-----------------------------------<snip>----------------------------------------
But this reminds me of the current struggle to extend DASD volume sizes
beyond 54GB, largely because IBM apparently at the introduction of the
3390 made a committment to support forever programmers with the
unconscionable habit of hard-coding device geometry parameters rather
than fetching them dynamically from system services. If no programmers
had hard-coded 15 tracks per cylinder, IBM could easily have supported
HH values up to 65535. It's all virtual, anyway, nowadays.
-----------------------------------<unsnip>-------------------------------------
One of the biggest problems in upgrading DASD was upgrading millions of
lines of JCL to account for altered geometry. Please remember that
updating JCL, or dynamic allocation parms, isn't "productive" in the
same way as implementing a new inventory management system, for example.
Most management types don't see any value in updating JCL and thus
aren't willing to commit manpower resources for this sort of thing.
Long ago, before the advent of SMS, IBM made a commitment to not change
device geometry after the 3390 was introduced. I, for one, salute IBM
for living up to that commitment.
Rick
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