Browse Prior Art Database

Automatic End On Condition Support for 3270 Device Emulation

IP.com Disclosure Number: IPCOM000120245D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 136K

Publishing Venue

IBM

Related People

Fix, GJ: AUTHOR [+2]

Abstract

A method for automatically ending 3270 Device Emulation is disclosed. The End emulation conditions (ENDCOND) parameter was added to the Start 3270 Display Emulation (STREML3270) and Start 3270 Printer Emulation (STRPRTEML) commands. The user can specify value(s) for the ENDCOND parameter that represent condition(s) on which the 3270 device emulation session is to automatically end.

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Automatic End On Condition Support for 3270 Device Emulation

      A method for automatically ending 3270 Device Emulation
is disclosed.  The End emulation conditions (ENDCOND) parameter was
added to the Start 3270 Display Emulation (STREML3270) and Start 3270
Printer Emulation (STRPRTEML) commands.  The user can specify
value(s) for the ENDCOND parameter that represent condition(s) on
which the 3270 device emulation session is to automatically end.

      This article describes AS/400* 3270 Device Emulation support
for ending a 3270 device emulation session automatically.
Previously, the user would have to interact with a keyboard and go
through one or more steps involving multiple keystrokes in order to
end the device emulation session.  These steps were eliminated with
the ENDCOND parameter.
AS/400 3270 Display Emulation:

      It is common for AS/400 systems to communicate with a host
system and for AS/400 display users to pass through to a host system
to run applications.  This is supported by an AS/400 operating system
component called 3270 Device Emulation (3270DE).

      NOTE:  The term 'host system' refers to a system that uses 3270
Data Stream Compatibility (DSC) to communicate with its displays
versus a 5250 data stream.

      The flow of data in this type of user environment is
illustrated in Fig. 1.

      In this environment, the AS/400 acts like a remote controller
to the IBM System/370 (S/370).  The S/370 application communicates
with 3270DE via a 3270 data stream. 3270DE translates this data
stream into a 5250 data stream when sending data outbound to the
display and vice versa when transmitting data inbound to the host
system.  This data stream translation enables the AS/400 user to run
host system applications.

      3270DE currently requires the user to do the following to end a
3270 display emulation session after logging off a host system
application:
1.  Press the Attention key to display a menu.
2.  Select a menu option to end the 3270 display emulation session.

      The ENDCOND parameter on the STREML3270 command will eliminate
these two steps required to end the session.  The user can specify
one or more of the following values for the ENDCOND parameter:
-  *DACTLU - 3270 display emulation will end when receiving a Systems
Network Architecture (SNA) Deactivate Logical Unit (DACTLU) command
from the host system.
-  *UNBIND - 3270 display emulation will end when receiving an SNA
UNBIND command from the host system.

      NOTE:  The DACTLU and UNBIND are common SNA commands sent by
the host system for either error conditions or for normal conditions,
such as when a user logs off a host system application.
      Here is a start 3270 display emulation example:
                STREML3270 EMLDEV(EMDSP01)
                ENDCOND(*UNBIND)

      After invoking this command, the user has just requested to
start a 3270 display emulat...