o Sequential input and output files o A S C I I o r E B C D I C r e c o r d f o r m a t s o Fixed or variable length records o Blocked or unblocked records
o L a b e l t y p e in f o r m a t i o n s p e c i f i e d o n t h e O C L F I L E statement
F O R T R A N I V
, M a g n e t i c t a p e f i l e s c a n b e c r e a t e d a n d r e a d u s i n g t h e I B M l S y s t e m / 3 F O R T R A N lV . Y o u c a n s p e c i f y a d e v i c e ( u n i t ) ' n u m b e r
a n d th e b l o c k s i z e f o r e a c h t a p e fi l e a t c o m p i l e t i m e . A t e x e c u t i o n t i m e , th e F I L E s t a t e m e n t s a r e u s e d t o a l l o c a t e u p t o f o u r t a p e u n i t s f o r t h e F O R T R A N p r o g r a m . T h e c o m p i l e r a n d li b r a r y r e q u i r e a m i n i m u m m a i n s t o r a g e size of 9K bytes exclusive of system control program re-q u i r e r n e n t s . T h e F O R T R A N lV c o m p i l e r c a n b e e x e c u t e d o n a m i n i m u m c o n f i g u r a t i o n s y s t e m . F o r o b j e c t p r o g r a m s s u p p o r t i n g m a g n e t i c t a p e o n t h e M o d e l 1 0 D i s k S y s t e m , a p r o c e s s i n g u n i t w i t h a t l e a s t 1 6 K b y t e s o f m a i n s t o r a g e i s r e q u i r e d .
Logical records can span two or more single record blocks.
The logical record size of unformatted records depends solely on machine capacity allowing tape work f iles to be used advantageously when handling large arrays.
S y s t e m / 3 F O R T R A N lV s u p p o r t s :
o Formatted, list directed, and unformatted tape input and output
o Fixed lengith, unblocked records with record lengths of from 18 to32,767 characters (bytes) read or written under control of a FORMAT statement
o Variable length, unformatted records with a block size of from 18 to 32.767 bytes
o R E A D ( w i t h o p t i o n a l e n d - f i l e , E N D , a n d e r r o r p r o c e s s i n g , E R R , p a r a m e t e r s ) , W R I T E , E N D F I L E , B A C K S P A C E . a n d R E W I N D s t a t e m e n t s
M A G N E T I C C H A R A C T E R R E A D E R U T I L I T Y P R O G R A M
T h e 1 2 5 5 M a g n e t i c C h a r a c t e r R e a d e r U t i l i t y s u p p o r t s t h e t a p e u n i t a s a n o u t p u t d e v i c e f o r c r e a t i n g s i n g l e v o l u m e f i l e s ' T h i s u t i l i t y p r o g r a m c a n b e e x e c u t e d o n a m i n i m u m c o n -figuration system with the exception of a Model 'l
0 Disk S y s t e m f o r w h i c h a m i n i m u m o f 1 6 K b y t e s o f m a i n s t o r a g e i s r e q u i r e d . N o c h a n g e i n c o d i n g i s r e q u i r e d i n t h e 1 2 5 5 u t i l i t y p r o g r a m s p e c i f i c a t i o n s t o s u p p o r t t a p e o u t p u t r a t h e r t h a n d i s k o u t p u t .
T A P E S O R T P R O G R A M
The Magnetic Tape Sort programs use the tape drives as w o r k f i l e s to s o r t a t a p e f i l e in t o e i t h e r a s c e n d i n g o r d e s c e n d
-ing sequence. RPG I l-type statements are used to specify record selection, sort parameters, and data f ields. The sort s o e c i f i c a t i o n s s t a t e m e n t s a r e s i m i l a r i n f u n c t i o n a n d a r r a n g e -ment to the tag-along sort function of the disk sort pro-g r a m . T h e s u m m a r y s o r t fu n c t i o n i s n o t s u p p o r t e d .
System Requirements
The magnetic tape sort programs operate with the minimum I System/3 conf igurations.
Tape Sort Files
The Tape Sort program requires three types of files: input.
output, and work.
lnput and OutPut Files
Tape input and output files can be recorded in either E B C D I C o r A S C I I c o d e s . R e c o r d s i n t h e s e f i l e s m u s t b e fixed length but can be either blocked or unblocked'
E B C D I C f i l e s a r e s o r t e d d i r e c t l y ; n o t r a n s l a t i o n i s n e c e s s a r y ' A S C I I fi l e s c a n b e la b e l e d o r u n l a b e l e d . A N S I la b e l s a r e used for labeled ASCII files. Labeled files must be trans-lated to EBCDIC before processing. After all processing i s f i n i s h e d , t h e f i l e c a n b e tr a n s l a t e d b a c k t o A S C I I a n d written on the output file.
Magnetic Tape Program Product Support 19
U n l a b e l e d A S C I I f i l e s c a n b e s o r t e d d i r e c t l y , using the A S C I I c o l l a t i n g s e q u e n c e . O n l y c h a r a c t e r compansons are v a l i d ; s p e c i f i e d s o r t c o n s t a n t s a r e t r e a t e d a s E B C D I C d a t a . T h e s o r t e d r e c o r d s a r e w r i t t e n i n A S C I I c o d e o n the output f i l e . Y o u m u s t n o t s p e c i f y tr a n s l a t i o n of output files for u n t r a n s l a t e d A S C I I f i i e s .
Work Files
T h e t a p e s o r t p r o g r a m r e q u i r e s a t l e a s t th r e e w o r k f i l e s ; a f o u r t h w o r k f i l e i s o p t i o n a i . Work files can share tape units w i t h t h e i n p u t a n d o u t p u t f i l e s .
/ y ' o t e . ' W h e n u r ; i n g S E O N U M - x a s a w o r k F I L E s t a t e m e n t p a r a m e t e r f o r r n u l t i f i l e v o l u m e s , y o u m u s t b e s u r e that the t a p e i s p o s i t i o n e d p a s t th e l a s t file on the volume that vou w a n t t o p r e s e r \ / e ( M o d e l 1 5 o n l v ) .
Sort Functions
T h e T a p e S o r t p r o g r a m c r e a t e s a s o r t e d fi l e o f a l l r e c o r d s s e l e c t e d . O n l y t h o s e fi e l d s y o u r e q u e s t from the lnput records are included in the sorted records. Output recorcls a r e s e q u e n c e d b y t h e d e s i g n a t e d c o n t r o l f i e l d s fr o m t h e c o r r e s p o n d i n g i n p u t r e c o r d s . F i e l d s id e n t i f i e d as data fields a r e i n c l u d e d in t h e o u t p u t r e c o r d s , b u t h a v e n o e f f e c t o n the sequence o{ the records. After records are sorted, the s o r t c o n t r o l f i e l d s c a n b e d r o p p e d fr o m the output records.
Record Selection
R e c o r d s t o b e s o r t e d a r e s e l e c t e d f r o m t h e i n p u t f i l e b v t h e t a p e s o r t p r o g r a m a c c o r d i n g t o y o u r s p e c i f i c a t i o n s . y o u c a n s p e c i f y th a t r e c o r d s b e s e l e c t e d o n t h e b a s i s o f a c o m -p a r i s o n o f t w o f i e l d s w i t h i n t h e r e c o r d , o r t h a t selection b e b a s e d o n a c o m p a r i s o n o f a f i e l d w i t h i n t h e r e c o r d a n d a c o n s t a n t . Y o u c a n a l s o s p e c i f y m u l t i p l e tests sucn as c o m b i n a t i o n s o f f i e l d - t o - f i e l d a n d f i e l d - t o _ c o n s t a n t c o m p a r i -sons. These comparisons direct the sort program ro accept a l l o r o n l y p a r t i c u l a r re c o r d s fr o m t h e i n p u t file.
Field Selection
You must specify the fields on the input record that are c o n t r o l f i e l d s a n d / o r d a t a f i e l d s . F i g u r e 8 s h o w s an exampte o f f i e l d s e l e c t i o n . F i e l d s s p e c i f i e d a s c o n t r o l f i e l d s a r e u s e d by the sort program to determine the order of the records i n t h e o u t p u t f i l e . M u l t i p l e c o n t r o l f i e l d s up to a combined length of 256 bytes can be specified. Ascending or descend_
i n g s e q u e n c e c a n b e s p e c i f i e d f o r e a c h fi e l d . y o u m u s t specify which data fields from the input records are to be i n c l u d e d in t h e o u t p u t r e c o r d s ; a l l o t h e r f i e l d s a r e d r o p p e d when the output record is created.
I n t h e o u t p u t r e c o r d , a l l c o n t r o l f i e l d s from the rnput r e c o r d a r e p l a c e d a h e a d o f a l l d a t a f i e l d s ( i f the key is not dropped), but you can choose the order of the control and data f ields in the output record. Fields specif ied as control f i e l d s c a n a l s o b e d u p l i c a t e d a s d a t a f i e l d s within the data portion of the output record.
Multiple record types with different formats can be sorted i n e a c h s o r t r u n . F o r e x a m p l e , y o u c o u l d sort debit and c r e d i t r e c o r d s a t t h e s a m e ti m e .
Additional Features
The tape sort program provides a checkpoint option that allows you to restart processing from a point other than the b e g i n n i n g i f a s y s t e m fa i l u r e o c c u r s . W h e n a checkpoint is taken, the program records enough information for a restart t o b e m a d e f r o m t h a t c h e c k p o i n t . SEONUM x may not be
u s e d a s a w o r k F I L E s t a t e m e n t p a r a m e t e r w h e n c h e c k p o i n t restart has been specified on the header statemenr.
The tape sort program also provides diagnostic messages.
T h e s e m e s s a g e s d e s c r i b e e r r o r s a n d u n u s u a l c o n d i t i o n s in the sort control statements.
Audit controls in the tape sort program keep record counts.
The number of input records. records selected for sorting, and output records is recorded by the audit control feature to ensure that no records are lost in the sort process. Se-q u e n c e c h e c k i n g is a l s o p e r f o r m e d on the sort output file to ensure that the output records are in the proper order.
20
C o n t r o l F i e l d s D el r m i n e s th e o r d e r o f t r d s i n t h e o u t p u t f i l e r e c c
F 1 F 2 F 3 F 4 F 5 F 6 F 7 F 8 F 9 F 1 0 F i 1 F 1 2
il
D a t a F i e l d s T o b e i n c l u d e d in t h e
t h e
I N P U T
output record
O U T P U T R E C O R D
F i e l d s F 1 0 , F 1 1 , a n d F 1 2 a r e d r o p p e d f r o m o u t p u t reco ro.
c o n t r o l a n d d a t a f i e l d
Note: The keys or control fields were not droppeo.
S o r t C o n t r o l F i e l d
F 2 F 9 F 7 F 3 F 6 I F 4 F 5 F 1 F 7 F 8
F i e l d 7 ls designated as both a
F i g u r e 8 . C o m p a r i s o n of Input and Output Sort Records
lvlagnetic Tape Program Product Support 21
Page of GC21'5040-3 l s s u e d 3 0 J u n e 1 9 7 8 B v T N L : G N 2 1 - 5 6 0 4
B A S I C A S S E M B L E R There are two rules:
B y u s i n g th e B a s i c A s s e m b l e r , y o u c a n w r i t e a s s e m b l e r . T h e s p e c i f i e d r e c o r d l e n g t h ( i n t h e R E C L p a r a m e t € ' r )
language programs that support magnetic tape. Magnetic must be at least 4 bytes larger than the largest record'
tape is not used for program assembly.
o T h e s p e c i f i e d b l o c k l e n g t h ( i n t h e B L K L p a r a m e t e r ' ) m u s t
System macro instructions are available with the SCP to be at least 4 bytes larger than the specified record iength'
simplify coding required by the assembler. Macros perform
t h e f o l l o w i n g f u n c t i o n s fo r t a p e : A h a l t i s i s s u e d i f e i t h e r o f t h e a b o v e is v i o l a t e d .
o B u i l d a p r e o p e n D T F f o r t a p e a n d a s s i g n i t s o f f s e t s . F o r m a x i m u m e f f i c i e n c y . h o w e v e r , t h e f o l l o w i n g a l g o r i t h m i s r e c o m m e n d e d :
o Build the interfaces required to read input records from
a t a p e d e v i c e v i a a G E T o r R E A D . B L K L = N ( R + 4 ) + 4 p E 6 1 = R + 4 o Build the interfaces required to write output records to
a t a p e d e v i c e v i a a p U T o r w R l T E . w h e r e R i s t h e s i z e o f t h e l a r g e s t r e c o r d a n d N i s t h e r n i n i -m u -m n u -m b e r o f r e c o r d s d e s i r e d in a b l o c k '
o Build the interface required to issue tape control
c o m m a n d s . F o r e x a m p l e . t o c r e a t e a v a r i a b l e r e c o r d le n g t h ta p e v / i t h the largest record 60 bytes and at least two records p')r o W a i t f o r c o m p l e t i o n o f r e a d . w r i t e , o r t a p e c o n t r o l b l o c k , s p e c i f y B L K L - 1 3 2 a n d R E C L - 6 4 .
ooerations.
Note: Every block would contain at least two records with I S e e th e m a c r o s re f e r e n c e m a n u a l s li s t e d in t h e P r e f a c e f o r t h e p o s s i b l e e x c e p t i o n o f t h e l a s t b l o c k .
I m o r e i n f o r m a t i o n c o n c e r n i n g m a c r o i n s t r u c t i o n s .
T h e r e i s a n a d d i t i o n a | c o n s i d e r a t i o n w h e n r u n n i n g a r r a r i a b | e r e c o r d le n g t h ta p e j o b w i t h R P G l l . F i r s t . d e t e r m i n e B L K L
D l s K s o R T P R O G R A M a n d R E C L f o r t h e F I L E s t a t e m e n t u s i n g th e r u l e s s t a t e d a b o v e . T h e b l o c k l e n g t h i n t h e R P G l l f i l e s p e c i f i c a t o n s T h e D i s k S o r t p r o g r a m s a r e u s e d to s o r t a t a p e f i l e i n t o e i t h e r ( c o l u m n s 2 0 - 2 3 ) m u s t m a t c h B L K L , b u t t h e r e c o r d le n g t h a s c e n d i n g o r d e s c e n d i n g s e q u e n c e u s i n g d i s k d r i v e s fo r w o r k i n R P G l l f i l e s p e c i f i c a t i o n ( c o l u m n s 2 4 - 2 7 ] , m u s t b e R E C L - 4 ' f i l e s . T h e o u t p u t c a n b e o n e i t h e r a t a p e f i l e o r a d i s k f i l e . F a i l u r e to m a t c h e i t h e r o f t h e s e c a u s e s a h a l t .
Disk sort f unctions are similar to those for the Tape Sort
p r o g r a m e x c e p t t h a t t h e s u m m a r y s o r t f u n c t i o n i s a v a i l - F o r e x a m p l e , if t h e F I L E s t a t e m e n t h a s B L K L - 1 3 2 a n d a b l e i n d i s k s o r t , a n d d i s k s o r t d o e s n o t p r o v i d e a c h e c k - R E C L - 6 4 , th e n 1 3 2 m u s t a p p e a r a s th e b l o c k l e n g t h a n d 6 0 p o i n t o p t i o n . a s t h e r e c o r d l e n g t h i n t h e R P G l l F i l e D e s c r i p t i o n
S P e c i f i c a t i o n .
Special Considerationsfor Variable Length Records When tape containing variable length records is read, the
block length and record length specified on the Fl Lt: state-W h e n r u n n i n g a t a p e j o b w i t h v a r i a b l e l e n g t h r e c o r d s , t h e r e m e n t n e e d n o t m a t c h t h e o n e s o n t h e F I L E s t a t e m e n t w h e n
are conventions that must be followed concerning the BLKL the tape was created as long as:
( b l o c k l e n g t h ) a n d t h e R E C L ( r e c o r d le n g t h ) p a t r m e t e r s in
t h e O C L F I L E s t a t e m e n t . o T h e y o b e y t h e r u l e s a b o v e .
o B L K L i s a t l e a s t a s l a r g e a s t h e l a r g e s t b l o c k a n d I l E C L at least as large as the largest record on the tape'
22
M A G N E T I C T A P E S U P P O R T S U M M A R Y
Page of GC21-5040-3 lssued 30 June 1978 B y T N L : c N 2 1 - 5 6 0 4
The following chart describes the column headings and the appl icable program numbers:
T h e f o l l o w i n g c h a r t s h o w s th e t h r e e m o d e l s o f t h e t a p e s u b
Single Density Tape Unit Feature
This feature is installed on tape units to enable g_track, pE (phase-encoded) operations. Single density control is s t a n d a r d o n t h e 3 4 1 l.
Dual Density Tape Unit Feature
This feature is installed on tape units to enable 9-track oper-a t i o n s i n b o t h 1 6 0 0 bpi pE mode and g00 bpi NRZI (non-return-to-zero) mode. lf any tape unit is equipped with the d u a l d e n s i t y f e a t u r e , t h e 3 4 1 1 m u s t also be equipped w i t h the dual density control feature.
Seven-Track Tape Unit Feature
This feature can be installed on the tape unit portion of the 3 4 1 1 o r o n a n y 3 4 1 0 . lt enables t h e t a p e u n i t t o read a n d w r i t e d a t a in N R Z I mode on 7-track m a g n e t i c t a p e . R e a d i n g and writing are done at densities of 200, 556, or g00 bpi.
Odd or even parity is provided.
l f t h e 7 - t r a c k t a p e u n i t f e a t u r e i s in s t a l l e d i n t h e 3 4 1 1 o r a n y a t t a c h e d 3 4 1 0 , th e 3 4 1 1 m u s t aso be equipped w i t h a 7-track tape control feature. A 3410 or 341 t tape unit equipped with the 7-track tape unit feature cannot be equip-p e d w i t h either a single d e n s i t y t a p e u n i t f e a t u r e o r a d u a l density tape unit feature.
Dual Density Control Feature This feature. available for the 341 1 tape units to read and write 9-track b p i N R Z I o r 1 6 0 0 b p i P E mode.
c o n t r o l u n i t , e n a b l e s t h e t a p e in e i t h e r t h e 8 0 0
Seven-Track Control Feature
T h i s f e a t u r e , a v a i l a b l e f o r t h e 3 4 1 1 c o n t r o l u n i t , e n a b l e s t h e 3 4 1 1 t o c o n t r o l a n y t a p e u n i t ( i n c l u d i n g the tape unit por_
t i o n o f t h e 3 4 1 1 ) t h a t i s e q u i p p e d w i t h the 7-track tape unit feature.
A translator and data converter are included with the 7_track control feature. The translator, when set on, translates g-bit bytes from main storage to 6-g-bit BCD tape characters and vice versa. Each main storage byte becomes a taoe character; each tape character becomes one byte in main storage. The data rate is not changed by the translator.
T h e d a t a c o n v e r t e r a l l o w s w r i t i n g and reading of binary data on 7-track tape units. Writing a tape when the data converter is on causes four tape characters (24 bits) to be written for every three storage bytes (24 bits). Reading such a tape reverses the process by converting four tape characters into three storage bytes. Data conversion reduces the data transfer rate by 25 percent of that for 9_track N R Z I o p e r a t i o n s . A n o d d / e v e n count is made during read/
write data converter operations to ensure correct transfer of oata.
26