Publication 1763-RM001B-EN-P - April 2007
Communications Instructions
359
Communication
Servicing Selection and
Message Servicing
Selection
The following screen shows the channel configuration window for
Communication Servicing Selection and Message Servicing Selection.
Communication Servicing Selection
Use the check box to enhance communication capability. If the check box
is unchecked, communication throughput (and scan time) will increase.
When Communications Servicing Selection is checked, at the next
execution of a Service Communications (SVC) instruction, I/O Refresh
(REF) instruction, or when it performs Communications Servicing,
whichever occurs first, commands/replies are processed as follows:
•
One incoming channel 0 or channel 1 command;
•
One incoming channel 0 or channel 1 message reply;
•
One outgoing channel 0 or channel 1 message on the overflow
queue.
When the Communications Servicing Selection bit is unchecked, at the
next execution of a Service Communications (SVC) instruction, I/O
Refresh (REF) instruction, or when it performs Communications Servicing,
whichever occurs first, commands/replies are processed as follows:
•
One incoming channel 0 or channel 1 command;
•
(conditional) If the Message Servicing Selection is clear (not
checked) first, all incoming channel 0 or channel 1 message replies;
then all outgoing channel 0 or channel 1 messages on the overflow
queue. If the Message Servicing Selection is set (checked), First the
incoming channel 0 or channel 1 message reply; then one outgoing
channel 0 or channel 1 message on the overflow queue.
•
All remaining incoming channel 0 or channel 1 commands.
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