On 09/30/2013 05:13 PM, Sampsa Laine wrote:
JCL is really easy once you begin to think "in JCL" instead than in DCL/whatever
script language. The weirdest thing it has is the COND expression, which works the
opposite it seems to have to work. Everything else is just syntax you can learn (or look
at in a manual).
I'm not quite there yet :) Need to read a bit more of the JCL books I have I fear.
But yes, it's not strictly speaking a scripting language, more like a definition of
how to run a payload (such as a COBOL compile+link), no?
In any case the syntax is WEIRD compared to DCL or bash, you have to admit..
DCL and Bourne shell are a combination of interactive and scripting
languages, while JCL is entirely a batch language. Its syntax reflects
its heritage and intended usage pattern.
As (primarily) UNIX people, we are trained to think in terms of
abstraction layers and common interfaces. The IBM mainframe world in
general, and JCL in particular, find no value at all in that.
Production shops today, on modern hardware, still sometimes think in
terms of allocating cylinders on disk drives for job output.
Once you get used to that, and realize that even though it may offend
your sensibilities at first, that it's really "ok", it all becomes much
easier.
JCL is fast to parse, efficient to execute, and hard to read and
write. The IBM mainframe world never bought into that bullshit idea of
"programmer time is more important than processor time", because, well,
it isn't. The programmer does whatever is fastest for the computer to
execute.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA