3100, 3200, 3300 Fortran; Generalized Sort/Merge Program - Control Data 3100 Reference Manual

The COBOL compiler is a three pass system. No objectcode is produced until the entire source
program has been thoroughly analyzed. Whenever possible, in-line coding is produced.
Depending on the needs of the program, the compiler provides an input/output system which
allows variable length
records~
up to two buffer areas per file, multi-file reels, multi-reel files,
and so forth. In general, the features of the COBOL input/output system correspond
to
those
described for the Data Processing Package.
3100, 3200, 3300 FORTRAN
The 3100,3200,3300 FORTRAN system incorporates a problem-oriented language that
facilitates simple algebraic solution of mathematical or scientific problems.
3100,3200,3300 FORTRAN programs are written as a sequence of statements, using
familiar arithmetic operations and English expressions. Large programs may be written
independently in sections, the sections tested, then executed together.
Statements are available to reserve areas of memory for variables and arrays. Strings of
values may be loaded with the program for reference during the program execution.
Equivalence statements allow the same areas of memory to be identified with different
variables and arrays during the execution of a program.
Type statements specify the mode in which values are to be stored. The possible types
include: REAL, INTEGER, and CHARACTER. The programmer may also declare a
special mode, type OTHER, to handle information which does not conveniently con-
form to the standard modes.
Arithmetic expressions are indicated by arithmetic sign and algebraic names. For ex-
ample, A+B- C means add A to B and subtract C. Logical and relational operators are
available for use in expressions which may be true or false.
Statements are usually executed in sequence. However, control statements may be
used to transfer to another part of the program. (The transfer may be specified as de-
pendent on a test indicated by an expression in the transfer statement.)
Sets of statements which are to be executed several times with minor changes or incre-
ments may be written once with a statement to indicate how many times they are to be
repeated, and if they are to be changed each time.
Input/output operations provide a means to read information into the machine from
various sources and to record results on a selected output device. If buffered input/out-
put operation is specified, other operations may continue while information is read in
or out.
Facilities are also available to transfer a number of characters from one area of memory
to another, and to test machine conditions through calls to 3100, 3200, 3300 FORTRAN
library functions.
The 3100,3200,3300 FORTRAN compiler produces machine language programs which
may be executed immediately or stored for execution at a later date.
GENERALIZED SORT/MERGE PROGRAM
The GENERALIZED SORT/MERGE PROGRAM organizes data on magnetic tape
into one continuous predetermined order. SORT/MERGE operates under the SCOPE
operating system. Control cards read from the standard input unit contain file descrip-
tions and SORT/MERGE specifications.
8-5
Rev. B