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75 lines
1.9 KiB
Markdown
75 lines
1.9 KiB
Markdown
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[← Home](../README.md) · [Devices](README.md)
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# trackdisk.device — Floppy Disk I/O
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## Overview
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`trackdisk.device` provides raw sector I/O for Amiga floppy drives. Each drive is a unit (0–3). The device operates on 512-byte sectors, 11 sectors per track (880 KB DD disks) or 22 per track (1760 KB HD).
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---
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## Opening
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```c
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struct IOExtTD *tdreq = (struct IOExtTD *)
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CreateIORequest(port, sizeof(struct IOExtTD));
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OpenDevice("trackdisk.device", 0, (struct IORequest *)tdreq, 0);
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```
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---
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## Commands
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| Code | Constant | Description |
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|---|---|---|
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| 2 | `CMD_READ` | Read sectors |
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| 3 | `CMD_WRITE` | Write sectors |
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| 4 | `CMD_UPDATE` | Flush write buffer to disk |
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| 9 | `TD_MOTOR` | Turn motor on/off |
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| 10 | `TD_FORMAT` | Low-level format track |
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| 11 | `TD_SEEK` | Move head to track |
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| 12 | `TD_REMOVE` | Notify on disk change |
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| 13 | `TD_CHANGENUM` | Get disk change count |
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| 14 | `TD_CHANGESTATE` | Check if disk present |
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| 15 | `TD_PROTSTATUS` | Check write-protect |
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| 16 | `TD_RAWREAD` | Read raw MFM data |
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| 17 | `TD_RAWWRITE` | Write raw MFM data |
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| 18 | `TD_GETDRIVETYPE` | Get drive type |
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| 19 | `TD_GETNUMTRACKS` | Get total tracks |
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| 20 | `TD_ADDCHANGEINT` | Add disk change interrupt |
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| 21 | `TD_REMCHANGEINT` | Remove disk change interrupt |
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---
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## Reading a Sector
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```c
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UBYTE buf[512];
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tdreq->iotd_Req.io_Command = CMD_READ;
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tdreq->iotd_Req.io_Data = buf;
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tdreq->iotd_Req.io_Length = 512;
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tdreq->iotd_Req.io_Offset = 0; /* byte offset = sector * 512 */
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DoIO((struct IORequest *)tdreq);
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```
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---
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## Disk Geometry
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| Parameter | DD (880 KB) | HD (1760 KB) |
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|---|---|---|
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| Heads | 2 | 2 |
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| Cylinders | 80 | 80 |
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| Sectors/track | 11 | 22 |
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| Bytes/sector | 512 | 512 |
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| Total sectors | 1760 | 3520 |
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Byte offset = `(cylinder * 2 + head) * sectors_per_track * 512 + sector * 512`
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---
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## References
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- NDK39: `devices/trackdisk.h`
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- ADCD 2.1: trackdisk.device autodocs
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