General coding notes

A SORTINnn data set should not be the same as the SORTOUT data set or any OUTFIL data set because this can cause lost or incorrect data or unpredictable results.
You can merge up to 100 data sets with Blockset merge or up to 16 data sets with Conventional merge. If Conventional merge is selected, check message ICE800I for the reason Blockset could not be used and correct the indicated condition, if possible.
- With Blockset merge, nn can be any integer from 00 (the initial zero is optional) to 99, in any order. Blockset merge treats ddnames of the form SORTINn and SORTIN0n as duplicates, and ignores any occurrences after: the first. For example, if you have
```
//SORTIN4 DD . . .
//SORTIN04 DD . . .
```
  the SORTIN04 DD will be ignored.
- With Conventional merge, nn can range from 01 to 16. The first number you use must be 01 and the remainder must follow in numeric order. Numbers cannot be skipped. Conventional merge cannot use ddnames of the form SORTIN0-SORTIN9, SORTIN00 or SORTIN17-SORTIN99.
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