Virtual Terminal management model
RFC 782

Document Type RFC - Unknown (January 1981; No errata)
Last updated 2013-03-02
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A Virtual Terminal Management Model

        RFC 782

        prepared for 

        Defense Communications Agency
        WWMCCS ADP Directorate
        Command and Control Technical Center
        11440 Isaac Newton Square
        Reston, Virginia 22090

        Jose Nabielsky
        Anita P. Skelton

        The MITRE Corporation
        MITRE C(3) Division
        Washington C(3) Operations
        1820 Dolley Madison Boulevard

                          TABLE OF CONTENTS


LIST OF ILLUSTRATIONS                                             vi

1.0  INTRODUCTION                                                  1
1.1  The Workstation Environment                                   1
1.2  Virtual Terminal Management                                   2
1.3  The Scope                                                     3
1.4  Related Work                                                  4

2.0  THE VTM MODEL                                                 5
2.1  The VTM Model Components                                      7
2.2  The Virtual Terminal Model                                   10
     2.2.1  Virtual Terminal Connectivity                         11
     2.2.2  Virtual Terminal Organization                         11
    The Virtual Keys                             12
    The Virtual Controller                       12
    The Virtual Display                          12
     2.2.3  Virtual Terminal Architecture                         13
    Communication Variables                      13
    Virtual Display with File Extension          13
    Virtual Display Windows                      14
2.3  The Workstation Model                                        17
     2.3.1  The Adaptation Unit                                   17
     2.3.2  The Executive                                         18

REFERENCES                                                        19


                        LIST OF ILLUSTRATIONS


Figure Number

     2.1       The Virtual Terminal Model                          7
     2.2       The Workstation Model                               8
     2.3       VT 0 (expanded from previous figure)                9
     2.4       The Domains                                        14



     Recent advances in micro-electronics have brought us to the  age
of the inexpensive, yet powerful, microprocessor.  Closely resembling
the advances of the 1960's which brought about  the  transition  from
batch  processing  to time-sharing, this technological trend suggests
the birth of decentralized architectures where the  processing  power
is  shifted  closer  to  the user in the form of intelligent personal
workstations.  The virtual terminal model described in this  document
caters to this anticipated personal computing environment.

1.1  The Workstation Environment

     A personal workstation is a computing engine which  consists  of
hardware  and  software dedicated to serve a single user.  As part of
its architecture, the workstation can invoke the resources of  other,
physically  separate  components, effectively extending this personal
environment well beyond the bounds of the single workstation.

     In this personal environment,  processing  resources  previously
shared  among  multiple  users  now become dedicated to a single one,
with a large part of these resources summoned to provide an effective
human-machine  interface.   As a consequence, modalities of input and
output that were unfeasible under the time-shared regime now become a
part of a conversational language  between user and workstation.  Due
to the availability of processing cycles, and the  closeness  of  the
user devices to these cycles, the workstation can support interactive
devices, and dialogue modes using these devices, which could  not  be
afforded before.

     The workstation can provide the  user  with  the  mechanisms  to
conduct  several  concurrent  conversations  with user-agents located
elsewhere in the global architecture.   One  such  mechanism  is  the
partitioning  of  the  workstation  physical  display  into  multiple
logical  displays,  with  one  or  more  of  these  logical  displays
providing a dedicated workspace between user and agent.

     The nature of the conversations on these logical  displays  need
not  be  limited  to  conventional  alphanumeric  input  and  output.
Conversations using input tools  such  as  positioning  and  pointing
devices  (e.g.,  mouse,  tablet, and such), and using high-resolution
graphics objects for output (e.g., line drawings, raster  blocks  and
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