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.

10_devices/scsi.md

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+[← Home](../README.md) · [Devices](README.md)
+
+# scsi.device — Hard Disk I/O
+
+## Overview
+
+SCSI and IDE hard disks are accessed via `scsi.device` (A3000/A4000 built-in) or `2nd.scsi.device` / `ide.device` (A1200/A600). The API is the same as trackdisk for basic read/write, with additional SCSI direct commands.
+
+---
+
+## Opening
+
+```c
+struct IOStdReq *scsi = CreateStdIO(port);
+OpenDevice("scsi.device", 0, (struct IORequest *)scsi, 0);
+/* unit 0 = first SCSI/IDE device */
+```
+
+---
+
+## Standard Commands
+
+Same as trackdisk: `CMD_READ`, `CMD_WRITE`, `CMD_UPDATE`, `TD_CHANGENUM`, etc.
+
+---
+
+## Direct SCSI Commands (HD_SCSICMD)
+
+```c
+struct SCSICmd scsicmd;
+UBYTE cdb[10];    /* SCSI CDB */
+UBYTE sense[20];  /* sense data buffer */
+UBYTE data[512];  /* data buffer */
+
+/* Read 1 sector at LBA 0: */
+cdb[0] = 0x28;    /* READ(10) */
+cdb[1] = 0;
+cdb[2] = 0; cdb[3] = 0; cdb[4] = 0; cdb[5] = 0;  /* LBA = 0 */
+cdb[6] = 0;
+cdb[7] = 0; cdb[8] = 1;  /* transfer length = 1 sector */
+cdb[9] = 0;
+
+scsicmd.scsi_Data      = (UWORD *)data;
+scsicmd.scsi_Length     = 512;
+scsicmd.scsi_Command    = cdb;
+scsicmd.scsi_CmdLength  = 10;
+scsicmd.scsi_Flags      = SCSIF_READ;
+scsicmd.scsi_SenseData  = sense;
+scsicmd.scsi_SenseLength = sizeof(sense);
+
+scsi->io_Command = HD_SCSICMD;
+scsi->io_Data    = &scsicmd;
+scsi->io_Length  = sizeof(scsicmd);
+DoIO((struct IORequest *)scsi);
+
+if (scsicmd.scsi_Status != 0) {
+    /* SCSI error — check sense data */
+}
+```
+
+---
+
+## References
+
+- NDK39: `devices/scsidisk.h`
+- ADCD 2.1: scsi.device autodocs