DBSCHEMA automatically determines the number of data records that fit in a
block that makes the best use of disk space under the BLOCKMAX specified.

WHY NOT SIMPLY SPECIFY A BLOCKMAX=2560?

The data set entries are fetched from the disk into 4096 byte pages that
consist of the above blocks. When selecting BLOCKMAX you are trading off
disk space utilization versus fetching the block into multiple pages, and
the possibility of separating the bit map on the front of the block from
data at the end of the block.

 Mike

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