docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections

Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.

02_boot_sequence/dos_boot.md

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+[← Home](../README.md) · [Boot Sequence](README.md)
+
+# DOS Boot — Bootstrap, Mount List, Startup-Sequence
+
+## Overview
+
+After the Kickstart ROM initialises the kernel and resident modules, `dos.library` takes over to mount filesystems and run the user's startup scripts.
+
+---
+
+## Boot Sequence Flow
+
+```
+Kickstart ROM init complete
+    ↓
+dos.library creates initial CLI process
+    ↓
+BootStrap module (strap) reads boot block from boot device
+    ↓
+Boot block executed (OFS/FFS bootblock code)
+    ↓
+Mount configured devices from MountList (DEVS:DOSDrivers/)
+    ↓
+Execute S:Startup-Sequence
+    ↓
+Execute S:User-Startup
+    ↓
+LoadWB (start Workbench)
+```
+
+---
+
+## Boot Block Format
+
+The first 2 sectors (1024 bytes) of a bootable disk:
+
+```
+Offset   Size   Description
+$000     4      Boot block ID: "DOS\0" (OFS), "DOS\1" (FFS), etc.
+$004     4      Checksum (complement to zero)
+$008     4      Root block pointer (usually 880)
+$00C     ...    Boot code (up to 1012 bytes of 68000 code)
+```
+
+### Boot Block Types
+
+| ID | Hex | Type |
+|---|---|---|
+| `DOS\0` | `444F5300` | OFS (Old File System) |
+| `DOS\1` | `444F5301` | FFS (Fast File System) |
+| `DOS\2` | `444F5302` | OFS + International |
+| `DOS\3` | `444F5303` | FFS + International |
+| `DOS\4` | `444F5304` | OFS + Dir Cache |
+| `DOS\5` | `444F5305` | FFS + Dir Cache |
+| `DOS\6` | `444F5306` | OFS + Long Filenames (OS 3.2) |
+| `DOS\7` | `444F5307` | FFS + Long Filenames (OS 3.2) |
+
+---
+
+## Boot Priority
+
+Devices are booted in priority order. Highest priority device boots first:
+
+| Device | Default Priority | Description |
+|---|---|---|
+| DF0: | 5 | First floppy drive |
+| DH0: | 0 | First hard disk partition |
+| DH1: | −5 | Second partition |
+| DF1: | −10 | Second floppy |
+
+Set in mountlist: `BootPri = 0` or via HDToolBox.
+
+---
+
+## Startup-Sequence
+
+Standard `S:Startup-Sequence` for OS 3.1:
+
+```
+C:SetPatch QUIET            ; apply ROM patches
+C:AddBuffers DH0: 50         ; filesystem buffers
+C:Version >NIL:
+FailAt 21
+MakeDir RAM:T RAM:Clipboards RAM:ENV RAM:ENV/Sys
+Copy >NIL: ENVARC: RAM:ENV ALL NOREQ
+Assign >NIL: T: RAM:T
+Assign >NIL: CLIPS: RAM:Clipboards
+Assign >NIL: REXX: S:
+Assign >NIL: PRINTERS: DEVS:Printers
+Assign >NIL: KEYMAPS: DEVS:Keymaps
+Assign >NIL: LOCALE: SYS:Locale
+Assign >NIL: LIBS: SYS:Classes ADD
+Assign >NIL: HELP: LOCALE:Help DEFER
+
+C:IPrefs
+
+ConClip >NIL:
+; Launch Workbench:
+LoadWB
+EndCLI >NIL:
+```
+
+---
+
+## Early Startup Control (Boot Menu)
+
+Hold **both mouse buttons** during boot to access the Early Startup Control menu:
+
+| Option | Description |
+|---|---|
+| Boot With No Startup-Sequence | Skip S:Startup-Sequence |
+| Boot Standard | Normal boot |
+| Boot With: [device list] | Select boot device |
+| Display Mode: [NTSC/PAL] | Override display standard |
+
+---
+
+## References
+
+- RKRM: Boot chapter
+- NDK39: `dos/dosextens.h` — BootStrap