Initial commit: Alpine Zero-OS initramfs build system with cleaned Docker configuration

2025-08-15 22:11:44 +02:00
commit 9b14d94bbe
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+# Minimal Embedded Initramfs Design
+
+## 🎯 **Requirements: Ultra-Minimal Embedded CPIO**
+
+- **Size Target**: 50-100MB (not 700MB!)
+- **Network drivers** + essential firmware only
+- **eudev** for module loading
+- **btrfs** and **vfat** filesystem support
+- **Embedded in kernel** for fastest boot
+
+## 📦 **Minimal Package List**
+
+### Core System (Essential Only)
+```
+alpine-baselayout     # Basic filesystem structure
+busybox              # Essential utilities
+musl                 # C library
+```
+
+### Module Loading & Hardware Detection
+```
+eudev                # Hardware detection and module loading
+kmod                 # Module management
+```
+
+### Filesystem Support (Minimal)
+```
+btrfs-progs          # btrfs filesystem support  
+dosfstools           # vfat filesystem support
+```
+
+### Network Essentials (Minimal)
+```
+# NO full linux-firmware (600MB!)
+# Only essential network drivers via selective firmware
+```
+
+## 🗂️ **Firmware Strategy: Selective Loading**
+
+Instead of 600MB linux-firmware package:
+
+### Essential Network Firmware Only
+```
+intel/          # Intel ethernet (e1000e, ixgbe, i40e)
+realtek/        # Realtek ethernet (r8169)  
+broadcom/       # Broadcom ethernet (bnx2, tg3)
+```
+
+### Load via Kernel Modules (Not Initramfs)
+- WiFi firmware (loaded later from RFS)
+- GPU firmware (not needed for initramfs)
+- Sound firmware (not needed)
+
+## 🎯 **Size Optimization Strategy**
+
+### What to EXCLUDE from Initramfs
+- ❌ **SSH tools** (700KB) - load from RFS
+- ❌ **Debugging tools** (gdb, strace, etc. - 50MB)
+- ❌ **Development tools** (python, etc. - 50MB) 
+- ❌ **Full linux-firmware** (600MB) - selective only
+- ❌ **Compression tools** (load from RFS)
+- ❌ **Network utilities** (curl, wget, etc.)
+
+### What to INCLUDE in Initramfs
+- ✅ **Core Alpine base** (~10MB)
+- ✅ **eudev + kmod** (~5MB)
+- ✅ **Essential network drivers** (~20MB firmware)
+- ✅ **btrfs-progs + dosfstools** (~10MB)
+- ✅ **GitHub components** (zinit, etc. ~5MB)
+
+**Target: ~50MB total**
+
+## 🔧 **Implementation Changes Needed**
+
+### 1. Create Minimal Package List
+Replace `packages.txt` with ultra-minimal version
+
+### 2. Selective Firmware Installation
+Custom script to install only essential network firmware:
+- `/lib/firmware/intel/`
+- `/lib/firmware/realtek/` 
+- `/lib/firmware/broadcom/`
+
+### 3. Build Process Changes
+- Skip massive firmware installation
+- Strip unnecessary files aggressively
+- Optimize cpio compression
+
+### 4. Two-Stage Loading
+1. **Initramfs**: Minimal (network + filesystems)
+2. **RFS**: Full tooling loaded after network
+
+## 📊 **Expected Size Breakdown**
+
+| Component | Size | Notes |
+|-----------|------|-------|
+| Alpine base | ~10MB | Core system |
+| eudev + kmod | ~5MB | Module loading |
+| Filesystems | ~10MB | btrfs + vfat |
+| Network firmware | ~20MB | Essential only |
+| GitHub tools | ~5MB | zinit, core-x, etc |
+| **Total** | **~50MB** | **10x smaller!** |
+
+## 🚀 **Benefits of Minimal Approach**
+
+- **Fast boot**: 50MB vs 700MB embedded
+- **Memory efficient**: Less RAM usage
+- **Network focused**: Only what's needed for connectivity
+- **Scalable**: Load additional tools from RFS after network
+
+This aligns with the original Zero-OS philosophy: minimal initramfs + network-loaded tools.