[Tutor] aBSOLUTE BEGINNER

[Alan Gauld]

"bhaaluu" <bhaaluu at gmail.com> wrote 

> What does that mean... "mainframe technology"?

I'll take a guess at what it means.
A true mainframe is usually one of (or a clone of) IBM 
or ICLmainframe hardware running an OS like OS/390. It is 
primarily used for large volume data crunching and the 
applications use text only screens such as 3270 terminals 
running LU6.2 protocol. LU6.2 is somewhat like CGI 
on the web(*). A user is presented with a form which they 
fill in and submit as a job to the mainframe. The job 
executes and presents the results in the shape of 
another form. The coordination between transactions 
is managed by a system such as IBM's CICS.

(*)I've often thought a mainframe wouldmake the ultimate 
web server, but sadly I'll never find out as web apps are 
usually considered far too trivial to waste a mainframe on...

For the programmer or 'operator'(sys admin) the system 
involves a lot of small executables (programs) each 
wrapped up as a "job" in a script written in JCL 
(Job Control Language) which will define how much 
memory should be allocated, when the job should start, 
when it should terminate (regardless of whether it has 
finished), its schedulling priority, and so on.

Any scripting in the python sense tends to be done 
using REXX, but it still needs to be wrapped in JCL.
Everything is a job on a mainframe.

Mainframe people tend to regard Unix boxes in the 
same way Unix guys regard PCs - little more than 
grown up toys. Mainframes hardly ever fail, they run 
the world's top businesses. But they are expensive, 
they are used for data centric rathger than user-centric 
applications and so many people working on them 
find them a tad dull, or boring... I know I spent a very 
instructive year wotking on a mainframe project. 
I'm glad I did it, I learned a lot about writing super 
reliable programs , but I don't want to do another 
one - ever!

Now I may be assuming too much but I'm guerssing 
that's what the OP is referring to.

> Python is anything but boring! I doubt we can help you!

Well, Python is much more fun than either REXX or JCL so
learning Python may well bring some light relief.

Alan G.