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WAIT time out

The WAIT signal present in each channel constitutes a potential problem. A defective peripheral could held that signal indefinitely causing the entire computer to freeze.

To prevent that, a time out of approximately 2 microseconds (32 clock periods) is put in place so if the WAIT signal is held by that long, the I/O operation is resumed and WAIT is ignored by other 2 microseconds.

When this anomaly occurs, a Fails condition is reported.