AM3270/TR3271 Reference Manual

Details of the QUO Protocol
AM3270 Subdevice Protocols
4–20 086705 Tandem Computers Incorporated
Table 4-3 lists some of the error conditions that could occur during WRITE operations.
Table 4-3. PRT Protocol WRITE Errors
Operation/Error
Number Description Action/Indication
WRITE 123 Device Busy. Indicates that a WRITE
operation is in progress.
Retry the WRITE operation from
the application process.
WRITE 171 No Response. When the device was
selected, the cluster controller did not
respond.
Check the actual cluster
controller for an error condition.
WRITE 172 Improper Reply. The selected device
responded with an invalid control sequence.
Generally indicates a 3270
problem or a sequence of
problems with the
communications system.
WRITE 173 Text sent to the device was NAKed by the
device until the retry count was exhausted.
Generally indicates some part of
the communications system
(lines and modems) is not
working properly.
WRITE 180 Unknown device status received. An invalid 3270 device status
was received and could not be
translated into a usable error
number. Use SCF to determine
the status received.
Details of the QUO
Protocol
The QUO protocol provides services to 327x terminals by way of Quotron
communications controllers. This protocol is used only in those environments that
have devices attached to a Quotron controller concentrator. The controller
concentrator multiplexes the messages that flow from many Quotron devices through
one logical AM3270 subdevice defined in the AM3270 I/O process.
Quotron devices are defined, monitored, and controlled through the SCF ADD SU and
SCF ALTER SU commands. CMI can not be used with Quotron devices.
Communication With
Quotron Devices
An application communicating with Quotron devices can run in either an IBM or a
Tandem host. If the application runs in an IBM host, the application must
communicate with AM3270 through TR3271. If the application runs in a Tandem
system, it can run either in the same system in which AM3270 runs, or in another
Tandem system.
The protocol control information passed between the application and the controller
concentrator is transparent to the AM3270 I/O process, including AM3270’s QUO
protocol module that provides the Guardian 90 file-system interface. This means that
the QUO protocol module of the AM3270 I/O process does not use the QUO protocol
control information to process the data. Only the controller concentrator and the
application use the QUO protocol information to process the data.