changing AIX 3.1 JFS block sizes

[Kenneth Stailey]

I would like to try using filesystems with 8K blocks, but I can't seem
to find anything about this in info explorer.

The file /usr/include/jfs/fsparam.h contains a line that goes:

#define BSIZE           4096    /* size of file system block (bytes) */

suggesting that it is hard-coded, but the the "Tested Mettle" column
of _UNIX Review_ shows performance stats for 512 1K 2K & 8K bytes per
block file systems.

How do you make an 8K filesystem?  Can it be done without having the
source code to JFS?