Link transmission priority start.

摘要

In a link communications system or other such channel for conveying data, which system or channel includes error checking circuitry and protection from attempting communication through the link or channel when error conditions are indicated, a priority start technique allows use of the channel to convey error clearing routines or diagnostic data on the channel during such an error condition. The priority start technique attempts to force a start of transmission over the channel without reference to any of the protective features which would otherwise prevent a normal start command from being honoured. After encountering an error associated with the channel, tests are made to determine if the error is a normal error or an abnormal error. The recovery operation following a normal error ends with a normal channel start attempt. The recovery following an abnormal error includes the priority start which ignores the fact that the error would otherwise preclude starting the channel according to the normal channel start technique.