Changes
/* FDC Track Format */
* There are 2 types of sectors based on their DATA AM value. Data sectors are marked by an FB byte, while deleted sectors are marked by an F8 byte.
* Gaps are necessary to accommodate variations in rotation speed between different drives and avoid overlapping.
At ~300 RPM, an MFM track contains about 6250 bytes (200 ms per track / 32 µs per byte).
In MFM (Modified Frequency Modulation) encoding, the IDAM and DATA AM are always preceded by three A1 bytes to help the FDC lock onto the data stream after a gap and accurately read the following datas. This is needed because MFM is more compact and harder to read than earlier encoding methods.
