1. Get TK4- MVS Sofware
  2. Get wc3270 Terminal Emulator
  3. Install wc3270 Terminal Emulator
  4. Install and Run MVS 3.8j
  5. Logging In to/Out of MVS 3.8j
  6. Shutting down MVS 3.8j from TSO
  7. Using TSO RFE Application
  8. Adding a User
  9. Creating Datasets
  10. JCL Overview
  11. Your First Cobol Program
  12. Your First Assembler Program
  13. Your First Fortran Program
  14. Your First PL/1 Program

Your First Fortran Program

Fortran was one of the first compilers. It was created in 1957 by IBM and version have been made by virtually every operating system vendor. The first standardized version of Fortran was in 1966 and named FORTRAN IV. IBM created a couple of versions of Fortran IV named Fortran G and Fortran H. They were for machines with different memory. MVS 3.8J has both compilers. For many years fortran was heavily used in science, engineering, and math. It is no longer used as heavily as in the past.

Let's go over the Fortan code

A cobol line consists of three different sections. Positions 1 - 6 are for a line id. If position 7 is not blank, then the line is a continuation of the prior line. Positions 8 - 72 are for code.

        000001 110   FORMAT( ' NAME IS ' 20A1)    
        000002 120   FORMAT(20A1)                 
        000003       LOGICAL*1 NAME(20)           
        000004       READ(5,120) (NAME(I),I=1,20) 
        000005       WRITE(6,110) NAME            
        000006       STOP                         
        000007       END                          
Line #Description
1This line has an ID number allowing the line to be referenced in certain statements. The code portion is the Format statement which is defining a print line. The ' NAME IS ' is a constant and is followed by the 20A1 which means that it will display 20 alpanumeric 1 character fields.
2This line also had an id number and is a format statement defining a 20 alphanumeric fields that are 1 character long.
3This defines a LOGICAL field that is 1 character long and is an array of 20.
4This statement reads from device 5 using the format defined in id 120. It reads into the array NAME starting at index 1 and going through index 20. This is done this way so that it can read a 20 character name from the sysin (device 5) input. Fortran IV Compilers did not have good support for string fields and defining name as 20 1 charcter fields allows compiler to essentially fake a string.
5This statement writes on device 6 using the format from id 110 and outputs the name array. Device 6 is defined in the JCL that runs this code.
6Tells the program to stop execution.
7Indicates that this is the physical end of the program.
Embedded Source
JCL Job Stream with embedded source

            //FORT.SYSIN DD *                                                 
            110   FORMAT( ' NAME IS ' 20A1)                                   
            120   FORMAT(20A1)                                                
                  LOGICAL*1 NAME(20)                                          
                  READ(5,120) (NAME(I),I=1,20)                                
                  WRITE(6,110) NAME                                           
            //GO.FT06F001 DD SYSOUT=*,DCB=(RECFM=FBA,LRECL=132,BLKSIZE=13200) 
            //GO.SYSIN DD *                                                       
            GEORGE WASHINGTON                                                 

Notice the line GO.FT06F001, the 6 indicates that this is the DD line for device 6 in the program.

External Source
JCL Job Stream with external source

            //GO.FT06F001 DD SYSOUT=*,DCB=(RECFM=FBA,LRECL=132,BLKSIZE=13200)
            //GO.SYSIN DD *