mirror of https://github.com/alfishe/amiga-bootcamp.git synced 2026-06-13 00:26:28 +00:00

Ilia Sharin 21751c0025 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.

2026-04-23 12:17:35 -04:00

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← Home · Boot Sequence

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:

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

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