Term3 for ZCPR3 pdf

Ó 0 i I I I l i t l I t I I l t I S I l I 0 Ó S t l Ó l I I t 4 b Ó S g l l g B 6 i t T 0 C Ó I t I I 6 C t t l l I I 0 I I I I t i l I i J t l I i t 0 I t l 2 t t I 2 I t I 0 I C d t i l Ó t I 4 Ó q f j i i ¢ t 0 I i t I t l } t l S l $ J I l } i } 0 i 0 l j $ j t t I 0 I 0 1 i I t I I Ú 0 I t I 0 I t l I f 6 Ú I t I t t l g F 0 t t t Q I d $ i l f k { 6 l i t t I 0 t t 0 i I S l I ¶ f S t I t I t d i I l t l g t l l Ó l 0 t Ó l l l l Ó t 0 I I b i t I I I b Ü I $ b t t i f I l l I t t t I I t I t t g I 4 t 0 l g l I l i I 0 q q I I l ¶ I g J g J I J g g b q I $ I q t Q E q I I l ¢ I l l t t i 0 I Ó ¶ t t I S I 4 g l E g I t I i I l I g I b f 0 l 0 I S t l i t 0 I $ i q Ó C t I I t t t l t t l t l ] J $ j S ! i g g t ¢ I t I E i L I 6 i 0 t 6 Ó 0 J O l g i l I I t 0 I 6 l Ó Ó b d I t J l g l á t 0 t t 0 I 6 I S C t 0 I [ ( i 6 Ó I 6 g I ( t t i t i C I j j t I P } l t l J g j S g t J t t 1 0 t Ó t l I 0 t S I Ó I I q t 0 I l q C I Ó I t I l L 0 Ó ¢ Ü Ó Ó 0 t I f b I 6 ! I I t t I I 3 I I I S i f I f I ( t l i l 0 B 0 I t I b t I I 0 ¢ t t I I Ó d 6 á I E 4 j I i t q I l I I l J ¢ I t I t i i t I l ( t 0 i Í I t I I I l 6 t t t ? i I t t Ó t t 6 i l i y j t j 4 ) 4 t g t I t 6 l l I t I I I t l I I y 0 I t I C I t l Y I t 1 t I I $ t i 4 k I 0 4 Q 6 f i Ó I t h Ó t Ó ¶ I t ( C Q i C r e k t g t t J l l i t t t t I t Ó I P l J j I I g i t 6 I I t g l I t I I t t g l 6 I Ó 6 Ó } I t t l J t t t t t 0 t t I B 0 6 l S I q I g E l t l t Ó I P 0 Ó t { I Ó C t t t I t t I l t f I t l 0 I t t I t E I I I t l 6 4 I I I I 0 I t i b I I l I g I B 9 I S I g 0 t I t I t B g b I 6 I t y 6 I I 6 I I I 6 i l l $ j b I b l l l J l i j t i t q t 0 S Ó I $ ¶ t q t i Ó ¶ 0 I 0 t 6 t O I l 0 I I I Ó I g b O Ó b I l I i l 0 I ¢ I Ó E [ I E S 6 t Ó t C f 4 C t t E l t 0 t l Ó l t b J t l I I J t 4 b f b g j t I t t Q D j C I U I Ó q I I I I I I I I I q t O 0 I I 6 O 6 Ó I O I q t I i I I t 6 0 t 0 U g l 0 Ó f

TERM

III

A _{Ccmnunications Sy8tem}

_for

the ZCPR3 U8er

Written

by

Richard Conn

Copyright 1985 _Richard Conn

t á k i b S l g I 6 i 0 I I f Ó I Ó I 0 Ó 6 I 6 b I Ó I l t f 4 i Ó ¶ I C I ( f q C d f g f I I C t t t I l t t 6 l t } Ó l f g 0 I I ! ! I g I $ I t I y b I I 0 I E t 0 B I I I t a ) q t I E l l t l t b I l $ 0 t t t g I t t 0 3 t 0 l I I Ó ( ( f g t $ t C d q t S I i I t l t t D t l g I ¶ t S i J b i D i I Ó S C l 0 B I } 0 i 0 S I t I t t l 6 I i I I Q Ó 6 f t 0 I g I $ I I Ó I t I g I t t t l i I I 4 I C I f 4 ( 3 i 1 S l t i t 0 t t b 6 l l 0 t Ó l B l l Ó l I 4 6 t 6 i 0 I t g t t l I l I t f Ó I I I t I t l I f I i t k I i 4 j l I l i l l l I g b I t 6 I g b l b l g g l g I i l 0 t 0 I I E t t f t I I l ¢ q I I 0 I S I I I Ó I t I 0 t t t ( g l t Ó t 8 t 0 I I 6 t Ó i t t q t O I C t i t t l l l t l t t Ó e i J g J ! i g B $ l J t t t q t I G l l g S g 6 i I i l 0 I 0 I t i b l 6 I S i t I t I 6 I t I 6 á I I I ¢ E i 6 I ( J t C t f C i ( t C I g l t I t t t t I I t I l 0 l j l I 0 l l t Q t I I t Ó l Ó l S D Ó l 4 4 4 t 0 I t 4 0 Ó 4 y L I t g Ó 0 I 0 I t I I I 0 I I I l I Ó I Ó I f I t f t I f f ) 0 t 0 I l I 0 I S I 6 $ I I l I ¶ I 6 I t I S I I I t 6 t I t I $ { 0 I 4 t 0 E 0 I 0 t 0 j 0 l 0 I i I S l Ó I ¢ Ó t C t t l t t t t t I t l } l t } G t J 1 J l b D S J B i 4 t t I I g I t I f I ! l t I G I t t I 6 t I G l 0 I I I t L j l 6 g t i k I I t I Ó l Ó I Q I 6 f I Í $ t Ó I i i d l I C I t t t t t t I t l } l $ J g J g l J l f i t I t I I t I I t t t l I 6 i Ó I I I 4 i i t l 4 I I j I 0 I 0 I q l á t I g 0 Í l I t 0 b t I É I 0 i f I f f f ( S I C I 6 t t t I l C I 4 I b S ¿ i t I E Ó i 6 ? i I i t 0 I t t Ü t 0 l S t I t S I $ I l I Ó f I 6 I I ¶ S t I S l I 0 ¶ S I t ¶ t I q I i J S l l Ó B l l t I j l I q t t I l L t D i t g t t Ó t t 0 t S q I I i t l q I O t t t ¢ E q I i t t t I I b { l I I $ C i V I C t t t I I t t l l t l P i l I l f i j I J E J t 9 6 Ó I I 0 I I j I Ó l f I I b I 0 I t l E Q b I S I S I t l 0 I g I 0 I Ó I t b i t t I t g i 6 t t I t t ( I C t J t t t I t t I t l l l l I g l t l I I ] l g 6 g I I l I t I Ó I I l I I I I Q l 4 L I I g I j f I g I t I 4 I t I k I t 6 t ! I t b 0 I f I S I 6 I ¢ l g I I 0 I 0 I C t t t ¢ i i Q t l 3 t b b I g 6 I t I Ó l i 6 I C 1 6 ] t l Ó d i t Ó i l I I l 0 I t j 6 I t i t t i ! Ó l t 6 I I I I l t I i I l I I t á ! I i I t b J b t ) J t t 0 t t i l [ S I 0 t I t I l I t t I Ó t t t l f t I 4 I I I I b I t I t f I I b l t I ( I 3 I ¢ Q t I t l C 6 0 € 8 C O i t l t t t t Q V l t t } l g l ! t Ó } l I l I j l Ó I t I I t 0 L f t Q t I 6 I t I i 4 4 Ó 0 I Ó I ¢ i $ b i I i i l b I b l b g Ó l 0 I 0 t l l I Q ( 0 q t f C ( I C t I i t i l l t i t l l l t l } I I I t l Q I C I k l 0 I Ó l g I 0 ¢ I t i S t l O 0 8 t t 8 t t 6 I l t I t i g l I l i I 4 l t I i 0 b I I Ó I S l 0 f f l t E Ó 6 g l l t I l S I t 6 I l t I i t Ü t t t l Ó l l 6 $

»

0 I t f $ I 6 $ I I 0 I S i i t I t I b t Ó I 0 I g l l I S l t i a } t l l 0 j t g i 0 8 $ l B t I J L Ó I I t g t i I I t k t t q t f t q C l l I t i g t g I t I I t f I l S l j I I t 0 I I l 4 Ó t t t f 6 ( 8 [ C l C S C t i t C i l d t l 6 0 l D l j I 9 I S I 0 b I l l l t I I l I I l Ó l I t I ,' l O $ Q I Ó l t l t I g S l t I Ó t 0 t I l C t Q I t i l 6

Document and program Copyright 1985 _{Riehard L.} Conn. No

_{part of}

this

document _{inay be reproduced}

_in

_{any manner}

_or

_{by any means}

without written

consent

of

the

_publisher.

Contact Echelon,

_Inc.,

P R E F A C E

This document describes the TERM

III

Communication System. The

operational

concept

_{is overviewed herein,}

and

_{the various}

commands _{are described}

_{in detail.}

The

_initial

_release

_of

_the TERM

III

System

_differs

from the

information

presented

_{in this}

document

_in

the

_following

_ways:

o the T3FILER program

is

not

yet

complete

-

the TERM

III

protocol is

not implemented

-

the KERMIT and CIS

protocols

are not

implemented

-

the Batch

transfer option

under MODEM7

is

not implemented

o the

following

_{programs are not provided} and the

information

presented _{on them}

_{is subject to}

change (moreso than the other cormands):

-

T31XJ

-

TM1ASTER

-

T3SERVER

o the

selection of

niodeins under T3SEI1MOD (the

file

T3MODCAP.MCP)

_is

_not

_yet

_complete

A _{second release (phase} 2)

_of

_the TERM

III

System

_is

planned

in

which these

_features

_will

be _{included. This}

_initial

_release

(phase

_{I) is presented}

due

_{to user desire,}

and Echelon

_will

distribute

the

second

_{release without}

_any

_additional

charge

_to

all

users who

placed

original

orders for the

TERM

III

System.

The

_{documentation}

_{on these}

_{features is subject to}

change

_since

design changes may be

later

made during

final

implementation and

testing.

Minor documentation changes and

_feature

changes may be made

_to

_the

_other

TERM

III

System commands _as

_well.

The

_creationof

theTERM

_III

System has taken _over a

_year,

and

_{this effort}

has been _on

_{the order of the creation}

_{of the}

ZCPR3 _System

_itself.

_Take

_{time to}

_{study thoroughly}

_this

_document

and the supplied examples before

_installing

the TERM

III

System

and adapting

_it

_to

_your

_{applications.}

Thank you

for

your

interest

and support.

Richard Conn

I t k I t I L k t f i i ! i I I i t k I \ I É I t i É ( t ( I q i l I S t I l I E i l I I i ( 1 l ( ¢ Í f ¢ ( ¢ ( t i I i l I I \ l I É f ( É I t ¢ É I f l t I t l $ I i L i F i É S J t I t i g I ¢ 6 t i l l i á t t I ) I l I S I i ( [ É ( f 5 l F i É I P l I t ¢ i l i l I l t I i F t $ i I ( I t l l l l I 4 I L f l t I á I I K i i S I \ I i I t i ¢ { t S t i P I I ? I i I i h I t É I I i l Ó I i i 0 ( I l $ É l I ¶ l i I ? ( t I } \ 1 I t t t t t 1 t I l I t t L l l g l t l l l } I I ) l ) I I ¶ I I j : t I I t t t I t f t I I ! t k l t I S f L I t t I É l l t t É l 1 t I l I t I I t 4 É ( t t l l l I I I ) I l j ) ) F i t i t $ l i I q I ¢ I i I I i I S l t f I t t I t l l I t I l I I i b l | l i t ( I t ) I t t l l t I i I i I ) J i j g I t I 1 I k ) I ¢ } i t l f t 4 I l l l l l i I I 1 K I I i t I t 1 I ) I l t I I t i l k t l l t t l ? b l ¶ $ I g b J i I f É ) I t I I I $ t I I I É t I t ) I k t É l I t I I i t I l I I l l t k l ) l I } É I t t k t t t t t 1 l t l i ) ) ) t l t I ( t 4 t I t I f I l l l t l I i I I i t É k l t i I t t I t 4 I b I L I l l l L t t ( i ( I l t t t } I ) $ I i j ! ) 4 i t ) ¢ P t t I ¢ i l l l I t \ t \ l t l É t I t t t t i I b I ¶ i I t I t k f Í I { l r q i t t t t l l t l t l l k l I ) l É I k t I l I t L k t i t t l i l } t É I J i ) l ) É i I ( i i I { t É I t C S i I i l I : f t t t l l } t i ) ) ! t I i ) I ¶ ) l t t i I | I t I l I L I i t t I L l t I i k 1 t I t t I b i t ) i j i i ¢ ¢ ( ¢ I q ¢ l t t l t t } } l l ) l I I l J É t I i S l I I l I I l I l I t I 4 K { f I I I l t l I i k t t } j t t ( f ( f q i ( f t i t t I l t } I t t I l l l ) f t l k i ( I I $ t L l | t I ( t f I l I i l I l I I t h t I i } É I I t f { 4 I É { É i E ( ¢ t t t t { t t t b l 1 1 E t j l ¢ l i l K É t f P i \ ( I t É I l t t I I t I i k \ $ k É 1 t l t I t I ! I t ( 1 I i t i i ¢ l l ( ¢ t l t l ) l ¢ I t L É ) b l i l $ I I k b b É L f i I l t I ) I t i l I

TERM

III

A _{Communications System}

_for

the ZCPR3 _User

Written

by

Richard Conn

Copyright 1985 _Richard Conn

I t t l l ( j t f t i L \ I I S i t i $ t I t f I I 1 I É i k ) t j g I ¥ I g i É ) t I l I t t t 4 I t t ¢ t l ! f i É l É t I I P I t á I t t i $ i I E | ¶ ) l 1 I I I l t t ¢ l l } J l l b l l ) l I g k I I i k t I l l t t I i h t I l i I l I ) i t ¢ É ¢ t { I l I t i ! t \ t I t t \ É 1 t I l 1 t i i t t l r l t l I l i P j } i t P I I I I Í i f t I t ¢ b I t I i I k f ) t l t I t l h t I l t h t l t t l l i É | t l t $ t t t i t } l t J } b i ) I I I I I I i I t ( t t É t i t t É I K I \ ¢ t I t t $ l ¢ $ l l i I t I t ¢ I i k I t t { C l l t t } t l l } i I $ t I l b I J l I I \ $ l i É $ I t g t i I t t i É k I I t ( \ I g I t k I I $ F t É i t I i t l t ( k t t t t l E l t t } g I t ) l E l t l i i j I l t t l l I t t I } I É I i i É 1 t Í i k l I L \ t Í t i 1 ¢ ¢ t t ¢ Ó i ¢ t t t l t C P I t I b l S l I ) I B l g t I

Marketed and

_Distributed

by: :

:::::::::::::::::::::::::::::

Echelon, Inc :

:::::::::::::::::::::::::::n

101

_{First Street}

:

:::::::::::::::::::::::::::::

Los

_Altos,

CA 94022 :

:::m::::::::::::::::::n:::

415/948-3820 :

:::::::::::::::::::::::::::::

k I t t É t I i I 1 I I t t I t t \ l I i t t i I t É l l I i { t 3 l ¢ I S { ( F i { ¢ t i | i j t i t t t E t i t l l

Z-Node

_Central:

:

::::::::::::::::)::::::::::::

415/489-9005 :

:::::::::::::::::::)::::::)::

T A B _L E O F C O N T E N T S

I.

The TERM

III

System...1-l

2. TERM

III

Basie

_{Coneepts...2-1}

2.1.

Use

_of

Menus vs Command

Lines...2-1

2.2. Applications

_{Environments...2-2}

2.3.

Remote Access Systems and

_ZCPR3...2-3

2.4. Input/Output

Packages _on a Remote Access

System..2-4

2.4.1.

"Normal" User

_{Environment...2-4}

2.4.2.

"Privileged"

User

_{Environment...2-6}

2.4.3.

SYSOP

_{Environment...2-6}

2.4.4.

Booting

_{Environment...2-6}

2.4.5.

User-to-üser

Environrnent...2-7

2.4.6.

Summary

_of

Console

_{Devices...2-7}

2.5.

Time Logging _on a Remote Access

System...2-8

2.6.

Comm

Sets...2-9

2.7. Result

_Codes...2-10

3. Command

Summary...3-1

3.1.

_{Communication...3-3}

3.1.1.

_{T3FILER...3-4}

3.1.2.

_{T3FLUSH...3-7}

3.1.3.

_{T3SEND...Á3-8}

3.1.4.

_{T3TERM...Á3-9}

3.1.5.

_{T3TERMB...3-10}

3.1.6.

_{T3TEST...3-11}

3.2.

Telephone

_{Controi...3-12}

3.2.1.

_{T3ANSWER"...3-12}

3.2.2.

T3DIAL* 0 0 * 0 0 0 * * 0 0 0 6 0 e 0 0 0 0 0 e e 0 0 0 e » 0 0 © e . » O

.3-13

3.2.3.

_{T3HANGUP*...3-14}

3.2.4.

_{T3INIT*...3-15}

3.3.

Access

_{Control...3-16}

3.3.1.

_{T3LOGCHG...3-16}

3.3.2.

_{T3LOGCK...3-17}

3.3.3.

_{T3LOGIN...3-18}

3.4.

Command

_File

Processing...3-23

3.4.1.

_T3DO...3-23

3.4.2.

_{T3MONRPT...3-27}

3.4.3.

_{T3VIEW...3-27}

3.5.

Communications

_{Server...3-29}

3.5.1.

_{T3MASTER...3-29}

3.5.2.

_{T3SERVER...3-32}

3.6.

_{Editors...3-33}

3.6.1.

_EDCST...3-33

3.6.2.

_EDTMC...3-35

3.6.3.

_EDTXD...3-35

3.6.4.

_EDXLT...3-36

3.7.

_{Miscellaneous...3-38}

3.7.1.

_{T3NOTE...3-38}

4. Examples

_of

Use

_{of the}

TERM

III

System...4-1

4.1.

_{Initia1ization...4-1}

4.2. Calling

a

_{Computer...4-1}

4.3.

Answering

_the

_{Te.lephone...4-3}

5.

_{Installation...5—1}

5.1.

_Installation

_{Instructions...5-1}

5.2.

_T3INS...5-2

5.2.1.

Key

_{Variables...5-3}

5.2.2.

Variables

that modify the

Corm

_Set...5-3

5.2.3.

Variables

_{for T3NOTE...5-4}

5.2.4.

Variables

_{for T3LOGIN...5-5}

5.3.

_{T3SELMOD...5-5}

5.4. Discussion of

Sample Modem

_{Overjay...5-6}

5.5. Discussion of

Sample Telephone

_Interface

_Overlay.5-8

APPENDICES

A.

_{References...A—1}

A.l.

ZCPR3 _and

Z-System...A-l

A.2.

_CP/M...A-2

A.3.

_Other...A-2

A.4.

Addresses

_of

Some

Publishers...A-2

B. Devíces Supported by T3MODCAP

I.I...B-1

B.1.

Ampro

_Little

_Bd...B-2

B.2.

_{Apple-Cat...B-2}

B.3.

Apple

_{Mountain...B-2}

B.4.

Big Board

_I...B-2

B.5.

CCS

2719...B-2

B.6. Datapoint

_1560...B-3

B.7.

Epson

_QX-1O...B-3

B.8.

Hayes

_MM1OO...B-3

B.9.

Heath

_H89...B-3

B.1O. Heath

_H1OO...B-3

B.1l.

Interfacer

_3/4...B-3

B.12.

_Kaypro...B-4

B.13.

_{MicroDecision,R1...B-4}

B.14.

_{MicroDecision,R2...B-4}

B.15.

_Phillips

_P200OC...B-4

B.l6.

SDS

Z80-SIO...B-4

B.17. Seattle

_{SCP400/0...B-4}

B.l8.

Seattle

_{SCP400/1...B-5}

B.19. Seattle

_{SCP400/2...B-5}

B.20. Seattle

_{SCP400/3...B-5}

B.21.

Super

_{Quad/Six...B-5}

B.22.

_{Superbrain...B-5}

B.23.

System Support

_1...B-5

B.24. Televideo

_TS-802...B-5

B.25.

TRS-80 Model

_I...B-5

B.26.

TRS-80 Model

_II...B-5

B.27.

TRS-80 Model

_III...B-5

B.28.

TRS-80 Model

_IV...B-5

B.29.

US

_Robotics

_S1OO...B-6

B.30.

_ZORBA...B-6

C.

_Listíngs

of

Sample

_{Overlays...C-l}

C.l.

Sample Modem

Overlay...C-l

C.2. Sample Telephone

_Interface

_{Overlay...C-4}

D.

_Distribution

_Files...D-l

I

N D E

X...Index-l

Introduction

TERM

III

I.

The TERM

III

System

TERM

III

is

a communications system which _runs under

the

Z-SYstem (the ZCPR3 command _processor

_{with, optionally,}

_the ZRIXJS

CP/M BDOS

_{replacement).}

TERM

III

consists

_{of over twenty}

programs which provide the

following capabilities:

o

interactive

communication

with

remotecomputer systsm o

reliable

file

transfer

between the user's computer and

remoteeomputers

o

control of

_an

auto-dial/auto-answer

modem

o _access

control for

remote system

_applications

(the user's

system can be set up

to

be

_{dialed into}

_{by outside users)}

o

rapid

and easy

reconfiguration of

the communications

environment

_{for different}

_applications

TERM

III

is integrated with

ZCPR3 _{and provides the Z-System}

user with

a communications

capability

that

_{can be adapted}

to

a

wide

_variety

_of

needs _{and can be used}

_{in conjunction}

_{with his}

other

Z-System

_tools.

The TERM

III

programs

return their result

codes (which

_indicate

the _{success or}

_failure

_{of their}

operation)

in

a _{manner which can} be examined using the IF command. TERM

III

programs can be employed

in

menus and

aliases

that

provide

commands and

_applications

environments which _are

_{tailored to}

a

user's

_specific

needs.

TERM

III

programs

rely

upon the environment provided by a

Z-System

_for

support. Some _aspects

_{of this}

_support

_include:

o

All

screen-oriented

displays obtain terminal-specific

information

from the ZCPR3 TCAP.

o Many

of

the _programs

_{return result}

codes (via the Program

Error

Message

_in

most cases) through the ZCPR3 _Environment

Descriptor.

o

File

references _can be

prefixed with

the ZCPR3

_directory

reference forms (DIR _or DU).

o Path searches _or

direct

ROOT _{accesses are employed as}

required.

o Messages and

_{other attributes}

_of

the ZCPR3 _environment

are used

extensively.

A

_large

_number

_{of features}

_were

_built

_{into the}

TERM

III

System

_inorder

_{to provide the user with}

_flexibility

_of

_{use and}

Introduction

TERM

III

use and

user-friendliness

are

also

key elements

of the design.

An

_{outline of}

_the

_{features of}

_the TERM

III

System

_follows:

1.

_Interactive

Comnunieations

o

terminal

rnode

_-

the user

"feels" like

he

is direct}y

connected

_to

the remote computer

_via

a

terminal

o conversation rnode

_-

the screen

is divided, with

incoming characters

_{printed in}

the top

_half

and

outgoing characters

_{printed in}

the bottom

_half

o

translation

tables -

all

incoming and outgoing

characters _{pass through}

_translation

_tables,

supporting

_parity

transmissions, masking

_of

selected characters _{(such as escape sequences),}

and using

_different

character sets _{(such as} EBCDIC)

o _macro

tables -

ten predefined

_strings

can be

transmitted at

_will

o

printer

output

_-

displayed characters _can be queued

to

the

_printer

o

buffer

load and dump

_-

displayed characters _can be

stored

_in

a rrternory

buffer

and dumped

_{to disk,}

printer,

or the remote computer

o XON/XOFF recording

_-

displayed characters _can be

stored

_in

a

disk

file,

using XON/XOFF handshaking

to

ensure no loss

of

data

o dynamic

setting

and

displaying of

environment

variables for

ease

of selection of features

2.

_File

Transfer

o several communications

protocols available,

including

XMODEM

_with

_Checksum, XMODEM

_{with crc,}

_and KERMIT

o batch

file

transfer

(sending

lists

of

files

using

wild

cards)

_{available with}

some

protocols

o comnunications server

_-

remote system access and

control

from the

_user's

system

_without

the need

for

the user

to

issue commands

_to

_{the remote}

system

_directly

3. Mod«n _Control

o _{answer the} telephone and drop

into

the Z-System

environment

_with

a

result

code (phone rang or

user

abort)

o

dial

the telephone based on mnemonics or

specific

telephone numbers

o

rotary dialing - dial

all

numbers

in

a

directory

file

in

sequence

until

one answers

o

multiple

telephone nuñber

directories

Introduction

TERM

III

4. Access Control

o UJGIN _program

o

selecting

the

attributes

of

a

user's

environment

based on the

user's

ID;

_attributes

_include:

-

command search path

-

ZCPR3 System Segments loaded

- startup

corrunand

line

-

various Environment

Descriptor

data

-

wheel byte and

quiet flag

o loading a TCAP

_entry

_{based on the}

_user's

_ID

5. Environment

_{Configuration}

o _use

of

Comm _{Sets (Ccmmunications Sets)} which

define

the aspects

_of

_{an environment} and can be

quickly

loaded as needed

o screen-oriented

editors to

create and

tailor

Corm _Sets

_easily

o automated _program

installation

procedure

with

installation

configuration

_files

The TERM

III

System was designed

to

meet the communications

needs

_of

the serious Z-System _user, and knowledge

_of

the Z-System

is required to

make

_effective

_use

_of

TERM

III.

The

_reader

_is

referred to

ZCPR3: The _Manual

_for

_a

_detailed

_discussion

_of

ZCPR3

and

_to

Echelon,

_Inc.,

and

_its

_newsletters

and

_{other supporting}

activities

for information

on the Z-System. See the References

appendix

_for

_more

_information.

This

document

_is

designed

_{to provide}

_{the reader with}

information

on how

the

programs

in the

TERM

III

System _are

intended

_to

be _{used under a Z-System.}

It

includes

_information

_on

the basic

concepts

_{of the}

TERM

III

System and how TERM

III

and

ZCPR3 _{can work}

_together.

_Details

_{on each program}

_in

_the TERM

III

System are presented,

including details

on

installation.

The

_information

_in

_this

document

_{is presented with the}

assumption that

the reader is currently

using

ZCPR3 _and

_is

familiar

with

many

of

its

fundamental

concepts.

The use

of

aliases,

menus,

flow control

commands

_(IF,

ELSE,

_FI),

_and

_the

command _{search path should} be _{understood by the reader.} See the

references

_for

help in finding

information

on

these

and

other

Concepts TERM

III

2. TERM

III

Ba8ic Concepts

This chapter discusses several concepts

_that

_are fundamental

_to

the design of the

TERM

III

System. The

_reader

must understand

these ideas

_in

order

_to

_use TERM

III

effectively.

In

surnmary, these concepts _are:

o Use

_of

Menus _vs Command _Lines o

Applications

Environments

o Remote Access Systems and ZCPR3

o Input/Output Packages on a Remote Access System

o Time Logging on a Rernote Access System

o Comm _Sets

o Result Codes

2.1. Use

_of

Menus _vs Command _Lines

Most

_{of the}

TERM

III

programs

provide the

user

with the

option of issuing

commands _{from a menu or}

_directly

_{from a command}

line.

The key

_functions

_{of these}

_{programs can be invoked} by

either

method, and the method employed

_generally

depends on the

user's application.

Command

_lines

_are

_useful

when _{menus or}

_aliases

_{are employed.}

For

_instance,

_the

TERM

III

System can be

set

up

to perform

operations

_{like this:}

Dial

the Telephone Number

_for

_System X

_(*)

If

answered

Log

_into

_it

_(*)

Send

_File

_FI

_to

_System X

(*)

If

transfer failed

Note

_failure

_{of transfer}

_(*)

end

_if

Test System X

_{for File}

F2

_(*)

If

File

F2

_available

Get

_File

F2 _{from System} X

{*)

else

Note lack

_{of File}

F2

_(*)

end

_if

Hangup _{the Telephone}

_(*)

else

Note

_failure

_(*)

end

_if

Each

_line

_of

pseudo-code

_listed

above corresponds

_to

_one

command

_to

ZCPR3. The _Z-System

_is

_{used as the executive}

_for

_the

processing of

_this

command stream. Those

_lines

marked

_with

_an

asterisk

(*) are performed by TERM

III

System commands.

This

command sequence

could

have been invoked by a _menu,

alias,

or command

file

(ZEX _or SUB) _{under the Z-System.} Command

_lines

_are

_also

_{handy when}

_the

user

is at

the ZCPR3

command

_level

_{and wants}

_to

_{issue a} command

_to

_{perform a}

_function

Concepts TERM

III

on the remote system

_{while staying at}

the command

_{level for his}

next

command. The

_fojjowing

_scenarios

_{illustrate this}

_(steps

done using TERM

III

System commands _{are marked}

_with

_an

_asterisk):

Scenario

_I:

User wants

_to

send

_file

_to

remote system

Send command

_{to display}

_dir

_{on remote system}

_(*)

Look

_{at results (*)}

Based on

results,

send command

_to

_{change name}

_(")

of

a

file

_{on the} remote system

if

it

duplicates

the name

of

the

file

_to

be sent

Send _the

_local

file

(*)

Scenario 2: User wants

_to

get a

file

from a remote system

Send command

_{to display}

_dir

_{on remote} szsystem

_(")

Look

_{at results (*)}

Look

_{for disk with}

enough room

for

file

Get the remote

_file

_to

the

_{target disk (*)}

2.2.

_Applications

EnvirOnments

The TERM

III

System was designed

with

three

applications in

mind:

o _{use as} a Remote _{Access System} (RAS)

-users

dial into this

system,

interact

with

_it,

and

_transfer

_prograns

_into

and

out

_of

_it

o _{use as} an

originating

Comrnuncations System

-the _user

_dials

out

_to

other computers and

corrununicates

_with

them, performing

_functions

which include

_file

_transfers

o _{use as} a

Configuration

System

-the _user configures the

_attributes

_of

the

other two types

_of

systems

Each

_{type of}

system

_{requires only}

_some

_{of the}

_files

_that

make up

the

TERM

III

System. The

_other

_files

_{can be}

_omitted,

resulting

in

a savings

in disk

_{space and} an increase

in security

(the _users

_of

the RAS _{cannot run programs}

_that

_can do _damage).

Some

_files

_associated

_with

these systems _are:

Remote _{Access Systems} (Z-NODES} T3ANSWER

- to

answer the telephone

T3HANGUP

- to

hang up the telephone

T3INIT

_{- (optional) to}

_init

the

_interfaces

T3LCGCHG

- to allow

a _user

_to

change

his

password

or

terminal definition

T3IAGIN

_{- to}

log _users

_in

T3NOTE

- to

log

activity

of

users

T3SERVER

- to

send and receive

files

Systems Used

_{to Call}

_Out

T3DIAL

_{- to dial}

the telephone, _{answer the}

phone, _{and hang up the phone}

Concepts TERM

III

T3TERM _or

- to

communicate

T3TERMB _{or T3FILER} T3MASTER

- to

communicate

(with

T3SERVER)

Systems Used

_{to Establish}

_Environments

T3INS

_{- to}

_install

Corm _Sets

_in

_programs

T3LCGCK

- to

check syntax

of

IÁX3IN.TXT

files

T3TEST

- to test

MODEM.BIN seginents

EDCST

-

Comn Set

editor

EDTMC

-

Macro Names

Editor

EDTXD

-

Telephone

Directory Editor

EDXLT

- Translation

Table

Editor

2.3.

Remote _{Access Systems and} ZCPR3

ZCPR3 _and

_the

TERM

III

System can

integrate

to create

a

secure Remote Access System (RAS). The

_{aspects of}

such _an

integration

which enhance

_its

_security

include:

o Path search _can

restrict

the commands accessed

by a _user

o

Disallowing

the DU _{form and}

_permitting

the _DIR

form

_{of directory}

reference only

_{automatically}

provides password

_protection

on

directories

o Many ZCPR3 _{cormands pay}

_{attention to}

_the Wheel

byte, and

_{privileged functions}

_{are disabled}

if

the Wheel _byte

_is

_turned

_off

ZCPR3 _{commands are}

_resolved

_by

_searching

_along a command

search

_path.

Only those COM

_files

_along

_{the path}

rnay be

executed. Hence, by

_carefully

_placing

harmless commands

_in

_the

directories

along

_{the path, the user is not granted}

_access

_to

commands _{which could do} damage.

ZCPR3

_{allows the}

_user

_to

_access

_directories

_by

_disk-user

references

_or

by name. The

disk-user

references

feature

_can be

disabled,

leaving only the

name.

This presents the

SYSOP

with

two major advantages:

o named

directories

_{can have passwords} associated

with

them, and these passwords must be _given

in

order

_to

complete the

_directory

reference

o only

directories

which _are named _can be accessed;

hence,

_if

a

directory

contains

files

but does

not have a name, the

files

in

it

cannot be

accessed

The PATH _and LDR _{commands are used}

_to

_change

_the

_{path and}

the

load

_different

named

_directories

_(or

_environment

descriptors).

Access

_to

these commands _{by a normal user has the}

EX)tential

_of

causing damage. _{Consequently, the} TERM

III

System

provides a _program

called

T3IÁGIN which performs these

functions

and more

without requiring

a PATH

_or

LDR command

to

be

available.

When _T3LOGIN

_executes,

_its

_{only inputs}

_from

_the

_{user are a}

user

name and password.

_It

searches

through

a LOGIN.TXT

file,

processing environment

_definition

commands _{and looking}

_for

_{a user}

name

_-

password match. When _{a match}

_is

_{found, the environment}

_is

configured

by T3LOGIN as

instructed

from

_the

LOGIN.TXT

_file.

Aspects

_{of the}

ZCPR3

_environment

_{which can be}

_configured

_by

T3LCGIN

_include:

Concepts TERM

III

o the cormand search path

o which system segments

_(including

named

_directory

files,

RCPs, FCPs, _{and lOPs) are loaded}

_in

the

_user's

environrnent

o whether DU _{forms are allowed}

o whether the Wheel byte

is

set

Consequently, the _{user can}

_freely

_{access and run} T3LCGIN

_at

both

_login

time _{and any time} during

_his

session. Who he _logs

_in

as determines the

attributes

of his

environment. The

other

ZCPR3

programs

(with

the exception

of

LDR, which

is

still

used

at cold

boot

_time)

used

_{to manipulate the user's environment}

_can be remved.

2.4. Input/Output Packages on a Remote _{Access System}

Input/Output

Packages (lOPs) _are segments

_{of the}

Z-System

which

_contain

_groups

_{of Input/Output}

_{device drivers}

_{for the}

Console, Reader, Punch, and

_{List logical}

devices. A _{Z-System may}

be _implemented

_{with or without}

_{lOPs. For a Remote AccesS System,}

lOPs

_provide

a

convenient

mechanism

to further

enhance

the

operation and

_{security of}

the system _as a whole.

Different

I/O environments _are required

_{for different}

types

of

communications

_{applications of}

a Z-System. Sorne

_of

_the eotnrrion

I/O

environments include:

o the environtnent

of

a "normal" _user

of

a RAS

c) the environment

of

_a

"privileged"

_user

of

_a RAS

o the environment

of

a SYSOP

calling

into his

RAS

o the

"booting"

environment when a RAS

_{is cold-booting}

o the

user-to-user

environment when a _person

is dialing

into

a Z-System

that is

attended by

its

_owner,

and the two people _{are going}

_to

work

_together

through the Z-System

2.4.1.

"Normal" User Environment

A "normal" _user

_is

_{one which} should not be _{allowed access}

_to

commands

_that

_can

_disrupt

_the

_{operation of}

_{the Z-System. These}

"dangerous" corrtrnands _may be

_physieally

_{removed from the} RAS, _but

certain

classes

_of

_users, such as a SYSOP who

is dialing into his

system

_{to perform}

maintenance, may need them. The Z-System

provides two convenient mechanisms which combine

_{to protect}

the

"dangerous" commands _{from execution by the "normal" user:}

o the comtnand search path

for

a "normal" _{user can} be set _up

in

such a way

that

it

does not include the

directory

containing

the "dangerous" commands

o the DU (Disk/User) form may be disabled, and the

"dangerous" comnands _may be _placed

_in

_a

_directory

_which

has a name and password associated

with

it

_or

_a

directory

which does not have a name

The TERM

III

program T3LOGIN has

the

ability

to configure

Concepts TERM

III

T3LOGIN

_accepts

_{as inputONLY}

_auser

name

andpassword,

and,

if

the pair is

_verified,

then _an

_environment

_{can be}

_established.

Passwords _can be

_omitted

_{from user names}

_in

_the LCGIN.TXT

_file,

permitting

T3LOGIN

_{to support}

commands

_like

"T3LOGIN

_INIT."

T3LCGIN _{can be viewed not only as a program}

_{to control}

_access

_to

the system, but also _as a general-purpose environment

controller,

where

_operational

environments _are

_{related to}

a

single

keyword.

It

may be

wise to employtwo copies of

T3LOGIN

for

this

typeof

application

so

that

users cannot

log in using user

names

like

INIT;

one T3LOGIN

controls

_access,

and a second

(under

a

different

name)

_controls

_{the environment}

_via

_keywords.

T3LOGIN has

_the

_ability

_to

_affect

_{the entire}

Z-System,

including

the

command search

_path

and

_the

named

_directory

segment. Consequently, T3LOGIN

_is

_{intended to}

_{be one}

_{of the}

first

programs run when a _user

dials into

a RAS and

it

should be

available

_publically

to

_all

_users.

T3LOGIN

_establishes

_the

user's environment, _{and the user can}

_later

change

_his

environment

(assuming

_that

_al!

_{of the}

"dangerous" commands _are

_properly

protected)

_only

by running T3IRGIN and

_providing

a

different

_user

name and password.

The _{communications environment}

_of

_{the "normal" user}

_of

_{a RAS}

is

one

in

which no

device selection

on

the part of the

user

is

allowed, the

_printer

_is

not

_available

(typing a ^P does nothing),

and

_{the console is timed}

and

_monitored

_for

_{loss of}

_carrier.

An

lOP _can accomodate

_this

by

_containing

a NULL

device

(which

performs a simple

return rather

than

outputting

a character) _as a

printer

and a console device

(call

it

REMOTE) which monitors the

user's

_carrier

_{detect line}

and monitors _{an elapsed} time counter.

The

_Input/Output

Package (lOP) _can

_contain

a

List

device

named NULL _{and a}

_{console device}

_named REMOTE, _{and T3LOGIN has}

_the

ability

to select

these devices by name.

The

_{console device}

REMOTE may be extended

to include

a

monitor

_{for activity}

from a CRT.

This monitor

would

look

for

a

special character to

come

in

from

the

CRT and

switch the

lOP

console to another device.

This other console device, called

REMOTEM _(forREMOTE

_Monitor),

_{ties this}

CRT

_{to the}

modem

_being

used by

_the

_caller.

_This

_tie-in

_{could take}

_avariety

_{of forms,}

with

two common forms being:

1. the CRT _and modem _{could share the}

_{I/O; le, input}

could come from

either

the CRT _{or the} modem,

and output would go

_to

both the CRT _and modem

in parallel

2. the CRT _{could dominate the}

_{I/O; le, input}

_could

come only from the CRT _{and output would go}

_to

both the CRT and modem

As _a

_further

_extension, REMOTE _{could look}

_for

_two

_different

inputs

from the CRT, _and

_select

REMOTEM1, _{which provides}

_for

_the

shared I/O

_of

the

_first

_{case (above), or} REMOTEM2, _{which provides}

for

the CRT-dominated í/O

_of

the _{second case.}

Concepts TERM

III

2.4.2. "Privileged"

User Environment

T3LOGIN

_is

_flexible

_{to the point of allowing}

_the

SYSOP

_to

define

a

different

environment for

EACH USER.

_{Consequently,}

there

can be as many classes of

privileged

_{users as desired,} each

class having

_{different capabilities}

and Z-System

_{environments.}

For example, one

class

can have command-search path A and

named-directory

set

_l

_while

another

_class

_{can have command-search} path

B _{and named-directory set} 2. The SYSOP

_himself

_{can have} a

third

comnand-search path and named-directory

_set.

The lOP can

further

support

_this

by

_{providing another type}

of

REMOTE

_{console device.}

_{This console}

_(call

it

REMOTENT

_for

Remote No _Timeout)

_is

_like

_the

_one

_before,

_{except that}

_the

elapsed time

_is

not monitored. Consequently, _{one or more classes}

of privileged

users can be

established

which have no

time

restriction

on the RAS.

2.4.3.

SYSOP _Environment

The SYSOP _can

_{enter the}

_{system as} a remote

_or

a

local user

(call

in or

direct line).

_It

is

a

logical

extension of the

concepts

presented

above

_{to allow}

_for

_one

_or

_more SYSOP

environments. As a minimum, the

local

SYSOP environment would

assign the console to

a

device (call

it

CRT) which does

not

monitor the

elapsed

_{time or}

_carrier

and have

_the

_ability

_to

reboot the system. Also, the remote SYSOP _{environment would use}

REMOTENT _as

_{the console}

_so

_{that time}

_limits

_{would not be a}

problem

_for

the SYSOP.

2.4.4.

Booting Environment

A _{good way}

_to

_ensure

_that

a Z-System environment

is properly

initialized

each

_time

a

_{user logs in is to}

have

the

Z-System

environment cold boot

when a

_user

hangs _{up on}

it.

This

_can

disrupt

a modem

in

the extreme, however,

if

all

of

the

text

which

is normally

sent during the cold boot

process

is sent to the

modem. For

_this

_reason,

_it

_is

recommended

_that

_{the output}

console driver

which

_is

employed

_{during cold boot}

be a NULL

console

_(like

the NULL

_printer).

No _output

_is

_sent

_to

_the modem.

The _{cold boot sequence could}

_{consist of}

_the

_following

_steps:

1. use BIOS _{console output}

_driver

_which

_{is null}

2. load system segments, and have the lOP come _up

with

a NULL _{console output}

_driver

3. set up environment

attributes

as desired and

change the path

_to

not include

_directories

which

contain "dangerous" cornmands (we _{are now}

_in

a "normal" _user mode); T3IRGIN could be used

to

do

_this

_{as an environment}

_controller

_(like

"T3IÁJGIN _INIT")

4. run T3ANSWER

_to

_{answer the phone; the console}

input driver

should

_allow

the

_local

CRT

_{to abort}

T3ANSWER _{so the} SYSOP _{can take}

_control

Concepts TERM

III

5. run T3LCGIN

_after

T3ANSWER _{terminates (even the}

SYSOP _should log

_in,

_or

_this

rriay be skipped

for

the SYSOP, _but the environment

_for

the

SYSOP may not be

properly established

if

T3IÁJGIN

is

skipped)

6.

_{exit to}

the Z-System from T3IEGIN or delay and

then reboot

_if

_{login failed}

(abort command

from T3LCGIN _could be _a

_delay/reboot

_sequence)

The _execution

_of

T3LQGIN

_in

_step 5

_{results in}

_{the complete}

establishment

of the user's environment

based on

_{his user}

name

and password.

2.4.5.

User-to-User Environment

A

user

may wish

to configure

his host

computer

to allow

another

person

to

call

in

and

interact

with

him

through the

one

system. An lOP _{console device}

_{for this}

scenario would be

_similar

to

REMOTEMI _{(both consoles share}

_equally)

_or REMOTEM2 _{(the user's}

console only provides input

and

_{both consoles}

view

_{the output)}

except that the modemcarrier wouldbe monitored

and

_{output to}

and

_{input from the}

modem _{would be suspended}

if

the

_carrier

was

dropped. This prevents problems

_with

modem

_interaction

_{on loss}

of carrier

from

_occurring.

2.4.6.

Summary

_of

_{Console Devices}

The lOP _{provides a}

_flexibility

_{not found under conventional}

implementations

of device I/O in the

BIOS.

_{While designing}

ZCPR3,

I

found the need

_for

the lOP

_to

be _{pronounced. Relying on}

the BIOS

_for

_all

_{the device I/O support was too}

_restrictive:

l.

the BIOS _had

_to

fit

on the system

tracks,

_so

it

was

tight

on space

2. the BIOS _{had no hooks}

_to

_provide

_for

_{rnore than}

_four

console,

_four

reader,

_four

punch, and

_four

_list

devices

By

_{implementing the}

_lOP

_{concept, several}

_{advantages were}

realized:

1. a

buffer of

IK or 2k outside the BIOS _{which contained}

all

of

the

_I/O

device

_drivers

would _{remove these}

drivers

(or

_all

but the simplest

_of

them) from the

BIOS, thereby

_shrinking

the BIOS, and simultaneously

provide _{more space}

_in

which

_to

implement _{more complex}

device

_drivers

2. the I/O Byte

_of

CP/M _{need no longer} be _{employed; the} lOP

jump

_table

_can be _a

_{mirror of}

_the BIOS _jump

_{table with}

extensions

_to

provide

_for

other mechanisms

_{to select}

the devices _{(such as by} NAME

_rather

_than

_bit-field

_in

a byte)

3. more than

four physical

device

_drivers

_{can be assigned}

to

each

_logical

device

Concepts TERM

III

The lOP

_{conceptcanbeextendedand}

employed

_ina

Z-System

which

_supports

TERM

III.

As

_outlined

_in

_this

_section,

_the

_lOP

for

such a system _{can support} devices _{such as the}

_following:

NULL

_printer

REMOTE _console

o monitors the

carrier detect line

and reboots

or

otherwise

restart8

the system

if

the

carrier

is lost

o monitors an elapsed time counter and reboots

or otherwise

restarts

the system

if

the

time elapses

o monitors the CRT

_{line for}

_{one or more} command

characters, and invokes _one

_or

_more

_other

devices based on these corrurands

REMOTEM1 _con3ole

o ínonitors the

carrier detect line like

REMOTE

c) _{may or may not monitor} elapsed time

o

input

comes from the CRT and modem

in

parallel

and goes

to

the CRT _and modem

in parallel

REMOTEM2 _console

o

like

REMOTEMI, but

input

comes only from the CRT

REMOTEM3 _console

o

like

RE6KYI'EM1, but

if

carrier

drops,

input

i

from and output

_to

the modem

is

s:unply

ignored

_(only

the CRT

_{is active}

when

the modem

_carrier

_drops) REMOTENT _console

o

like

REMOTE, but does not monitor elapsed

tine

CRT _console

o no

monitoring;

CRT

_input

_{and output only}

This

_list

is

by no means

complete, but

_it

should _serve

_to

give the reader

some

initial

ideas on what

types of device

drivers

he _would

_{like to}

_{set up}

_{in his}

_lOP.

2.5. Time Logging on a Remote Access System

The TERM

III

System programs serve

to

replace BYE, a p©ptüar

program used

to

run Remote Access Systems,

in

its entirety.

Almost.

The one

aspect of

bye which has

_not

been addressed

directly

by TERM

III

SYstem _programs

_{is that}

_{of user time}

logging.

_It

_{is frequently desirable to track}

the amount

_of

tirrte.

a _user spends on a system and

to kick

him

off

after

_{an hour.}

Concepts TERM

III

At user

login, start

the

_timer

and reset

_it

_to

zero

Throughout the session,

_periodically

check the

timer

If

the _user logs

_{out, turn off}

the

_tinier

If

the

_{timer expires,}

break the connection,

optionally

pause

for

a period

of tine, turn

off

the

_timer

The

_timer,

_then,

must be

_polled

_throughout

the user's

session,

and

_this

_{is best}

_{done by some aspect}

_{of the resident}

system _or an executive (such as BYE). This segment

of

the system

should

check

_{the timer at quiescent}

moments, such as

during

a

wait for

output.

The

_solution

_proposed

_{in this}

_document

_for

_the

implementation

_of

the

_{timer is}

_as a

part of

an

I/O

Package. This

I/O

Package (lOP) would

_provide

a

device driver

which _{uses the}

Modem _{as a}

_console

_and

_{monitors the timer.}

_The REMOTE

_device

discussed above

_is

_{one such implementation,} but

_there

_are other

possibilities.

The

_{console record function}

_(or

_printer

_record

function,

_for

that matter) of the

lOP can be used

to turn the

timer

on and

off.

Hence, when a _user

logs in,

a

part of the

user's default

command

_line

would be

_{to turn}

_on

_{the timer}

("RECORD CONSOLE ON" _{command) and}

_{to select the correct}

MODEM

device ("DEV CONSOLE TMODEM" command, _where TMODEM

_is

_the Modem

with

a

timer controlled

by RECORD CONSOLE

_directives).

_{For the}

sake

_{of security,}

T3L'CGIN _{can perform the same}

_functions

_{as the} DEV _and RECORD commands.

2.6. Comm _Sets

All

programs

in

the TERM

III

System which communicate

with

a

remote computer _use Comm _{Sets. At}

_installation

_time,

each

program

is

loaded

with

a Comm _Set

_(the

_built-in

Comm _Set)

_that

tells

_it

what to

do when

it

is

invoked.

The

_options

_at

invocation

are:

1. load the Corm _Set named _{on the} comnand

_line

2. load a Comm _{Set from}

_disk

3. use the

_built-in

Corm _Set

Al!

programs used

for

communication,

such as T3FILER and

T3TERM,

_contain

_a Comm _Set

_within

_{themselves (the}

_built-in

Comm

Set).

Upon

_execution,

these _programs examine

_certain

_{flags in}

this

Comm _{Set, and may}

_perform

_one

_{of the following}

_three

Comm

Set

_{selection functions:}

1. load a Corm _Set

_specified

_{on the} conunand

_line

2.

_if

no Corm _Set

_{is specified}

_{on the} command

_line,

load a Corm _Set

_{specified in}

_the

_built-in

Comm

Set

_if

the IIDAD

_(Initial

Load)

_{flag is}

set

_in

the

_built-in

Corm _Set

.

3. j-f no Comm _Set l-S spec1f/ed _{on the} command

_líne,

use the

built-in

Comm _Set

if

the ILOAD

_flag

is

not set

At

_this

point,

the

Comm _{Set which}

_{is present within}

_the

communication _program

_is

the Comm _{Set used}

_for

_{the session. This}

Comm _Set

_{is called}

_the

_default

Comm _Set.