JCL is neither simple or powerful. It's a piece of poorly designed junk that 
should never have made GA. Even it's original implementers admit that it's 
rubbish. Try explaining the reverse logic of condition codes to a youngster and 
they will die laughing. 

Hey, how do I do a loop in this code?

Forget it kid, they didn't have rewind on punch card readers. 



> On 6 Nov 2013, at 10:06 pm, John Gilmore <jwgli...@gmail.com> wrote:
> 
> The notion that JCL is somehow hateful is widespread and not new.
> 
> In the 1970s a colleague kept telling me that [UNIVAC] Exec 8 was much
> superior to JCL.   He showed me what it required to compile and
> execute a FORTRAN program, which he thought compared very unfavorably
> with the JCL required to do the same thing.
> 
> I investigated and found that he was right; but there was a rub: Exec
> 8 was not good at doing much of anything else.
> 
> Gerhard Postpischil's point is the crucial one:  JCL is a well wrought
> compromise between simplicity and power.
> 
> Still, it has a bad reputation; and when the time came last year to
> teach it systematically to my teenage geniuses, I opted for a
> non-standard approach.  I asked each of them to write and test a
> lexical breakout routine for current z/OS MVS JCL in either C or PL/I,
> giving them a VDL definition of this JCL as a basis for doing so
> 
> They all succeeded.  (They are fiercely competitive, and it was all
> but foregone that if one did they all would.)  Then, having mastered
> the syntax and some of the semantics of JCL, they all learned to use
> it very rapidly.
> 
> I am not sure that this scheme would scale up, and there are other
> reasons to be wary of its generality.  Its success has, however, made
> me suspicious of the low-level, brutally empirical, step-by-step,
> from-simple-to-complex approaches to teaching and learning JCL that
> are usual in the industry.
> 
> There is, finally, something else in play here too.
> 
> If you want to sell someone a mass-market cell phone, you make it easy
> to use, even at the expense of functionality.
> 
> If, on  the other hand, a young statistician said to be that he didn't
> think Tauberians were user-friendly, i would want to help him to
> master whatever about them he found puzzling, but I would also make it
> clear to him that they were a part of the plumbing that he needed to
> master.
> 
> John Gilmore, Ashland, MA 01721 - USA
> 
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