Re: ATTN: DD

On 3 Jun, 02:53, docdw...@panix.com () wrote:
> In article <1180822006.061423.92...@o5g2000hsb.googlegroups.com>,
>
> Alistair  <alist...@ld50macca.demon.co.uk> wrote: 
> 
> 
>
> I didn't remember it either until you just mentioned it now... I believe
> it had to do with addressing the same dataset by two different internal
> names, as in
>
> SELECT FILE01 ASSIGN TO FILE01.
> SELECT FILE02 ASSIGN TO FILE02.
>
> ... and the JCL (or however that platform related internal to external
> names) would be along the lines of:
>
> //FILE01  DD  DSN=SOME.DATASET.NAME,DISP=SHR
> //FILE02  DD  DSN=SOME.DATASET.NAME,DISP=SHR
>
> ... so that when, say, SOME.DATASET.NAME contained the following records:
>
> 0010
> 0020
> 0030
> 0040
> 0050
>
> ... then code similar to:
>
> PERFORM 4 TIMES
>     READ FILE01
>     END-READ
> END-PERFORM
> READ FILE02
> END-READ
> DISPLAY 'FILE01-REC = ', FILE01-REC
> DISPLAY 'FILE02-REC = ', FILE02-REC
>
> ... would (assuming a bunch of other stuff, such as FDs and the like) give
> output of
>
> FILE01-REC = 0040
> FILE02-REC = 0010
>
> ... where both records came out of the same dataset.
>
> Now, it seems, he wants to do it again... and this reinforces Yet Another
> Prejudice of mine, similar to the one against solutions which are prefaced
> by 'All ya gotta do is...' ... and that Prejudice is against someone who
> tells me 'We'll only need this once, just this once...'
>
> ... because - especially with computers, being the kind of devices they
> are - If Something Can Be Done Once Then That Something Can Be Done
> Forever.  An ugly, wretched, cobbled-together 'do it just this one time,
> no matter how' chunk of code becomes a part of the Production System...
> and then, as the System grows, this chunk of code is stretched beyond its
> design limits and starts to do Bad Things... and someone is sure to say
> 'Who wrote this crap, *anyone* can see it isn't fit to run...' ... when
> the circumstances of its current running are far, far different than those
> for which it was originally designed... which were to be '... once, just
> this once.'
>
> DD

I think that we have all been there with the run-once developments
that get further developed and become permanent solutions.