On Sun, Apr 3, 2016 at 6:00 PM, Andrew Rowley <[email protected]> wrote:
> On 3/04/2016 22:43, David Crayford wrote: > >> Good question! Sort can be utilised for other purposes than sorting, it >> can be used as an I/O engine. DFSORT (or Syncsort) implements bespoke >> highly optinized I/O using low-level programming interfaces such as chained >> EXCPs which are significantly faster than using standard access methods >> like QSAM or BSAM, including overlapping BSAM I/O. DFSORT has exit routines >> (callbacks) which get called for each record. Basically it's supercharged >> I/O. One of our products does just that as do many others. IIRC, IBM >> FileManager uses sort for I/O. The trouble with using this technique with >> Java is the JNI/callback overhead. >> > > I'm aware of the efficient I/O, but I'm more interested in the use to put > data into a particular order. My own programs I never sort input data, > frequently sort small subsets of data during processing (likely always too > small quantities for something like DFSORT) and almost always sort for > presentation. Presentation is hopefully also too small quantities for > DFSORT. > > It is an interesting idea though to use it to read data via the exits > without actually giving it back to DFSORT to process. I'm not an application programmer. But I can just imagine the looks of astonishment and the "talk", if I were to write a COBOL program which does a SORT verb with INPUT PROCEDURE IS and OUTPUT PROCEDURE IS which only did a SORT FIELDS=COPY operation. Even more astonishment if I coded the INCLUDE or EXCLUDE to subset my data in addition to, or instead of, using COBOL code. I don't know if such coding would pass the majority of the "peer review" type processes. I'd love to try. Especially if I were smart enough to do so initially and keep the output listing. Then allow code review to force me to use normal COBOL methods. And then show the differences, assuming the SORT method actually is superior. Of course, I'd better know my management. I was at one shop (sysprog) where my boss (sysprog + manager) did that with a major application that would max the 3083 (long ago). Basically he proved it was due a flawed design. Unfortunately, that cost him him his job because the design was actually done by the head of the company (software development company). > > > -- > Andrew Rowley > Black Hill Software > +61 413 302 386 > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- How many surrealists does it take to screw in a lightbulb? One to hold the giraffe and one to fill the bathtub with brightly colored power tools. Maranatha! <>< John McKown ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
