| Offset | Size | Description |
|---|---|---|
| 00 | byte | specify byte 1; step-rate time, head unload time |
| 01 | byte | specify byte 2; head load time, DMA mode |
| 02 | byte | timer ticks to wait before disk motor shutoff |
| 03 | byte | bytes per sector code: 0 - 128 bytes 1 - 256 bytes 2 - 512 bytes 3 - 1024 bytes |
| 04 | byte | sectors per track (last sector number) |
| 05 | byte | inter-block gap length/gap between sectors |
| 06 | byte | data length, if sector length not specified |
| 07 | byte | gap length between sectors for format |
| 08 | byte | fill byte for formatted sectors |
| 09 | byte | head settle time in milliseconds |
| 0A | byte | motor startup time in eighths of a second |