The fudge factor is architecturally taken right out of the RDC data returned from the hardware; this is a left over from the day's when FBA was really built on top of CKD.
We always fabricate this now as 777 512-byte blocks (per cylinder) for
simulated and emulated devices.
Steve Wilkins
IBM VM I/O
Rick Troth
<[EMAIL PROTECTED]>
Sent by: The IBM To
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System cc
<[EMAIL PROTECTED]
ARK.EDU> Subject
cylinder fudge factor for FBA (and
SAN and EDEV)
08/07/2008 11:53
AM
Please respond to
The IBM z/VM
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<[EMAIL PROTECTED]
ARK.EDU>
I notice on the ouptput from 'q dasd details' the "CYL =" value,
that it is present even if the disk is FBA (VFB-512 attached to CP
running second level, or EDEV attached to second level, or even first
level EDEV (on the "SAN connected" system). But fixed block do not
have cylinders that can be used by CP or CMS.
I guess the question is: what factor is used to calculate this number?
I might have expected dividing the size by 720K to fudge 3390 cylinders,
but it looks closer to maybe 360K. What's the story?
-- R; <><
