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Windowing a Set of 3270 Multiple Logical Terminal Sessions

IP.com Disclosure Number: IPCOM000109988D
Original Publication Date: 1992-Oct-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 96K

Publishing Venue

IBM

Related People

Lection, DB: AUTHOR

Abstract

Computer terminals connected to a large IBM mainframe computer converse via the 3270 computer terminal emulation standard. The 3270 emulation standard is supported across several transmission topologies such as SDLC, Asynch, SNA, 802.2, and NETBIOS. The 3270 emulation is supported across these topologies in two modes DFT and CUT.

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Windowing a Set of 3270 Multiple Logical Terminal Sessions

       Computer terminals connected to a large IBM mainframe
computer converse via the 3270 computer terminal emulation standard.
The 3270 emulation standard is supported across several transmission
topologies such as SDLC, Asynch, SNA, 802.2, and NETBIOS.  The 3270
emulation is supported across these topologies in two modes DFT and
CUT.

      Distributed Function Terminal (DFT) mode is a mode of terminal
emulation that provides significant power within the intelligent
workstation acting as a 3270 emulator.  All 3270 order streams and
commands are interpreted, validated and executed at the intelligent
workstation.  A DFT emulation also has the capability to multiplex
several 3270 sessions at the intelligent workstation.

      Control Unit Terminal (CUT) mode is a more primitive and older
mode of 3270 terminal emulation.  The CUT mode terminal sends all
operator actions, key presses, etc., to a 3270 control unit for
processing.  The control unit validates the operator input and sends
subsequent commands back to the terminal to move the cursor, lock the
keyboard, or perform some other terminal task.

      CUT mode 3270 terminals were traditionally single session
terminals.  A later enhancement to the CUT mode technology called
Multiple Logical Terminal or MLT was introduced, and this allowed the
terminal to support up to 4 sessions.  These sessions were supported
by the control unit holding the session's images at the control unit,
and the operator could send a command to the control unit to switch
the active session at any time.

      CUT/MLT and DFT multiplexed terminal sessions differ widely.
The DFT session images exist in the intelligent workstation and are
managed by the intelligent workstation. DFT emulators take advantage
of this and are able to present the sessions to the operator in a
windowed format, or each full screen one at a time, with a key
sequence to switch to the next session.

      CUT/MLT multiplexed terminals to date have only provided full
screen sessions with a key sequence to switch to the next session.
This is because the 3270 control unit can only supply one session's
data at a given moment.

      With the introduction and widespread use of the Graphical User
Interface, or GUI, the CUT/MLT multiplexed terminal can be improved
to allow to the CUT/MLT sessions to me windowed.  This allows the...