5250 sessions hanging

We have a - lets call it mature - order entry program used every day by
several hundred people.

As far as I can tell, with no program changes we have started experiencing
the following error condition.

After all the data is entered and verified, control is passed to a
processing program which displays a message like -
"printout in process Ticket-xxxx Invoice-xxxx"
and then processes the ticket or invoice data, prints the documents,
updates the files, etc.

the lines of the program that display the message are (in debug mode)
Display Module
Source

Program: OE02CLE Library: MIS_LIB Module:
OE02CLE
2610 2609 C* DISPLAY IN PROCESS MESSAGE
2611 2610 C EXCEPT SCRMS1

10520 10519 OOE02CFM E
SCRMS1
10521 10520 O K8 'MESSAGE
'
10522 10521 O 24
'PRINTOUT IN
10523 10522 O 34 'TICKET-
'
10524 10523 O DSTKT# 42 ' -
'
10525 10524 O 54
'INVOICE- '
10526 10525 O DSUINV 62 ' -
'
10527 10526 O 75
'OE02C'

The entire display file looks like this
A DSPSIZ(*DS3
*DS4)
A USRDSPMGT CHGINPDFT
INDARA
A*-------------------------------------------------------------------
A R
MESSAGE
A
DSPMOD(*DS3)
A
PRINT(*PGM)
A
INVITE
A
SLNO(24)
A
CLRL(01)
A
OVERLAY
A
ALWROL
A CF01 CF02 CF03 CF04 CF05 CF06
CF07
A CF08 CF09 CF10 CF11 CF12 CF13
CF14
A CF15 CF16 CF17 CF18 CF19 CF20
CF21
A CF22 CF23
CF24
A ROLLUP ROLLDOWN CLEAR HLPRTN
HOME
A
HELP
A MSG1 78 O 1 2DSPATR(RI)

ok - it really has been a long time. the last time this display file was
changed was 02/13/91.

the display file was compiled with dfrwrt(*no)

starting last friday, once about once every 10,000 times the program is
called, the program hangs on debug line 10526 and stops processing . I
get this info from the dspjob call stack. The terminal displays - X
SESSION at the bottom left of the display. I can't start a service
program on it because it times out. This seems odd too. There are no
locks stopping the program.

This program has been in production for over 25 years.

the client is a client access session running under terminal services.

I really don't understand the details of 5250 communications but -
is it possible that this is some state issue where the session receives
the format, displays the format, but does not return info that the format
was displayed to the program?

Any thoughts or wild ideas appreciated.

Jim Horn

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