====== WDC1772 Data Access Framework Complete ======

//20 November 2004//

Disk access framework implemented.

To enhance performance, only events that can happen within the specific context (i.e. non generic) are processed. This divides access into the following different execution paths:

  - Read line is not connected to the FDC, which happens when no drive is selected. While the FDC halts on spin-up sequence early if this happens (since with drives deselected other lines are disconnected as well, like the index pulse that is used as a retry count by the FDC) it is possible to start and deselect a drive while in progress.
  - Read line is fed with random data, like on unformatted tracks, etc.
  - Read line is fed with real data from normal density tracks, that is, density does not change within a track.
  - Read line is fed with real data from variable density tracks, that is, density changes within a track.

Now (1) works.