Re: [open-cobol-list] What do you think of JCL ?

[Kevin Monceaux]

On Thu, Sep 19, 2013 at 12:24:54PM -0400, Patrick wrote:
 
> Would a Guile, Tcl, lua Open Cobol binding solve problems on the 
> mainframes normally tackled by JCL and provide an alternative to JCL?

JCL is **Job** Control Language.  With IBM mainframe operating systems if
one is going to submit a batch job, one pretty much has to use JCL.  The JCL
is submitted before the programs in the job execute.  For example, if I had
a HELLO program that read a message from a sequential file and displayed
hello + the message, the JCL to execute such a program in z/OS might be
something like(best viewed with a monospaced font):

    //HELLO    JOB ,CLASS=A,          ...HELLO WORLD JOB CARD
    //            MSGCLASS=X,MSGLEVEL=(1,1)
    //**********************************************************************
    //HELLO    EXEC PGM=HELLO         ...HELLO WORLD STEP CARD
    //MESSAGE  DD  DSN=DO.KPM.B.S.MESSAGE,DISP=SHR
    //**********************************************************************

The JCL was indented to make it stand out from the rest of this message.
The // characters have to start in column 1 on the mainframe.  I would
submit the job using the above JCL with the TSO SUBMIT command.  The JCL
would execute the HELLO program and the program would access the message
file as MESSAGE without needing to know the full dataset name.

I could use a shell script to achieve similar results on Linux:

    #!/bin/zsh

    export DD_MESSAGE=/path/to/message.txt

    /path/to/hello

Like the JCL on the mainfrmae the above script on Linux would execute the
hello program and the program would be able to access the message file as
MESSAGE without knowing the full path or file name.




-- 

Kevin
http://www.RawFedDogs.net
http://Lassie.RawFedDogs.net
http://www.WacoAgilityGroup.org
Bruceville, TX

What's the definition of a legacy system? One that works!
Errare humanum est, ignoscere caninum.