The actual sector size if the size code is 0, or the (ignored) value 0xFF for larger size codes.
The length of the gap 3 parameter for read/write operations.
The number of cylinders.
The transfer speed in kilobytes per second. Can be 250, 300, 500, or 1000, but each drive type only supports a subset of these values.
The number of heads.
The length of the gap 3 when formatting media.
The sector interleave to be applied when formatting. 0 means no interleave, 1 means 1:1 etc.
The offset of the sector numbers on side 2 (i.e., head number 1). Normally, sector numbering on both sides starts with 1.
A list from one of the following flag values:
Use MFM encoding.
Use FM (single-density) encoding.
Use 2 steps per each cylinder (for accessing 40-cylinder media in 80-cylinder drives).
Do not use 2 steps per cylinder, i.e., access each physical cylinder of the drive.
Use perpendicular recording (for 2.88 MB media, currently not supported).
Use longitudinal recording.
For any missing parameter, the current value will be used, so only actual changes need to be specified. Thus to turn off a flag bit (like +mfm which is the default for all drive types), the form with a leading minus sign must explicitly be used.