Updating typed datasets
One of the reasons, why you should learn Rexx, is that it increases the productivity of the average Mainframe Programmer.Repetitive tasks which are tedious, and require manual labour can be automated using Rexx.As an example, suppose there are two Jobs(systems) 1 and 2. Generally in projects, they would express this fact as, .Suppose Job 2 has been scheduled to run at 12 o'clock.
How do you know, the location of your file(where is it) in this vast galaxy of Computer Memory space? The MVS Operating System keeps a diary/register, which contains name of each file, and its location in the computer memory. FILE, IDCAMS will print a description about the file to the log.
Remember, that Job 2 expects to pick up a file, which Job 1 will produce as Output.
If this file is not available by 12 o'clock, when the Job 2 is about to start, the Job 2 will fail(abnormally end) or abend.
Rexx was developed in the year 1979, by a programmer, Mike Cowlishaw, who is now a visiting professor at the University of Warwick.
The language Rexx is recommended for beginners, because it has a simple instruction set – just a couple of dozen instructions. Unlike COBOL, a Rexx program does not have a definite structure – like DIVISIONs, SECTIONs and Paragraphs.
Search for updating typed datasets:
The files are generally scattered everywhere haphazardly in Computer Memory.