TS/MP Pathsend and Server Programming Manual (H06.05+, J06.03+)

is up again, the new communication channel is established and the send2 operation is
successfully completed.
• The application uses only waited context-free sends.
After the first send operation (send1), the ACS subsystem goes down in a processor and is
not up again before the next send operation (send2). The send1 operation successfully
completes without any cause. When the send2 operation is initiated, TS/MP detects a problem
with the existing communication channel to the ROUT process. It closes the old faulty channel
with the ROUT process and tries to reopen it. Because the ROUT process is still down, the new
communication channel is not established, and the send2 operation fails with Pathsend error
947 (FESCLINKMONCONNECT) and file-system error 14 (FENOSUCHDEV). This is a transient
error. The send operation will be successful when the ACS subsystem automatically restarts.
The application program must retry the send operation till it succeeds.
• The application uses only nowaited context-free sends.
Assume that the application issues 10 nowaited sends and the ACS subsystem goes down in
a processor before it issues the AWAITIOX procedure. At this point, the ACS subsystem
automatically restarts. The application now issues the AWAITIOX procedure (and subsequent
FILEINFO) five times. It issues another nowaited send. The application issues the CANCELREQ
procedure for the remaining five sends. Finally, it issues one more nowaited send.
The first 10 nowait sends are successfully initiated without any cause. It means that they do
not return any error and will be outstanding until the AWAITIOX or CANCELREQ procedure
is called. Because the ACS subsystem restarts when the application issues the AWAITIOX
procedure (and FILEINFO procedure), it indicates that the sends have failed with file-system
error 201 (FEPATHDOWN).
Therefore, the application must complete (by calling the AWAITIOX procedure) or cancel (by
calling the CANCELREQ procedure) all the outstanding nowait sends, before issuing any new
nowait sends. If, as in this scenario, the application incorrectly issues another nowaited send
before completing or canceling all the outstanding nowait sends, the new nowait send initiation
will fail with Pathsend error 947 (FESCLINKMONCONNECT) and file-system error 201
(FEPATHDOWN).
After all the outstanding nowait sends are completed or canceled, if the application issues
another nowaited send, TS/MP closes the old faulty channel with the ROUT process and tries
to reopen it. In this example, because the ROUT process is restarted, the new communication
channel will be successfully established; this send and the subsequent sends will be successful.
• The application uses only nowaited context-free sends.
Assume that the application issues 10 nowaited sends and the ACS subsystem goes down in
a processor before it issues the AWAITIOX procedure. The application issues the AWAITIOX
procedure (and the subsequent FILEINFO procedure) five times. It then issues another nowaited
send. The application issues the CANCELREQ procedure for the remaining five sends. Finally,
it issues one more nowaited send.
The nowaited send is issued before the CANCELREQ procedure fails with Pathsend error 947
(FESCLINKMONCONNECT) and file-system error 201 (FEPATHDOWN), because the ACS
subsystem goes down. After all the outstanding nowait sends are completed or canceled,
when a new nowaited send is issued, TS/MP closes the old faulty channel with the ROUT
process and tries to reopen it. However, in this example, because the ROUT process is still
down at this point, the new communication channel will not be established, and the nowait
send will fail with Pathsend error 947 (FESCLINKMONCONNECT) and file-system error 14
(FENOSUCHDEV).
Basic Pathsend Programming 55