early debugging
-   - Graphics Output Protocol
-   - Simple File System Protocol
-   - Memory allocation
+1. Console output for debugging (UEFI OutputString)
+2. Get framebuffer info from GOP (Graphics Output Protocol)
+3. Load kernel blob from known location
+4. Get minimal memory map
+5. Exit boot services
+6. Jump to kernel

-2. Graphics initialization
-   - Query available video modes
-   - Set optimal resolution (1920x1080 or best available)
-   - Set up framebuffer
+**Simplifications**:
+- Don't enumerate all video modes, take default
+- Don't parse filesystem, load from fixed location
+- Skip ACPI (try without it first)
+- No error recovery, just halt on failure

-3. Kernel loading
-   - Read metalos.bin from disk
-   - Load into memory at 1MB mark
-   - Verify kernel integrity
-
-4. System information gathering
-   - Get memory map
-   - Find ACPI tables (RSDP)
-   - Detect CPU features
-
-5. Exit boot services and jump to kernel
-   - Call ExitBootServices()
-   - Pass BootInfo structure to kernel
-   - Jump to kernel_main()
-
-**Success Criteria**: Bootloader loads kernel and jumps to kernel code
+**Success Criteria**: Bootloader prints messages and jumps to kernel

 ### Phase 3: Minimal Kernel

-**Goal**: Initialize hardware and provide basic services
+**Goal**: Initialize hardware (< 100 KB code)

 **Tasks**:
-1. Early kernel initialization
-   - Set up GDT (Global Descriptor Table)
-   - Set up IDT (Interrupt Descriptor Table)
-   - Enable interrupts
-   - Initialize framebuffer console
+1. Minimal paging setup
+   - Identity map or simple offset
+   - Just enough to keep CPU happy
+   - No fancy page fault handling

-2. Memory management
-   - Physical memory allocator (buddy system or bitmap)
-   - Virtual memory setup (page tables)
-   - Kernel heap allocator
-   - *Minimal implementation - just enough for QT6*
+2. Interrupt handling
+   - IDT with ~5 handlers max
+   - Timer, keyboard, mouse, GPU (if needed)
+   - No complex IRQ routing

-3. Process/Thread support
-   - Simple round-robin scheduler
-   - Context switching (bare minimum)
-   - Single user process support
-   - *No multi-user, no fancy scheduling*
+3. Memory allocator
+   - Bump allocator or simple free list
+   - No fancy algorithms
+   - Just malloc/free for QT6

-4. Basic I/O
-   - Serial port for debugging
-   - Framebuffer console
-   - *No disk I/O needed initially*
+4. NO scheduler - one process, always running
+5. NO process management - app is statically linked with kernel or simple jump

-**Success Criteria**: Kernel boots, prints messages, can allocate memory
+**Simplifications**:
+- Skip GDT setup if not needed (UEFI might have set it up)
+- Identity mapping instead of complex virtual memory
+- Bump allocator instead of buddy/slab
+- No TLB shootdown, no page fault handling

-### Phase 4: Hardware Abstraction Layer
+**Success Criteria**: Kernel boots, prints messages, mallocs work

-**Goal**: Support minimal hardware needed for QT6
+### Phase 4: Hardware Support
+
+**Goal**: GPU + Input (< 70 KB code)

 **Tasks**:
-1. PCI Bus enumeration
-   - Scan PCI devices
-   - Find Radeon RX 6600 GPU
-   - Basic configuration
+1. PCI scan (minimal)
+   - Hardcode scan for vendor 0x1002 (AMD)
+   - Find RX 6600 device ID
+   - Enable memory access
+   - That's it!

-2. GPU Driver (Radeon RX 6600)
-   - Initialize GPU
-   - Set up display pipeline
-   - Configure framebuffer
-   - *Minimal - no 3D acceleration initially*
-   - *Can use reference from Linux amdgpu driver*
+2. GPU Driver (hardest part, < 50 KB)
+   - Map MMIO registers
+   - Initialize display controller (DCN)
+   - Hardcode 1920x1080 mode
+   - Set up framebuffer in VRAM
+   - Enable display output
+   - *Study Linux amdgpu driver, but keep it simple*

-3. Input devices
-   - USB HID keyboard support
-   - USB HID mouse support
-   - PS/2 fallback (if needed)
-   - *Just enough for QT event handling*
+3. Input devices (< 20 KB)
+   - **Try PS/2 first** (much simpler than USB!)
+   - If no PS/2: minimal USB XHCI for HID
+   - Keyboard: scancode → QT key events
+   - Mouse: packets → QT mouse events

-4. Timer
-   - APIC timer or PIT
-   - For scheduling and timeouts
+**Simplifications**:
+- No PCI tree traversal, just scan for our GPU
+- No GPU 3D, just 2D framebuffer
+- No hot-plug, no multiple displays
+- PS/2 over USB if possible (way simpler)
+- No timer sophistication, PIT is fine

-**Success Criteria**: Can detect and initialize GPU, receive keyboard/mouse input
+**Success Criteria**: Display working, keyboard/mouse input working

-### Phase 5: System Call Interface
+### Phase 5: Minimal Syscalls

-**Goal**: Provide user-kernel boundary
+**Goal**: User-kernel boundary (< 10 KB code)

 **Tasks**:
-1. System call mechanism
-   - syscall/sysret instructions
-   - System call table
-   - Parameter passing
+1. Syscall mechanism (syscall/sysret or just direct calls)
+2. Maybe 5-10 syscalls total:
+   - write() - debugging
+   - mmap() / munmap() - memory
+   - ioctl() - device control
+   - poll() - wait for input events
+   - exit() - halt system

-2. Essential system calls
-   - exit() - terminate process
-   - write() - output to console/log
-   - mmap() - memory allocation
-   - open/read/close() - minimal file operations (if needed)
-   - ioctl() - device control (for GPU)
-   - poll/select() - event handling (for input)
+**Simplifications**:
+- No syscall table if app can directly call kernel functions
+- No parameter validation (trust everything)
+- No error handling (just panic)

-3. User-kernel transitions
-   - Ring 3 to Ring 0 transitions
-   - Parameter validation
-   - Error handling
+**Success Criteria**: App can call kernel functions

-**Success Criteria**: User space can make system calls
+### Phase 6: User Space & Application

-### Phase 6: User Space Runtime
-
-**Goal**: Support C++ applications
+**Goal**: Load and run app

 **Tasks**:
-1. ELF loader
-   - Parse ELF headers
-   - Load program segments
-   - Set up entry point
-   - *Static linking initially - no dynamic loader*
+1. Simple app loading
+   - Static-linked binary
+   - No ELF parsing if we can avoid it
+   - Just jump to known entry point

-2. Minimal C/C++ runtime
-   - _start() function
-   - C++ global constructors/destructors
-   - Memory allocation (malloc/free)
-   - Basic string functions
-   - *Only what QT6 needs*
+2. C++ minimal runtime
+   - Global constructors
+   - Basic new/delete (use kernel malloc)
+   - No exceptions (disable them)

-3. Application launcher (no init/shell needed)
-   - Directly load QT6 hello world application
-   - No command line, no shell
-   - Single application until reboot
+3. Direct boot to app
+   - No init, no shell
+   - Kernel calls app's main() directly
+   - App exits → kernel halts

-**Success Criteria**: Can load and run the QT6 hello world application directly
+**Simplifications**:
+- Static link everything into one blob
+- Skip ELF loader completely if possible
+- No exceptions (compile with -fno-exceptions)
+- App runs in ring 0 or simple ring 3
+
+**Success Criteria**: Can run simple C++ program

 ### Phase 7: QT6 Port

--- a/kernel/src/main.c
+++ b/kernel/src/main.c
@@ -1,8 +1,9 @@
 /*
 * MetalOS Kernel - Main Entry Point
 * 
- * Minimal kernel implementation for running QT6 applications.
- * Only implements what's absolutely necessary.
+ * EXTREME MINIMAL kernel - only what's needed for QT6 Hello World.
+ * No scheduler, no process management, no filesystem, no nothing.
+ * Just: boot -> init GPU -> init input -> run app.
 */

 #include "kernel/kernel.h"
@@ -11,6 +12,9 @@
 /*
 * Kernel main entry point
 * Called by bootloader with boot information
+ * 
+ * This is it. The entire OS. No scheduler, no processes, no filesystem.
+ * Just set up hardware and jump to the QT6 app.
 */
 void kernel_main(BootInfo* boot_info) {
    // Initialize basic console output using framebuffer
@@ -22,41 +26,55 @@ void kernel_main(BootInfo* boot_info) {
    );
    
    console_clear();
-    console_print("MetalOS Kernel v0.1.0\n");
-    console_print("=====================\n\n");
+    console_print("MetalOS v0.1 - MINIMAL\n");
+    console_print("======================\n\n");
    
-    console_print("Initializing minimal kernel...\n");
+    // TODO: Set up minimal page tables (identity mapped or simple offset)
+    console_print("[ ] Memory (identity map)\n");
    
-    // TODO: Initialize memory management
-    console_print("[ ] Memory management\n");
+    // TODO: Set up IDT with only interrupts we need:
+    //       - Keyboard/mouse (USB or PS/2)
+    //       - Timer (for QT event loop)
+    //       - GPU (if needed)
+    //       That's it! Maybe 5 interrupt handlers total.
+    console_print("[ ] Interrupts (minimal)\n");
    
-    // TODO: Initialize interrupt handling
-    console_print("[ ] Interrupt handling\n");
+    // TODO: Simple memory allocator (bump allocator is fine)
+    console_print("[ ] Heap (bump allocator)\n");
    
-    // TODO: Initialize PCI bus
-    console_print("[ ] PCI enumeration\n");
+    // TODO: Find RX 6600 GPU via PCI (hardcode vendor/device ID)
+    console_print("[ ] PCI (find GPU only)\n");
    
-    // TODO: Initialize GPU driver
-    console_print("[ ] GPU driver (Radeon RX 6600)\n");
+    // TODO: Initialize GPU - minimal
+    //       - Enable BAR
+    //       - Init display pipeline
+    //       - Set up framebuffer at 1920x1080 (hardcoded)
+    console_print("[ ] GPU (RX 6600, 1920x1080)\n");
    
-    // TODO: Initialize input devices
-    console_print("[ ] Input devices\n");
+    // TODO: Initialize input
+    //       Try PS/2 first (simpler!)
+    //       Fall back to minimal USB XHCI if needed
+    console_print("[ ] Input (PS/2 or USB)\n");
    
-    // TODO: Setup system calls
-    console_print("[ ] System call interface\n");
+    // TODO: Jump directly to QT6 Hello World app
+    //       No shell, no init, no fork/exec
+    //       Just: jump to application entry point
+    console_print("[ ] Jump to QT6 app\n");
    
-    // TODO: Load and run QT6 hello world application directly (no shell/init)
-    console_print("[ ] Loading QT6 Hello World application...\n");
+    console_print("\nBooting app...\n");
    
-    console_print("\nKernel initialization complete.\n");
-    console_print("Booting directly into application (no shell)...\n");
+    // TODO: Replace this with jump to QT6 app
+    // For now, halt
+    console_print("ERROR: App not linked yet\n");
    
-    // TODO: Jump to QT6 hello world application entry point
-    // The application will run full-screen until exit
-    // No shell, no command line - just the one app
-    
-    // Halt - in real implementation, we'd start the application
    while(1) {
        __asm__ volatile("hlt");
    }
 }
+
+/*
+ * That's the entire kernel. No scheduler. No processes. No filesystem.
+ * Just boot, initialize hardware, run app.
+ * 
+ * Total kernel size target: < 100 KB
+ */