I can see small one: nobody uses other geometry than 3390 (please,
let's forget 3380 and older stuff, I'm talking about life
datacenters, not musea).
I wish you were right, but you would be surprised how many customers we
run into still using 3380s (emulated, of course). Since z/OS and most
disk vendors still support them, it was probably easier at those sites
to leave data in 3380 format than go through the hassles of converting
them.
Device geometry conversion is often a hassle, which is why IBM is loath
to introduce a new geometry. Many datasets can be converted without
pain, but certain types of data do have geometry-dependancies which make
conversion an effort.
Some years ago IBM introduced a new rack-mounted disk 9345 which had a
new geometry. Bad decision. It flopped
Offering more tracks per cylinder without changing the 3390 track size
would be less painful but not painless. All allocations by cylinder
would have to be reviewed. CA size in VSAM is typically one cylinder.
Probably other implications.
--
Bruce A. Black
Senior Software Developer for FDR
Innovation Data Processing 973-890-7300
personal: [EMAIL PROTECTED]
sales info: [EMAIL PROTECTED]
tech support: [EMAIL PROTECTED]
web: www.innovationdp.fdr.com
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