Why limit these devices to 15 tracks per cylinder? New hardware is capable
of emulating many different devices. Why not emulate a 150-track cylinders?
It would give a device 10 times the capacity.
That is one of the options, but such a disk would no longer have a
"3390" geometry (defined as track size plus tracks/cylinder). This
affects movement of datasets from the 3390 to the new device.
Unfortunately, cylinder size is also an issue in a lot of software. For
example, VSAM is sensitive to cylinder size; a CA is never more than one
cylinder (currently 15 tracks). All these issues are solvable, at a cost.
On the issue of variable disk sizes, the issue I see is disaster
recovery and data movement. First you need to be sure that your DR
vendor will provide volumes defined with the same size or larger. Even
larger sometimes poses some problems (how to do you go back to the
smaller disks at your home site?). If you need to migrate to new
hardware, will the new vendor support the same volume sizes?
--
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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