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Disc Format Block
Programmer's Reference Manuals
» Part 15 – SWI Calls
» FileCore
» FileCore_DiscFormat
» Disc Format Block
Disc Format Block
| Offset | Meaning |
|---|---|
| +0 | Sector size |
| +4 | Gap 1 side 0 |
| +8 | Gap 1 side 1 |
| +C | Gap 3 |
| +10 | Sectors per track |
| +11 | Density? |
| +12 | Options |
| +13 | Start sector on a track |
| +14 | Sector interleave |
| +15 | Side/side sector skew (signed) |
| +16 | Track/track sector skew (signed) |
| +17 | Sector fill value |
| +18 | Number of tracks to format (ie cylinders/drive: usually 80) |
| +1C-23 | Reserved, must be 0 |
| +24 | Sector ID buffer (1 word/sector) |
Format Options
| Bit | Meaning |
|---|---|
| 0 | Index mark required |
| 1 | Double step |
| 2 – 3 | 0 = Interleaved side |
| 1 = Format side 1 only | |
| 2 = Format side 2 only | |
| 3 = Sequenced sides | |
| 4 – 7 | Reserved, must be zero |
Sector ID Buffer
| Bit | Meaning |
|---|---|
| 0 – 7 | Cylinder number mod 256 |
| 8 – 15 | Head (0 onwards) |
| 16 – 23 | Sector number |
| 24 – 31 | Log2(sector size)-7 |