- Flushing write buffers failed if size of last written block
  is exactly 29696 bytes.
  (reported by Robert T. Harris <rth@sparta.com>)
- CPU timing dependent code calibrated at module load.
- Handle drives that do not support the report_drive_configuration
  command (reported by Paul Allen <paula@boeing.com>).
- Implemented recovery on write errors (needs some more testing).

