Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!cornell!rochester!kodak!ektools!kadsma!brunjes
From: brunjes@kadsma.kadsm (Roy Brunjes)
Newsgroups: comp.lang.misc
Subject: Re: CICS what is it?
Message-ID: <184@kadsma.kadsm>
Date: 27 Sep 88 16:56:45 GMT
References: <3923@okstate.UUCP> <8943@srcsip.UUCP> <5740@utah-cs.UUCP> <2081@cuuxb.ATT.COM>
Reply-To: brunjes@kadsma.UUCP (Roy Brunjes)
Organization: Eastman Kodak, Rochester NY
Lines: 72

In article <2081@cuuxb.ATT.COM> kjc@cuuxb.UUCP (Kevin Coulter) writes:
>In article <5740@utah-cs.UUCP> u-dmfloy%sunset.utah.edu.UUCP@utah-cs.UUCP (Daniel M Floyd) writes:
>>CICS.
>>
>>Since I don't know what it is, I don't know where to post;
>>however, I think it's some sort of language.
>
>CICS (what the acronym stands for - hmm - maybe Customer Interactive Computer
>System?) What it basically is is an operating system that allows on line 
>transactions. It was developed by IBM for their machines. As far as I know, the
>only two languages you can use with it are COBOL & assembler. Since COBOL is
>not my favorite language, but is the recommended language for it, I agree with
>your guess:
>>Maybe Crumbly Icky Computer System. :-))
>
>			Kevin

CICS stands for "Customer Information Control System".  It is not an operating
system perse, rather it runs on top of an operating system (MVS) on an
IBM 370 architecture machine.  It does to its own "internal" multitasking, and
thus is sometimes mistaken for an operating system.

It's main function in life is to process transactions, which are tied to
application programs via a set of tables (CICS tables that are actually
files maintained by system programmers).  The user talks to CICS usually
through a 3278-type terminal which has the usual drawbacks for the ability
to supply an acceptable user interface.

CICS can utilize DL1 (Data Language 1) to talk to an IMS database.  I haven't
been in that world for three years now and so I don't know if it can talk
to DB2 (but I would assume IBM would want this since DB2 is a strategic
product of theirs).

IBM calls CICS a "telecommunications monitor" or "telecommunications
monitoring subsystem" or words like that.  Having been both a VTAM systems
programmer (VTAM being IBM's contribution to telecommunications on mainframes)
and a CICS systems programmer, I fail to see anything related to telecomm.
in CICS.  Oh sure, it can be accessed via a network, but so can anything
else!

From a programming language interface point of view, I know that COBOL and
Assembler interfaces are provided, and I believe PL/1 and FORTRAN (I'm really
stretching my faulty memory here) are also provided.  COBOL is by far the
most commonly used language with CICS.

A big drawback of CICS 1.6.1 at least (the last release I worked with -- I
now work on Suns and VAXen [Suns preferred]) is that all applications live
in the same chunk of memory (address space to use the MVS term).  Thus, if
you and I both write applications, and my application has an array index that
gets set to some wild value, I may write data all over your executable code,
thereby causing your program to crash (almost assuredly) with an S0C1 (invalid
instruction exception).  Nasty.  Your code may be just fine.  YOU must read
the transaction dump to see why your program crashed.  You must then determine
who's program plunked some string into the middle of your code!  Nasty.

Better yet, my junky program might write on CICS code!  Yeah!  Now the whole
"region" (as it is usually called) goes down the tubes.  Several hundred
users can be blown out of the water when this happens [actual numbers depend
naturally enough on the number of users on when this happened].  Nasty.

You get the feeling I don't like CICS?  No kidding!  It is stone-age stuff.
Just like the terminals it runs on.  Living dinosaurs.  But, you can make
around $40K these days being one who babysits CICS while it runs (a systems
programmer) or even more being one who writes clunky applications to run on
CICS!  So, given that approx. 70% of all IBM mainframe shops run CICS, there
is some job security (for the near term at least, if not more).

Sorry to ramble so much.  I don't often get the chance to spout off about
how much I think CICS stinks.

Roy Brunjes   ...rochester!kodak!kadsma!brunjes
Disclaimer:   These opinions are my own, not those of my employer.