Re: [Fwd: Re: Mainframe not a good architecture for interactive was Re: What is the future of COBOL? Answer: Irrelevant???]]

From: Joe Zitzelberger (joe_zitzelberger_at_nospam.com)
Date: 01/27/04 

Date: Mon, 26 Jan 2004 22:27:15 -0500

I just had to drop in a few comments. Please forgive the middle-posting:

In article <bv1r7c$pgt$1@news.eusc.inter.net>,
 "Clark F. Morris, Jr." <cfmtech@istar.ca> wrote:
> I belated posted Pete Dashwood's comments to the mainframe list ibm-main
> and almost instantly got the following response. John does not follow
> comp.lang.cobol.
>
> -------- Original Message --------
> Subject: Re: [Fwd: Re: Mainframe not a good architecture for interactive
> was Re: What is the future of COBOL? Answer: Irrelevant???]
> Date: Sun, 25 Jan 2004 04:58:39 GMT
> From: John S. Giltner, Jr. <giltjr@earthlink.net>
> Organization: EarthLink Inc. -- http://www.EarthLink.net
> Newsgroups: bit.listserv.ibm-main
> References: <3FE0AC45.3070208@istar.ca>

Because of excessiive posting and reposting, I'm not sure if C.F.Morris
or J.S.Giltner posted this...but I have to comment.

>[much snippage]
>
> Hum, I bet Pete was an application programmer and not a system
> programmer. CICS only maintains the state of terminal that are in
> session with it, just like any and all "distributed" server
> applications. In the early days CICS did need to have pre-defined
> tables entries for any terminal that was going to connect to it, but you
> have been able to dynamically defined and delete this entries for over
> 20 years now. If distrubuted servers share the same single buffer for
> all connections/sessions how does it keep track if information that is
> unqiue to each connection/session.

The conceit of this statement is amazing. Do you realize that all of
the helpful applications that you, as a sysprog, use every day are
written by applications programmers???

There were days when sysprogs were selected from the ranks of
applications programmers for their willingness to understand the lower
level operations of things. That was something like 30 years ago.

Today, there is a pretty clear difference between "programmer" and
"administrator".

>From previous discussions on C.L.C. I know Peter Dw is quite clueless in
the areas of modern CICS. But I also have seen enough snippets of his
code to know that he is one of the few Cobol programmers that groks
sensible code construction, and is all around quite functional.

> > PC networks don't work that way. The devices on the network are
> > recognised by addressable hardware cards. There are a number of
> > protocols (not least of which is the ubiquitous TCP/IP protocol that
> > makes it possible for us to have this conversation) that simply transmit
> > packets around the network. Network servers pass messages to each other
> > until the required client is located. There is no requirement for
> > terminal dependent buffers (DFHCOMM area or SPA) or maintenance of state
> > (the system is stateless), and the whole thing is much more fail safe
> > because if parts of the network are down or missing, packets get
> > re-routed "automatically". (It was designed that way, as it was
> > developed from a military system called ARPANET that was designed to
> > enable the continuance of military command and control after parts of
> > the network were destroyed by nuclear attack.)
>
> The comparison is of totally different things. One is a application
> server (CICS) the other is a networking protocol (TCP/IP). SNA does
> keep track of the status of every terminal that it owns. TCP/IP does
> not keep track of every IP address within it's subnet. However, a
> distributed server using TCP/IP as it networking protocol does keep
> track of each client that is connected to it by IP address. A web
> server has a "DFHCOMM area" for each HTTP connection. A since getting a
> single web page from a single client can create up to 5 HTTP connections
> to a Web Server, this means that for an equal number of clients, a Web
> server is keeping track of 5 times the connections.

Here, you show that you do not understand subnets. TCP/IP keeps just
fine track of all the addresses on a single host. A subnet is only a
possible range -- using your implied criteria, does SNA keep track of
all possible LU's defined by an 8-byte name space?

And an HTTP connection can create as many connections as the receiving
client (and feeding server) will allow. Why only 5? Stateless
protocols operate in stateless ways.

You seem to be trying to confuse the benefits of fixed circuit
networking with virtual circuit networking. Or maybe just having an IE
moment.

> >> Sub-second response
> >> time is a major goal for many CICS systems. 3000 transactions a second
> >> may not be unusual for some of the larger systems.

Which decade are you in? You could add an order of magnitude to that.

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