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 <[email protected]> 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 > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
