F o u r s p e c i a l - p u r p o s e s t a t e m e n t s a r e s u p p l i e d t o d o c u m e n t , s i m p l i f y, a n d s e p a r a t e n e t w o r k d e fi n i t i o n s :
TITLE statement A n N D L i n p u t fi l e c a n c o n s i s t o f s e v e r a l n e t w o r k
a n d l o c a l d i v i s i o n s ; t h e s e d i v i s i o n s c a n a p p e a r i n a n y o r d e r w i t h i n t h e n e t w o r k d e fi n i t i o n . N D L P c r e a t e s o n e n e t w o r k c o n fi g u r a t i o n fi l e f o r e a c h n e t w o r k d i v i s i o n i t e n c o u n t e r s w h i l e p r o c e s s i n g y o u r p r o g r a m . N D L P a l s o c r e a t e s o n e l o c a l c o n fi g u r a t i o n fi l e f o r e a c h l o c a l d i v i s i o n i n y o u r program.
COMMENT statement DEFINE statement END statement
The DEFINE and COMMENT statements are not shown in fi g u r e 2 - 4 b e c a u s e t h e y n e e d n o t a p p e a r i n a p a r t i c u l a r o r d e r o r w i t h i n a p a r t i c u l a r d i v i s i o n . STATEMENT HIERARCHY
The relationship between network elements is defined by the placement of the statements used to define them. For example, a COUPLER statement that follows an NPU statement defines a coupler that is connected t o t h a t N P U . F u r t h e r, a L O G L I N K s t a t e m e n t t h a t f o l l o w s t h e C O U P L E R s t a t e m e n t d e fi n e s a l o g i c a l l i n k t h a t o r i g i n a t e s i n t h a t c o u p l e r.
S t a t e m e n t s m u s t o c c u r w i t h i n t h e p r o p e r d i v i s i o n a n d , e x c e p t f o r t h e f o l l o w i n g s t a t e m e n t s , m u s t occur in the order shown in figure 2-4:
APPL COMMENT DEFINE INCALL
OUTCALL T I T L E TRUNK USER / ^ S \
/jjpB&v
60480000 M
TITLE STATEMENT
A TITLE statement allows you to title each page of y o u r o u t p u t l i s t i n g . T h e f o r m a t o f t h e T I T L E
statement is shown in figure 2-5.
T h e r e c a n b e o n l y o n e T I T L E s t a t e m e n t i n e a c h p r o g r a m d i v i s i o n . Yo u c a n p l a c e T I T L E s t a t e m e n t s a n y w h e r e w i t h i n N D L p r o g r a m d i v i s i o n s a f t e r t h e NFILE or LFILE statements.
U s e o f t h e T I T L E s t a t e m e n t i s o p t i o n a l . I f y o u d o not use the TITLE statement, the file name specified o n t h e N F I L E o r L F I L E s t a t e m e n t i s u s e d a s t h e title of the NCF or LCF. A TITLE statement without a c h a r a c t e r s t r i n g p r o d u c e s a n u n t i t l e d l i s t i n g . Character strings must not exceed 45 characters.
2-5
Network Division NFILE statement
CTITLE statement]
TRUNK statement
-*-Repeat for each new n e t w o r k c o n fi g u r a t i o n
fi l e r e q u i r e d .
Repeat for each line linking two NPUs.
NPU statement SUPLINK statement
COUPLER statement
LOGLINK statement
1-Repeat for each super v i s o r y l o g i c a l l i n k . Repeat for each coupler.
Repeat for each logical s
-•Repeat for each NPU.
J l i n k s t a r t i n g i n t h i !c o u p l e r.
LINE statement [GROUP statement:
TERMINAL statement DEVICE statement-LTERMDEV statement!
Repeat for each terminal connected to this line.
Repeat for each device connected to this terminal, Repeat for each terminal
connected to this line.
Repeat for each line.
NPU statement
Local Division
LFILE statement -*- Repeat for each new
l o c a l c o n fi g u r a t i o n fi l e r e q u i r e d . CTITLE statement]
CUSER statement:
CAPPL statement:
COUTCALL statement:
CINCALL statement:
Repeat for each terminal that requires an auto m a t i c o r d e f a u l t l o g i n .
Repeat for each application program with special access requirements in the host.
Repeat for each path that can be used for requests for connection to another application program.
Repeat for each application program that can accept requests for connection from another application program.
END statement Only one per NDL
program.
Figure 2-4. NDL Program Statement Hierarchy
2-6 60480000 L
TITLECstring:.
string Character string up to 45 characters long; includes any blanks following a comma separator. The string can contain any characters in the 6 - b i t display code set except for a period;
a period terminates the title d e fi n i -tion. The default string i s 45 blanks.
Figure 2-5. TITLE Statement Format An example of a valid TITLE statement is
TITLE, SUNNYVALE CLOSED SHOP MHR NCF.
In this example, the listings and the network configuration file produced by the NDL program would contain the title line shown, identifying the CDC Sunnyvale facility environment NCF used by the CDC CYBER 170 closed-shop multiple-host network.
COMMENT STATEMENT
A COMMENT statement permits you to insert text comments into NDL input. The NDL processor copies these comments, without editing or interpretation, into the output listing of your NDL source state ments. The format of the COMMENT statement is
shown in figure 2-6.
JCOMMENTl r . . , r ,
^ j Z , s t r i n g : C . :
string Character string up to 89 characters long (asterisk form) or up to 82 characters long (COMMENT form). The string can contain any characters in the 6-bit display code set. A
comment string terminates at the end of a line, regardless of whether or
not there is a terminating period.
There is no default for string.
Comments that appear after the terminating period of a statement must be in the form:
♦string
Figure 2-6. COMMENT Statement Format Use of the COMMENT statement is optional. COMMENT statements can be placed anywhere within NDL pro gram divisions.
An example of a valid COMMENT statement is COMMENT THIS IS A VALID COMMENT STATEMENT
set of declarations is then stored as a character string for insertion in subsequent parts of the NDL program; the string is inserted by placing the identifier in statements where the stored declara tion set is needed.
Use of the DEFINE statement is optional. The format of the DEFINE statement is shown in figure 2-7.
defname: DEFINECstring.il
defname The identifier assigned to the character string. This is a name of one to seven Letters or digits, the first of which must be a letter. The identifier should not be an NDL reserved word (see appendix D) and cannot be an NDL statement name or keyword. This name is required;
there is no default value.
st ri n g T h e c h a r a ct e r str i n g fo r w h i c h the defname identifier is substituted when writing other NDL statements. This character string must contain complete value declarations and can contain commas, equals signs, blanks, and any letters or digits; it cannot contain a period, because a period is interpreted as the end of the DEFINE statement. The string can contain NDL reserved words but cannot contain NDL statement names or another DEFINE name.
Figure 2-7. DEFINE Statement Format
A DEFINE statement must precede any other statement that uses the identifier specified in the DEFINE statement. The defname identifier can only be used in an NDL statement where the NDL processor expects to find a keyword.
DEFINE statements can be placed anywhere within NDL program divisions after the NFILE or LFILE state ments. DEFINE statements apply only to the division in which they occur.
Nested DEFINE statements are not permitted. The identifier of one DEFINE statement cannot be used in the character string that defines the declaration set of the same or another DEFINE statement. The character string of a DEFINE statement cannot contain another DEFINE statement.
As an example of this statement's function, consider the following portion of an NDL program:
LTYPE3: DEFINE LTYPE=A1,TIPTYPE=ASYNC.
PORTA: DEFINE PORT=l.
DEFINE STATEMENT
A DEFINE statement allows you to assign a label (identifier) to a set of keyword and value declara tions that is cumbersome to anter repeatedly. The
LINE5: LINE PORTA, LTYPE3.
The first DEFINE statement permits the identifier LTYPE3 to be substituted in subsequent NDL state ments (such as the last statement in this example)
60480000 M 2-7
f o r t h e c h a r a c t e r s t r i n g LT Y P E » A 1 , T I P T Y P E » A S Y N C . L I N E A : D E F I N E L I N E . P 0 R T- 1 . N o t e t h a t t h e L I N E s t a t e m e n t i s s t i l l t e r m i n a t e d b y LT Y P E 3 : D E F I N E LT Y P E = A 2 . a period because this character string is considered
to end with the C, not with the period that termi nates the DEFINE statement.
LINE5: LINEA,LTYPE3,TIPTYPE-ASYNC.
The second DEFINE statement equates the identifier PORTA to the character string PORT-1, so that the
L I N E s t a t e m e n t i s a c t u a l l y i n t e r p r e t e d b y t h e N D L E N D S TAT E M E N T processor as if it had been written
An END statement must explicitly terminate the last L I N E 5 : L I N E P O R T = l , LT Y P E = A l , T I P T Y P E - A S Y N C . d i v i s i o n i n t h e N D L p r o g r a m . T h e N D L p r o c e s s o r r e q u i r e s t h i s s t a t e m e n t t o d e t e r m i n e t h a t t h e i n p u t D E F I N E s t a t e m e n t s r e c e i v e s e p a r a t e d i a g n o s t i c fi l e i s c o m p l e t e ,
treatment when the NDL program is processed. How
ever, if a DEFINE statement contains an NDL coding This statement has the format shown in figure 2-8.
e r r o r i n i t s c h a r a c t e r s t r i n g , t h e e r r o r m i g h t n o t be diagnosed until an attempt is made to expand the d e f n a m e i d e n t i fi e r *
T h e f o l l o w i n g c o m b i n a t i o n o f s t a t e m e n t s w o u l d n o t be recognized as expanding into a valid NDL state
m e n t , b e c a u s e t h e r e s e r v e d s t a t e m e n t n a m e L I N E c a n - F i g u r e 2 - 8 . E N D S t a t e m e n t F o r m a t not be found in the unexpended version of LINE5:
^ ^ § v
<^®§\
2 - 8 6 0 4 8 0 0 0 0 M