ISO 9040:1990
(Main)Information technology — Open Systems Interconnection — Virtual Terminal Basic Class Service
Information technology — Open Systems Interconnection — Virtual Terminal Basic Class Service
Technologies de l'information — Interconnexion des systèmes ouverts — Service de classe de base de terminal virtuel
General Information
Relations
Standards Content (Sample)
I N TE R NAT I O NA L IS0
STANDARD
First edition
1990-1 1 -1 5
I
Information technology - Open Systems
Interconnection - Virtual Terminal Basic Class
Service
Technologies de l'information - Interconnexion des systèmes ouverts - Service de
classe de base de terminal virtuel
r
Reference number
IS0 9040 : 1990 (E)
---------------------- Page: 1 ----------------------
IS0 9oQo : 1990 (E)
Contents
1 Scope . 1
2 Normative references . 1
3 Definitions . 2
3.1 Global OS1 definitions . 2
3.2 Association Control Selvice Element definMons . 2
2
3.3 Virtual Terminai Selvice definitions .
4 Abbreviations . 5
4.1 General . 5
4.2 Modes of operation . 5
4.3 WE model components . 5
4.4 Access-ruies . 5
5 Conventions . 6
6 General features . 6
6.1 Introduction . 6
6.2 Features of the Virtual Terminai Basic Class Service . 6
6.3 W Environment (WE) and WE-parameters . 6
6.4 Virtual Terminal Environment Profiles . 6
6.5 Dialogue Control . 6
7 Communication facilities . 7
7.1 Establishment faciiity . 7
7.2 Termination facility . 7
7.3 Negotiation facility . 7
7.4 Data Transfer faciiiiy . 7
7.5 Delivery Control facility . 7
7.6 Dialogue Management facility . 7
7.7 Interrupt facilities . 7
O is0 1990
Ali rights reserved . No part of this publication may be reproduced or utilized in any form or
by any means. electronic or mechanical. including photocopying and microfilm. without
permission In writing from the publisher .
international Organization for Standardization
Case Postale 56 CH-1211
Genève Switzerland
Printed in Switzerland
il
---------------------- Page: 2 ----------------------
8 Modes of operation . -7
8.1 S-mode . .7
8.2 &mode . .*.I
Q Access.rules .
10 functional units . 1.8
10.1 Negotiation functional units . n8
10.2 Negotiated Release functional Unit . 9
10.3 Urgent Data functional unit . 9
10.4 Breakfunctional unit . 9
10.5 Enhanced Access-rules functional unit . 9
10.6 Structured Control Objects functional unit . -10
10.7 Blocks functional unit . 10
10.8 Fields functional unit . 1 0
10.9 Reference Information Objects functional unit . 10
11 VT Environment Profiles (VTE-profiles) . -10
12 The VTE Model . 1 0
13 Display Objects . 12
13.1 Structure . 12
13.2 Attrlbutes . 15
14 Control Objects . 16
14.1 CO structure facilities and related restrictions .
16
14.2 Standard Control objects for fields and controlled data entry . 16
14.3 Standard control object for dynamic termination conditions . 17
14.4 Standard control object for notifying termination . 17
14.5 Standard control object for echo control . 17
15 Reference Information Objects . 17
15.1 Structure . 17
15.2 Generation and use of RiOs . 17
16 Device objects .
.18
17 WE Parameters and directed graph . 18
17.1 Directed graph of VTE-parameters . 18
17.2 VTE consistency rules . 18
18 Display Object WE-parameters . $21
18.1 Primary VTE-parameters . 21
18.2 Secondary VTE-parameters . 21
18.3 Tertiary VTE-parameter . 24
19 Operations on display objects . 25
................................... 25
19.1 Addressing operations
19.2 Update operations . 29
19.3 Access control over display object . 32
---------------------- Page: 3 ----------------------
IS0 9040 : 1990 (E)
20 Control object WE-parameters . 32
20.1 usage and effects of control object VTE-parameters . 32
20.2 Usage and effects of data element VTE-parameters . 34
m.3 Standard control objects . 35
21 Reference Information Object VTE-parameters . 40
21.1 Availability . 40
21.2 VTE-parametersfor RIOS . 40
22 Operations on Reference Information Objects . 40
22.1 Availability . 40
22.2 Identification of RIO and RIO records . 40
..................................
22.3 RIO update operations 40
................................
22.4 RIO reference operations 40
23 Device object WE-parameters . 41
23.1 Default control object VTE-parameters . 41
23.2 Minimum LengthVTE-parameters . 41
23.3 Device object WE-parameters for Attributes . 42
23.4 Termination VTE-parameters . 42
23.5 Interaction between use of TCCO or FDCO and
device object VTE-parameters . 43
24 Delivery control, synchronisation and net-effecting . 43
24.1 No delivery-control . 44
24.2 Simple delivery-control . 44
24.3 Quarantine delivery-control . 44
24.4 Implicit delivery . 44
24.5 Update queues and priority handling . 44
25 Communication Model . 47
26 vT Senrices . 47
27 vT senrice sequences . 48
27.1 Phas es . 48
27.2 Phase transitions . 49
27.3 Ownership of the WAVAR access-right
..................... 49
27.4 Availability and usage conditions of VT services . 49
27.5 Sewice collisions in A-mode . 50
28 Establishment facility . 51
28.1 VT-ASSOCIATE service . 51
29 Termination facility . 53
29.1 Sewices . 53
29.2 VT-RELEASE service . 53
29.3 VT-U-ABORTservice . 54
29.4 VT-P-ABORT service . 54
30 Negotiation facilities . 55
30.1 Switch Profile negotiation . 55
30.2 Multiple interaction negotiation . 55
30.3 Sequence control for multiple interaction negotiation . 58
31 Data Transfer facility . 59
31.1 VT-DATA service . 59
---------------------- Page: 4 ----------------------
IS0 9040 : 1990 (E)
32 Delivery Control facility . -60
321 VT-oELIVERservice. . -60
32.2 VT-ACK-RECEIPT service . 61
33 Access-right Management facility . 61
................................
33.1 VT-GIVE-TOKENS service 61
...........................
33.2 VT-REQUEST-TOKENS servicg 61
34 Destructive Break facility . -62
34.1 VT-BREAK service . -62
Default VTE-profiles . 63
Annex A
A.1 introduction to VTE-profile definitions . 63
A.2 Notation for definition of WE-profiles . 63
A.3 S-mode Default WE-profile. vt-b-spr-sd . -64
A.4 A-mode Default VTE-profile. vt-b-spr-ad . -64
Annex B Explanatory notes . 66
8.1 Types of VT communication supported . 66
8.2 Aid to understanding the role of display objects . -66
8.3 Relation of update-window to buffering . 66
8.4 Control object semantics . 66
8.5 Echoing . 66
8.6 Echocontrol . 66
8.7 Echo control algorithm . 67
8.8 Termination conditions . 67
B.9 Synchronisation of update delivery . 67
8.10 Multiple Interaction Negotiation . 68
8.11 Semantics of display objects . 68
8.12 Repertoires . 68
8.13 Use of IS0 6429 Additional Controls in repertoires . 68
8.14 Font Assignment VTE-parameters . 69
8.15 Net-effecting . -69
8.16 Interrupt facilities . -69
8.17 Emphasis attribute . 69
8.18 Supplementary explanatory material on field facilities . 71
8.19 Supplementary explanatory material on block facilities . 75
Annex c ASN.1 OBJECT IDENTIFIER values . 77
C.1 For identification of this International Standard . 77
C.2 For identification of attribute assignment types . 77
Annex D Size of urgent control objects . 78
V
---------------------- Page: 5 ----------------------
IS0 9040 : 1990 (E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for voting. Publication as an International Standard requires
approval by at least 75 % of the member bodies casting a vote.
International Standard IS0 9040 was prepared by Technical Committee ISO/TC 97, ln-
formation processing systems.
vi
---------------------- Page: 6 ----------------------
IS0 9040 : 1990 (E)
Introduction
This International Standard is one of a set of standards produced to facilitate the
interconnection of computer systems. It is related to other International Standards in
the set as defined in the Reference Model for Open Systems Interconnection (IS0
7498). The Reference Model subdivides the area of standardization into a series of
layers of specification, each of manageable size.
The purpose of this International Standard (IS0 9040) is to define the service provided
Basic Class Service.
In the Application Layer by the Virtual Terminal
The Virtual Terminai Basic Class Service is provided by the Virtual Terminai Basic
Class Protocol specified in IS0 9041 and making use of services available from the
Association Control Service Element (ACSE) in the Application Layer and the Pres-
entation Service.
a
vii
---------------------- Page: 7 ----------------------
IS0 9040 : 1990 (E)
INTERNATIONAL STANDARD
Information technology - Open Systems Interconnection -
Virtual Terminal Basic Class Service
ASN.1 Object Identifiers for the objects defined in this Interna-
1 Scope
tional Standard and for use in a register of Virtual terminal
objects.
This International Standard defines, in an abstract way, the
externally visible Basic Class Virtual Terminal Service within
This International Standard does not specify individual im-
the OS1 Application Layer in terms of
plementations or products, nor does it constrain the implemen-
a) a model defining the interaction between users of the
tation of entities and interfaces within a computer system.
service;
There is, therefore, no requirement for conformance to this
International Standard.
b) the primitive actions and events of the service;
c) the parameter data associated with each primitive action
This international Standard applies to interactive applications
and event;
requiring terminal oriented communication expressed in terms
of the transmission and manipulation of graphical images
d) the relationship beîween, and the valid sequences of,
having the following characteristics:
these actions and events.
e) the images are composed of character-box graphic ele-
Theservice defined in this International Standard is that which
ments organised into a one, two or three dimensional struc-
is provided by the OS1 Basic Class Virtual Terminal Protocol
ture;
(in conjunction with the Association Control Service Element
and the Presentation Service) and which may be used by any
9 attributes may be associated with any graphic element to
user including other Application Service Elements. The rela-
quaiiiy its mode of display.
tionship between the standards for Virtual Terminal Service,
Virtual Terminal Protocol, ACSE, Presentation Layer Service
Control information for the communication can be modelled
and the user of the Virtual Terminal Service is shown in
using virtual terminal control objects, and multiple devices can
figure 1,
be modelled using virtual terminai device objects linked to the
other virtual terminal objects.
This International Standard also defines two standard default
virtual terminal environment profiles and describes the form of
registered virtual terminal environment profiles and control
2 Normative references
objects. Virtual terminai environment profiles define sets of
virtual terminal environment parameters for use in the estab-
The following standards contain provisions which, through
lishment ofvirtual terminal associations and subsequent nego-
reference in this text, constitute provisions of this international
tiation. This International Standard also defines a structure of
Standard. At the time of publication, the editions indicated
were valid. Ali standards are subject to revision, and parties to
agreements based on this International Standard are encour-
VT-user Virtual Terminal Service
aged to investigate the possibility of applying the most recent
provides service
editions of the standards indicated below. Members of I EC and
Virtual Terminal
IS0 maintain registers of currently valid International Stand-
Protocol
ards.
based on service provided
by ACSE service
IS0 646:1983, Information processing - IS0 7-bit Coded
ACSE
Character Set for Information Interchange.
and Presentation Service
IS0 2022:1986, Information processing - IS0 7-bit and &bit
Presentation
Coded Character Sets - Code extension techniques.
Protocol
IS0 2375: 1 985, Data Processing - Procedure for registration
of escape sequences.
Figure 1 - Relationship of this International Standard
IS0 6429:1988, Information processing - Control functions for
to other OS1 Application Layer Standards
7-bit and 8-bit coded character sets.
---------------------- Page: 8 ----------------------
IS0 9040 : 1990 (E)
IS0 7498: 1 984, Information processing systems - Open Sys-
I) confirmed service;
tems Interconnection - Basic Reference Model.
m) non-confirmed service;
n) provider-initiated service.
ISO/rn 8509:1987, Information processing systems - Open
- Service conventions.
Systems Interconnection
3.2 Association Control Service Element
IS0 8649 1 988, Information processing systems - Open Sys-
definitions
tems Interconnection - Service definition for Association Con-
trol Service Elements.
This international Standard makes use of the following terms
defined in is0 8649:
IS0 8824: 1 987, Information processing systems - Open Sys-
tems Interconnection - Specification for Abstract Syntax No-
a) application association;
tation One (ASN. l).
b) application entity title;
IS0 8825: 1 987, Information processing systems - Open Sys- c) application control service element (ACSE).
tems Interconnection - specification of Basic Encoding Rules
for Abstract Syntax Notation One (ASN, 1).
3.3 Virtual Terminal Service definitions
IS0 9041 -1 :1990, Information technology - Open Systems
For the purpose of this international Standard, the foliowing
- Virtual Terminal Basic Class Protocol - Part
Interconnection
definitions apply:
1: Specification.
3.3.1 VT-user: A user of the Virtual Terminal Service.
IS0 9834-4 'I, Information Processing Systems - Open Sys-
tems Interconnection - Procedures for Specific OS1 Registra-
3.3.2 Application VT-user: The unique VT-user which can
tion Authorities - Pari 4: Register of WE-profiles
update the FDCO; if either VT-user can update this control
object then neither VT-user has this designation.
ISO 9834-5 '1, Information processing Systems - open sys-
tems Interconnection - Procedures for Specific OS1 Registra-
3.3.3 Terminai VT-user: If oneVT-user has the designation
tion Authorities - Part 5: Register of W Control Object Defini-
Application VT-userthen the peer VT-user has the designation
tions
Terminal VT-user.
The international Register of Coded Character Sets to be used
3.3.4 character-repertoire: A set of objects which can be
with Escape Sequences. 2,
represented by primary attribute values; one such object,
represented by its primary attributevalue, can occupy an array
element in a display object when the character-repertoire is in
3 Definitions
use for that array element. A control object of character-string
category also has an associated repertoire.
3.1 Global OS1 definitions
3.3.5 character-box graphic element: An atomic element
This international Standard is based on the concepts de-
of a character-repertoire where use of the repertoire has been
veloped in IS0 7498 and makes use of the following terms
agreed through negotiation by the VT-users.
defined In it:
a) application entity; 3.3.6 primary attribute: The attribute of an array element of 0
a display object which is a coded representation of the char-
b) Application Layer;
acter-box graphic element assigned to that array element.
c) service data unit;
d) service access point.
3.3.7 secondary attribute: The secondary attributes of an
array element comprise the character-repertoire, see 3.3.4,
It also makes use of the following terms defined In ISO/TR
and the rendition attributes.
8509:
3.3.8 rendition attributes: Those secondary attributes of an
e) service primitive;
array element which qualify the character-boxgraphic element
t) service provider;
and provide information specifying how it is intended to be
g) primitive;
presented.
h) request (primitive);
3.3.9 explicit modal default: The value for a secondary
i) indication (primitive);
attribute, defined in a WE, which is used by the text operation
j) response (primitive);
to update an array element if no other value is provided or
k) confirm (Primitive); already present; may also be used by the erase operation.
1) Tobepublished.
2) Available from the European Computer Manufacturers Association (ECMA), 114 rue du Rhône, CH-1204 ûenève,Switzerland.
2
---------------------- Page: 9 ----------------------
IS0 9040 : 1990 (E)
3.3.22 draft-VTE: TheVTE, if any, under negotiation. During
3.3.10 display object: An abstract object, defined in this
negotiation, the draft-WE is not necessarily a full-VTE.
International Standard, for modelling the exchange of graphic
information. It consists of a number of components, see 13.1.
3.3.23 VTE-parameter: An individual parameter of a WE.
3.3.1 1 array element: That part of adisplay object which can Each VTE-parameter is given a unique name in the service
which is used as the identifier for the VTE-parameter.
hold one character-box graphic element including its primary
and secondary attribute values.
3.3.24 full-VTE: A VTE that is a complete directed graph of
3.3.12 primitive display pointer: A set of one to three VTE-parameters in which all node parameters and terminal
leaf parameters implied by all existing nodes from the root of
coordinate values which identify a particular element in a
display object. the tree have values.
3.3.13 extended display pointer: A set of two to four coor-
3.3.25 VT-context-value: A collective term for the set of
dinate values which identify a particular array element in a object instances, their assigned values and the current-WE
block defined on a display object. for a particular VT-association. A VT-context-value exists only
during the lifetime of the VT-association and is normally
changing continuously during this time interval.
3.3.14 display pointer: Used to refer to either the primitive
display pointer or the extended display pointer; whether or not
blocks are in use determines which is implied.
3.3.26 reset-context: The VT-context-value which will re-
sult after a VT-BREAK service. This context value is the
0 3.3.15 logical pointer: A set of two or three coordinate context after the last successful current-WE establishment;
all objects will have their initial values. If no full-VTE has been
values which identify a particular array element In a field
established, there is no reset-context.
deflned on a display object.
NOTE -The primitive display pointer and extended display pointer do
3.3.27 WAVAR access-right: An access-right which can be
not both exist simultaneously. However, when a logical pointer exists,
held by at most one VT-user at any time. It is used to ensure
it is in addition to either a display pointer or an extended display
that control and display objects cannot be updated by both
pointer.
VT-users simultaneously.
3.3.16 control object: An abstract object, of a type defined
3.3.28 access-rule: A characteristic defined for an object in
in generic terms in this International Standard, for modelling
the exchange of unstructured information of a single type. aVTE which determineswhichVT-users can updatetheobject
at a particular time.
NOTE - The primary application of a control object is for modelling
the exchange of information of a control nature, as understood by the
3.3.29 net-effecting: The conversion of a sequence of
VT-users; the VT Service does not constrain the interpretation of this
items, representing the content of one or more update oper-
information.
ations (see 24.3), into a different, usually shorter sequence,
which results in the same final states of the objects being
3.3.17 device object: An abstract object used to model
updated.
certain logical characteristics of real devices, and to link the
various objects of a virtual terminal environment together
3.3.30 concatenatlon: The connection of a sequence of
and/or to real devices.
queued update items (see 24.3) to form asingle, new, queued
update item.
3.3.18 object updating device: A real device capable of
generating values which (possibly after undergoing a transfor-
mation) are used by one of the peer VT-users to update either 3.3.31 segmentation: The division of a single, queued up-
date item (see 24.3) into a sequence of new, queued update
a display object or control object (or possibly both).
Items.
3.3.1 9 VT-association: An application association between
two peer VT-users. 3.3.32 A-mode (Asynchronous mode): A mode of oper-
ation using two display objects, one of which is updatable by
the VT-user which initiated the VT-association and the other
3.3.20 VT-environment WE): A set of parameters that
by the peer VT-user.
together define the data structuring and operational charac-
teristics for a particular VT-association. The VTE exists only
during the lifetime of that VT-association. The parameters of 3.3.33 S-mode (Synchronous mode): A mode of operation
the set are mutually related by a directed graph structure. The using one two-way-alternate dialogue supporting one display
VTE may be modified during the existence of the VT-associ- object; at any time, the display object may only be updated by
ation by negotiation. the single W-user which owns the WAVAR access-right.
3.3.21 current-VTE: The single WE which exists during the
3.3.34 service: A distinct part of the total VT Service that is
Data Handling phase or the Negotiation Quiescent phase; in composed of a sequence of primitives taken from the set
the Data Handling phase it is a fuli-WE whereas in the
{request primitive, indication primitive, response primitive,
Negotiation Quiescent phase it is not a full-WE.
confirm primitive}.
3
---------------------- Page: 10 ----------------------
IS0 9040 : 1990 (E)
3.3.47 registered control object: A control object regls-
3.3.35 sequenced service: A Service for which an indica-
tered in a register of VT Objects administered by a Registration
tion (or confirm) primitive resulting from a corresponding re-
Authority established as defined in IS0 9834-5. It has as-
quest (or response) primitive is initiated in sequence with all
signed to it a unique ASN.1 OBJECT IDENTIFIER value.
previously initiated sequenced indications (or confirms) and
their corresponding requests (or responses),
3.3.48 privately defined WE-profile: A VTE-profile whose
3.3.36 non-sequenced service: A Service for which an use has been agreed privately by means outside the scope of
indication (or confirm) primitive resulting from a corresponding this Internationai Standard; it is neither a default VTE-profile
request (or response) primitive is not necessarily initiated in
nor a registered VTE-profile.
sequence with all previously initiated indications (or confirma-
tions) and their corresponding requests (or responses).
3.3.49 WE-proflle argument: An argument of a parame-
terised VTE-profile which must be given a value to enable a
3.3.37 conditionally sequenced service: A Service for
full-WE to be made from the WE-profile. It can be a normal
which
VTE-profile argument or a special VTE-profile argument. Each
registered WE-profile defines the applicable arguments and
a) certain values for parameters of the service primitives
their semantics.
result In sequenced operation, and
b) other valuesfor parameters of the service primltives resuit
3.3.50 normal WE-profile argument: A VTE-profile argu-
In non-sequenced operation.
ment which corresponds exactly to a WE-parameter and
assumes the same identifier. A VTE-profile may also speciiy
3.3.38 destructive service: A service that may cause the
that other VTE-parameters are also defined by the value of
0
loss of information conveyed in previously initiated services
such an argument.
loss to either VT-user. Only non-se-
without notification of this
quenced services may be destructive, but not all non-se-
3.3.51 special WE-profile argument: A WE-profile argu-
quenced services are destructive.
ment which does not correspond to a VTE-parameter (i.e., is
not from the directed graph and has no standard identifier) but
3.3.39 non-destructive service: A service that does not
has a valid use as defined in the VTE-profile definition.
cause the loss of information conveyed in previously initiated
services without notification to the W-users.
3.3.52 multiple interaction negotiation (MIN): A process
which enables a draft-WE to be modified or extended in
3.3.40 service parameter: A parameter defined as part of a
stages to create a new full-WE acceptable to the service
primitive within a VT service.
provider and both VT-users.
3.3.41 update-window: A mechanism associated with dis-
3.3.53 MIN-initiator: The VT-user that initiated the VT-
play object addressing which defines a range of coordinate
START-NEG service which was successful in causing the tran-
values for an array below which an update operation cannot
sition to Negotiation Active phase.
be performed. The absolute coordinate values in the range
may increase in value during operation, but cannot decrease.
3.3.54 MIN-acceptor: The VT-user that accepted the VT-
START-NEG service which was
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.